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    • 专利摘要:
    Procedure of control of the collapse of structures of industrial establishments in case of fire. The object of the invention is a procedure that allows, by implementing a certain impairment at a specific point, or several, of the structure of the establishment in question, controlling the collapse thereof in case of fire, and for this the procedure includes (1) the characterization of the industrial establishment, which includes the determination of the actions or burdens that act on the structure of said establishment; (2) the design and calculation of the impairment to be practiced in the structure of said industrial establishment, especially considering the use of a screw as a thermomechanical fuse or, alternatively, the weakening by reducing the profile section of the structure; and (3) the implementation of the selected impairment. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2637466A1
    申请号:ES201631627
    申请日:2016-12-20
    公开日:2017-10-13
    发明作者:Francisco Javier HEREDIA CORTÉS；Carlos LÓPEZ TABOADA
    申请人:Universidad de Malaga；
    IPC主号:
    专利说明:

    CONTROL PROCEDURE FOR THE COLLECTION OF STRUCTURES OFINDUSTRIAL ESTABLISHMENTS IN CASE OF FIRE
    SECTOR OF THE TECHNIQUE
    The present invention falls within the construction sector, more specifically in the field of fire protection measures in establishments for industrial use.
    BACKGROUND OF THE INVENTION
    Currently, fire protection measures in establishments for industrial use are regulated, in Spain, by Royal Decree 2267/2004, of December 3, which approves the Fire Safety Regulation in Industrial Establishments.
    In the aforementioned Regulation, industrial buildings are classified according to their Configuration and their Location with respect to their surroundings, creating three types for the establishments located in the building:
    Type A configuration: Ships attached to others with shared structure.
    • Type S configuration: Ships attached to others without shared structure.
    • Type C configuration: Isolated building with a distance greater than 3 m from the rest of the buildings.
    Fire protection measures for a type A ship are more demanding than for one of type S, and in turn, type S measures are more demanding than those of type C. This causes that for a type A ship, and In particular, if it is intended to comply with the requirements of the regulations, whether old or new, the implementation of fire protection measures requires a large economic investment.
    As is well known, in most industrial estates, the most predominant type of construction is type A, since normally the execution of these buildings is done in groups, making a common structure for a set of ships.
    Well, the procedure object of the present invention is essentially aimed at ensuring that the structural behavior of a type A industrial building matches that corresponding to a type S industrial building, thereby reducing the legal needs and requirements in Regarding the fire protection measures to be implemented in these industrial establishments, as well as opening the door to place them in
    locations not allowed for type A buildings.
    . EXPLANATION OF THE INVENTION
    The object of the present invention is a collapse control procedure in case of fire of structures of industrial establishments comprising the following stages:
    one. Characterization of the industrial establishment whose collapse in case of fire is to be controlled.
    2. Design and calculation of the impairment to be practiced in the structure of said industrial establishment.
    1. Characterization stage
    In a preferred embodiment of the process object of the invention, the characterization step of the industrial establishment comprises obtaining information about its configuration and its location with respect to its surroundings, in particular information of its geometry, of the profiles of which the structure consists of the establishment (section and materials), and its geographical location, including the corresponding wind and climate zones. In an even more preferred embodiment, said step of characterization of the industrial establishment further comprises determining the level of intrinsic risk of the industrial establishment as a function of the weighted or corrected fire load density. In any case, such information can be obtained either experimentally, by observing and using the corresponding tools and methods, either from sources of documentation in which said information is available, or by combining documentary sources with experimental determinations. .
    In an even more preferred embodiment, the characterization stage of the industrial establishment comprises obtaining information on the actions or charges acting on the structure of said establishment. especially the actuators on vertical walls and roofs. In an even more preferred embodiment, said actions comprise:
    Permanent loads: own weight of all elements (structure, facades,
    covers, anchors, doors, etc.).
    • Snow overload: Action on the roof which, in a horizontal terrain, is determined by the altitude and the winter climate zone.
    • Wind action or load: Action on roofs and walls. Overload of use: Take into account the weight of people on the roof, for example when they climb on it to perform maintenance. Seismic action or load: Its value depends directly on the mass of the building.
    This information can be obtained either automatically, by using a calculation program to obtain actions in structures (for example, a program that automatically determines the values of the actions to be applied, defining the user, previously, the set of loads acting on the surface); well so no
    10 automated, by calculating the loads, with the help of the Technical Building Code (CTE), and its decomposition on the straps and pillars in the form of linear loads.
    In a preferred embodiment, the determination of the action of the wind on a vertical or covered wall comprises the determination of: • Dynamic pressure, depending on the geographical location of the establishment;
    • exposure coefficient, depending on the height of the building and the degree of roughness of the environment, whose value is always greater than the unit, varying strongly with the height; and pressure coefficient, which determines the direction of the wind (a positive value indicates that
    20 the wind exerts a pressure on the surface; a negative sign indicates suction), which, in turn and in a more preferred embodiment, decomposes into: o External pressure coefficient, depending on the shape of the roof or facing studied; Y
    or internal pressure coefficient, depending on the slenderness of the building and the
    25 location of the holes in it. This coefficient subtracts from the previous one, and considers the action of the wind inside the building, understanding that there are open holes in the envelope of the same.
    In an even more preferred embodiment, the wind action on a vertical or covered wall is determined by taking into account the three directions of the
    following wind: Wind + X: Corresponding to the direction parallel to the porches, it will determine the most important wind load on deck and on side pillars. In case of non-symmetrical structures, it is necessary to raise the wind in -X.
    35 • Wind + Y: Wind perpendicular to the front façade, which will be used to check the frontal gable portico and bracing.
    • Wind -Y: Same as the previous one, but on the rear facade.
    In said even more preferred embodiment in which the three possible wind directions are taken into consideration, the calculation of the wind (+ X) in vertical walls assuming closed gaps, load acting on the four faces of the building, comprises the determination of:
    Dynamic pressure,
    exposure coefficient, depending on the average height of the enclosure and the degree
    of roughness; Y
    • pressure coefficient, depending on the parameter in question, and being able to distinguish up to three different zones or regions in the case of side facades, in which case it is possible to adopt a single pressure coefficient per wall, calculated as the weighted average of the coefficients of each region, that is: opposite facade, opposite facade, and lateral facades.
    In said even more preferred embodiment, the calculation of the wind (+ X) in vertical walls assuming open gaps, assuming in which the internal pressure acts, it is necessary to determine, in addition to the dynamic pressure and the exposure coefficient, the pressure coefficient interior, depending on the slenderness of the ship, and the percentage of holes that are suction (or under pressure) when the wind takes the + x direction. Said internal pressure coefficient can be calculated, as in the case of the pressure coefficient in the case of wind (+ X) in vertical walls assuming closed gaps, separately for (1) facing facade, (2) opposite facade, and (3) side facades
    In said even more preferred embodiment, the calculation of the wind (+ X) in roofs with closed gaps is necessary to determine in addition to the dynamic pressure, the exposure coefficient, which in this case is dependent on the average height of the roof; as well as two pressure coefficients per skirt, one negative and one positive, which can be combined with each other to generate up to a total of 4 hypotheses of wind load on roofs, dividing the roofs into 5 regions: 3 in the windward skirt, and 2 in the leeward skirt. These pressure coefficients are dependent on the length of the ship, the heights of pillars, the length of light, and the percentage of slope, are calculated, according to the above, both in suction and pressure, and both windward as in leeward, resulting in four pressure coefficients that in turn determine four wind load values, depending on the scenario: windward / suction, leeward / suction, windward / pressure, and leeward / pressure.
    In said even more preferred embodiment, the calculation of the wind (+ X) in roofs with open gaps comprises the determination, in addition to the dynamic pressure, of the coefficient of
    exposure, and of the two pressure coefficients per skirt, one negative and the other positive according to the previous case, of two internal pressure coefficients, one per skirt (windward and leeward), so that four global pressure coefficients are obtained and , therefore, after multiplying them by the exposure coefficient and the dynamic pressure, four values of the 5 wind loads (suction / windward, pressure / windward, suction / leeward, and
    pressure / leeward). According to the above, up to a total of 8 wind modes can be taken into account for the + X direction (4 with open holes, and 4 with closed holes):
    • Mode 1: Gaps closed, pressure on both skirts.
    10 Mode 2: Gaps closed, pressure-suction.
    Mode 3: Closed gaps, suction on both skirts.
    Mode 4: Gaps closed, suction-pressure.
    Mode 5: Open gaps, pressure on both skirts.
    • Mode 6: Open holes, pressure-suction.
    15 Mode 7: Open holes, suction on both skirts. Mode 8: Open holes, suction-pressure.
    However, it is possible to reduce the number of wind modes to be considered for the + X direction, for which it is necessary to analyze the aforementioned wind modes, paying particular attention to those most unfavorable, and more particularly even to the so-called modes "3 ~ mode (closed gaps, suction on both skirts) and" 5 ~ mode (gaps
    open, pressure on both skirts).
    In said even more preferred embodiment in which the three possible wind directions are taken into consideration, the calculation of the wind (+ YI-Y) in vertical walls, wind 25 which will determine the size of the gable pillars and the elements of bracing of the ship, is determined in a similar way to the case of the wind + X but "turning the building around, including the determination of, in addition to the pressure values
    dynamic and exposure coefficient, which are the same as in the case of wind (+ X) in vertical walls, three external pressure coefficients, depending on the length of light 30 and height: One for the front facade, another for the back facade, and another for the facades parallel to the wind.
    In said even more preferred embodiment in which the three possible wind directions are taken into consideration, the calculation of the wind (+ YI-Y) on decks, wind that produces a suction effect on them and whose load is equal in both skirts, understand,
    35 in addition to the dynamic pressure, the exposure coefficient, which in this case is
    dependent on the average height of the roof, the determination of an external pressure coefficient. In accordance with the above, up to a total of 4 wind modes can be taken into account for the + Y / -y direction (2 with open holes, and 2 with closed holes): Mode 9: Wind + Y with closed holes.
    • Mode 10: Wind + Y with open gaps.Mode 11: Wind -and with closed holes.Mode 12: Wind -and with open holes.
    However, it is possible to reduce the number of wind modes to be considered for the + X direction, for which it is necessary to analyze the aforementioned wind modes, paying particular attention to those most unfavorable, and more particularly to the so-called "mode 1 O ~ (wind + Y with open holes).
    In said even more preferred embodiment, and for the particular case of non-symmetrical structures, the determination of the action of the wind on a vertical or covered wall is also made taking into account the wind in -X.
    In a preferred embodiment, the calculation of the load or seismic action is performed by the simplified method of equivalent static forces. In an even more preferred embodiment, said calculation comprises the determination of:
    The acceleration of calculation,
    • the periods and modes of vibration,the response coefficient, which depends on the level of ductility;
    • the masses involved, and
    • equivalent static forces.
    In an even more preferred embodiment, the calculation acceleration determination comprises the determination of:
    • The basic acceleration, the dimensionless risk coefficient, which measures the probability that the building exceeds its useful life of calculation;
    • the land coefficient, and
    • the amplification coefficient of the terrain.
    • The characteristic periods of the response spectrum,
    In an even more preferred embodiment, the determination of vibration periods and modes comprises the determination of:

    • the fundamental period of the building, which depends on the type of structure and the number of floors of the building, and on which the number of vibration modes depends; Y
    The value of the response spectrum.
    In a preferred embodiment, the masses to be considered in the calculation are the proper weight, permanent loads, snow overload, and usage overload.
    2. Design and calculation stage
    The stage of design and calculation of the weakening to be practiced in the structure includes both the calculation of the thermal load and the analysis of the behavior of both the unconstrained structure and the theoretically weakened structure, depending on which the weakening is finally decided. implement in a practical way, what constitutes the last stage of the process object of the invention.
    A thermal load or thermal solicitation is an indirect force, solicitation or action that appears in a resistant structure as a result of an impeded or conditioned dilation. That is, when heat is applied to a resistant element, it undergoes temperature changes and deforms as a result of them, that deformation alters the distribution of tensions in the body. The result of the new stress distribution is loads and stresses not exerted directly by any external agent but which have an effect that can affect mechanical stability.
    As indicated in section 3.4 of the Basic Structural Safety Document Building Actions (08 SE-AE) of the CTE, buildings and their elements are subject to deformations and geometric changes due to variations in the ambient outdoor temperature. The magnitude of them depends on the climatic conditions of the place, the orientation and the exposure of the building, the characteristics of the building materials and the finishes or coatings, and the heating and indoor ventilation regime, as well as the thermal insulation.
    These variations of the temperature in the building lead to deformations of all the constructive elements, in particular, the structural ones, which, in cases where they are impeded, produce tensions in the affected elements.
    On the other hand, the arrangement of expansion joints can help reduce the effects of temperature variations. In usual buildings with structural elements of concrete or steel, thermal actions may not be considered when expansion joints are arranged so that there are no continuous elements of more than 40 m in length.
    In a preferred embodiment, the calculation of the thermal load in case of fire comprises the determination, for a given time, of the air temperature, depending on the location of the structure, and the temperature of the construction material of the structure. In
    an even more preferred embodiment, the determination of the air temperature comprises the determination of a maximum temperature, a minimum temperature, and a reference temperature.
    In a preferred embodiment, the analysis of the structure behavior in case of fire is carried out in accordance with Schedule 8 rActions for thermal analysis) of the EAE-11 and therefore includes:
    • The selection of fire scenarios,
    The determination of the corresponding calculation fire action; the
    calculation fire action, or abbreviated "calculation fire", by the curve
    of increase of temperature of the gases of the fire enclosure infunction of
    time, which is taken to characterize the action of the fire. When selecting fire
    of calculation you can opt for an appropriate mathematical model of a fire
    real good for the curvenormalized time-temperature represented by the program
    thermal test furnaces.
    • Hecalculationfromtheevolutionfromthetemperatureinheinsidefromtheelements
    structural as a result of its exposure to the fire of calculation adopted. Whether
    choose a real fire model, the calculation should cover the entire duration of the fire,
    with the cooling phase included. If you opt for normalized fire, in which no
    There is cooling phase, the time of exposure to the prescriptive fire must be set
    following the specifications of the regulations in force.
    • The calculation of the mechanical behavior of the structure exposed to fire along
    of a specific time interval.
    Thus, in order to identify the accidental calculation situation, the appropriate calculation fire scenarios and the associated calculation fires are determined, based on a fire risk assessment. For each calculation fire scenario a calculation fire is considered in a fire sector. The calculation fire is applied only to one sector of fire in the building at a time, except when otherwise specified in the scenario of said fire. For those structures for which national authorities specify fire resistance requirements, it may be assumed that the appropriate calculation fire is the normalized fire, except when otherwise specified.
    On the other hand, the following procedures are used depending on the calculation fire adopted: With a normalized time-temperature curve, the thermal analysis of the elements
    Structural is applied for a specified period of time, regardless of the cooling phase. This curve is defined by
    = 20 + 345 log (Bt + 1) ['C] EC.1
    Where: 89 Gas temperature in the fire sector [oC)
    5 T elapsed time [min)
    The convection heat transfer coefficient is: ac = 25 W / m2 K.
    • With a real or natural fire model, the thermal analysis of the elements
    10 structural is made for the entire duration of the fire, including the cooling phase. Real or natural fire models are models that, with greater or lesser complexity, incorporate various physical parameters present in the development of a real fire. Among the natural fire models are simplified and advanced fire models.
    15 Simplified fire models are based on specific physical parameters with a limited field of application. When simplified fire models are used, as convection heat transfer coefficient, ac = 35 W / m2 K will be adopted, and gas temperatures will be adopted based on physical parameters, considering at least the fire load density and conditions of
    20 ventilation When it is unlikely that sudden generalized flash-over inflammation is reached, the thermal actions corresponding to a localized fire should be taken into account, in which an uneven distribution of temperature is assumed as a function of time, as opposed to fires of sector. Advanced fire models should take into account the properties of the
    25 gas and the exchange of mass and energy. In particular, the following properties of gas, mass exchange, and energy exchange should be taken into account.
    As regards the thermal analysis of an element, the position 30 of the fire with respect to said element must be taken into account. For external elements, exposure to fire through the openings of the facades and roofs is considered. For the walls
    delimiters of a fire sector is considered, where appropriate, exposure to a fire inside that sector and, alternatively, to an external fire in other fire sectors.
    Also, to obtain the evolution of the temperature in the structure, it is necessary to distinguish between elements without protection and elements with protection, as the EAE-11 considers. The latter are usually carried out, in the case of steel, through the application of intumescent paints, mortars based on rock wool / plaster or the installation of plaques.
    5 calcium fibrosilicate, with a thickness that is provided by the manufacturer in its tests infunction of the massiveness of the element to be protected.
    With regard to mechanical analysis, the duration considered for said analysis must be the same as for thermal analysis. Fire resistance verification can be done in one of the following ways:
    10 The calculation value of the fire resistance is greater than the required fire resistance time.
    • The calculation value of the resistance of the element in a fire situation at a time t, is greater than the value of calculation of the relevant effects of the actions in a fire situation at time t.
    15 • The material temperature calculation value is lower than the material critical temperature calculation value.
    When a structure is subject to fire, there is a considerable increase in the temperature in it. This increase in temperature causes the properties to vary
    20 of the structural elements, such as the elastic limit and the modulus of elasticity, so it is necessary to adopt the following corrective coefficients of the mechanical characteristics of the structural steel, depending on the temperature reached by it (9a):
    Quotient between the effective elastic limit for temperature (ea) and the elastic limit at 20 oC.
    EC.2
    Quotient between the modulus of elasticity in the linear phase of the diagram
    stress-strain, for temperature (ea) and modulus of elasticity
    at 20 ° C.
    EC.3
    The application of these coefficients is valid if the simplified calculation models of the temperatures of the steel included in the Instruction, or other procedures admitted by the same, are applied, but in this second case it must be verified that the speed of
    5 temperature increase remains within the limits 2 Sdea / dt s 50 ° C / minute.On the other hand, the following parameter:
    Quotient between the limit of proportionality for the temperature (ea) and the elastic limit at 20 oC. EC.4
    Together with the above, it is involved in the formulation of a uniaxial strain (E) strain (E) diagram (figure 1) that can be adopted if advanced calculation methods are used.
    In a preferred embodiment, the behavior of the structure in case of fire is analyzed by calculation of flat structures, more preferably by analysis of flat reticular structures, more preferably even by the stiffness method,
    15 considering that (1) the load is due to a linear variation of the temperature at the edge of the bar, and therefore is defined by its average value and its gradient along the edge, and (2) that the temperatures they are uniform along the entire length of the bar, although it is possible to analyze said bar as if it were divided into several "virtual segments" so that the temperature will vary along the profile that forms the lintel.
    In a preferred embodiment of the invention, the stage of design and calculation of the weakening to be practiced in the structure of said industrial establishment is carried out taking into consideration the method of weakening by decreasing the profile section.
    As indicated in the RSCIEI Application Guide, the protection systems of metal structures are essentially based on the coating of the profiles with 25 insulating materials.
    Among the most used systems are the following: Fire-resistant plates or panels, which are composed of calcium silicates or other materials. They are installed covering the entire perimeter of the metal profile and its thickness depends on the form factor, the coefficient of thermal conductivity of the
    30 lining and the arrangement in the profile work, being able to reach fire resistance up to R 240. 12
    Intumescent paints, which are products that in contact with heat undergo a transformation due to chemical reactions, which prevents the transmission of heat to the
    element to protect. The most common is that fire resistance is reachedup to R 60 (currently there are paintings that reach an R90 if the mass does not5 is very unfavorable). Keep in mind that this product is in fullevolution.
    Mortars, which are protection systems by coating the profile with mortar projection. Like the plates, the thickness of protection will depend on the form factor, the coefficient of thermal conductivity of the coating and the arrangement in the work of the profile, being able to reach fire resistance up to R
    240.
    The method of weakening by decreasing the profile section is to modify (weaken) the structure at a certain point, in the least requested areas in
    15 as far as supported stresses are concerned, modifying its dimensions, geometry, mechanical values, etc., in order to make it precisely that point where the structure collapses, so that said collapse is "controlled ~."
    To do this, first you have to check the structure, with a certain weakened area, in a conventional situation, that is, without fire. Once it has been proven that the
    20 structure is within the appropriate resistance limits, we proceed to study the evolution of the structure's behavior in case of fire, depending on the temperature that is reached at each moment, considering the alterations of the characteristics of the material by effect of the action of fire. As you can imagine, there are many ways to weaken a profile based on doing
    25 cuts in it so that its section is reduced. Depending on where we make the cut, it will influence to a greater or lesser extent its mechanical characteristics, and fundamentally in its moment of inertia. In fact, what must be done is to develop an iterative process in which the uncertainty begins and the results are refined step by step, until the most optimal solution is reached. In good
    30 The number of iterations will depend on the previous experience of the engineer. In another preferred embodiment of the invention, the stage of design and calculation of the impairment to be practiced in the structure of said industrial establishment is carried out taking into consideration the use of screw as a thermomechanical fuse.
    As in the case of the profile section reduction method, this method is that in case of fire, the structure collapses through a specific point, through a less requested area in terms of supported stresses. . so that
    displacements of the lintel-profile junction, that is, the horizontal displacements of the junction point between the roof beam and the pillar or profile, do not compromise the sectorization with the adjacent ships or, in other words, do not cause structural damage to the sectorization elements thereof.
    The method consists of placing a short piece (screw or similar) of certain characteristics at that point, so that in case of fire, it fails before the rest of the structure, so that it serves as a thermomechanical fuse. This method is more advisable in newly built ships, while the method of decreasing the profile section is more advisable, for its simplicity, in existing ships.
    To generate said thermomechanical fuse, the first thing to be clear is that, if you want to join two pieces for example of steel, the joint element must not be of the same material, but you need to find a material that has a module of elasticity that behaves differently with the increase in temperature. This condition is indispensable so that we can achieve the failure of the connecting element before that of the structure itself.
    On the other hand, it is also important to define the way in which these two pieces will be joined, for which there are several aspects to be determined:
    • Location of the weakened union. Embodiment of said union (by recessed connection, by ball joint).
    • Dimensions of the short piece (screw or similar), for which it is necessary to take into account the existing conditions both in the presence and in the absence of fire. Manufacturing material the short piece (screw or similar).
    In this document, which illustrates the behavior of steel elements with increasing temperature, it can be seen that the modulus of elasticity falls from a certain temperature value, but instead the elastic limit does not vary until that a much higher temperature of the element is achieved. This leads us to the conclusion that deformations occur in the structure before it can produce the same, and that is why we must look for a material that, on the one hand, supports the tensions to which it will be subjected, and on the other hand, that the elastic limit falls to a much lower temperature than steel, so that the joint element can make a true thermomechanical fuse.
    In addition to this, it should be borne in mind that the use of another type of metal other than steel can cause galvanic corrosion problems, unless a metal is chosen that has such a potential as steel, that the galvanic current is virtually negligible. Notwithstanding the foregoing, there are methods of avoiding such galvanic corrosion,

    how can it be:
    Electrically isolate the two metals by placing an intermediate insulator.Protect the most noble metal with plastic coatings and epoxy resins.Electroplating or electroplating techniques.Cathodic protection.
    Although these solutions are complicated in some cases to execute and in others they do not guarantee 100% protection over time, which would require maintenance operations.
    Based on the above, ideally the choice of material for the connecting element that does not
    It is metallic (which must also be isotropic) should take into consideration: A priori, the aforementioned limitations regarding galvanic compatibility and mechanical behavior as a function of temperature, suggest the use of a polymer. The maximum temperature of SelVicio, seeing the temperature of the steel in the 60th minute of fire, should be around 200 ° C. Of course, this temperature is only one orientation, because once the material has been chosen, which will have a specific specific heat, it would be necessary to calculate its temperature in the 60th minute, as was done with the steel. The connecting element is going to be protected with the same thickness as the rest of the structure, that is, with 3cm. If possible, we should look for a material with a specific heat similar to that of steel, so that the two materials increase their temperature over time at a similar rate. In addition, the material we use must be compatible with the projected rock wool, although this condition is easy to achieve, since this product is one of the most inert that exists, it is composed of cement mixed with volcanic rock wool.
    In a preferred embodiment, the material has an elastic limit between 40 and 230 MPa,In a preferred embodiment, the material has a maximum sealing temperature between
    180 and 290 oC, more preferably between 200 and 270 oC. In a preferred embodiment, the material has a specific heat between 940 and 1300 J / kg K. In a preferred embodiment, the material is a polymer composed of fiberglass and
    mineral, more preferably PPS 53% GLASS FIBER AND MINERAL, marketed under different brands (Amorvon; Bearee; Celstran; Ceramer; Compodic; Encare; Fiberfil; Fardan; Fortran; Larton; Lusep; Murdotec; Novapps; Petcoal; Primef; Pyrofil; Ryton ; Ryulex-C;
    Scanrex; Schulatec; Starglas; Suntra; Supec; Susteel; Tecatron; Techtron; Tedur;TismoPoticon; Torelina; Tripps)
    BRIEF DESCRIPTION OF THE FIGURES
    Figure 1. Diagram tension (o) -deformation (E) uniaxial for steel.Figure 2. Pressure coefficients for wind (+ X) in vertical walls assuminggaps closed.Figure 3. Pressure coefficients for wind (+ X) on roofs assuming closed holes.Figure 4. Wind load values for wind (+ X), closed gaps, pressure in bothskirt.Figure 5. Values of wind loads for wind (+ X), closed gaps, pressure -suction.Figure 6. Wind load values for wind (+ X), closed gaps, suction in bothskirt.Figure 7. Wind load values for wind (+ X), closed holes, suction-pressure.Figure 8. Wind load values for wind (+ X), open gaps, pressure on bothskirt.Figure 9. Wind load values for wind (+ X), open holes, pressure · suction.Figure 10. Wind load values for wind (+ X), open holes, suction in bothskirt.Figure 11. Wind load values for wind (+ X), open holes, suction-pressure.Figure 12. Wind load values for wind (+ Y), closed gaps.Figure 13. Wind load values for wind (+ Y), open gaps.Figure 14. Wind load values for wind (-Y), gaps closed.Figure 15. Wind load values for wind (-Y), open gaps.Figure 16. Illustrative scheme of ship attached to other ships on both sides and withshared structureFigure 17. Illustrative scheme of a ship attached to another ship only on one side,being in contact with the outside on the free side.Figure 18. Option 1 of profile weakening.Figure 19. Profile weakening option 2.Figure 20. Option 3 of profile weakening.Figure 21. Case 1-0-0-3-0, wind loads mode 5 (but without side wind) and thermal loadunder conventional conditions.Figure 22. Case 1-0-0-3-0, linear loads on the porch.Figure 23. Recessed connection scheme.
    Figure 24. Distribution of stresses in a section under f1eclor and low stressshear corresponding to the recessed connection schematized in figure 23.Figure 25. Axil stress distribution corresponding to the recessed jointschematized in figure 23.Figure 26. Scheme of the failure of the recessed connection schematized in Figure 23.Figure 27. Tension at the lousy points of bars 3 (A) and 4 (B) in the case of joiningrecessed with fire.Fig. 28. Efforts in the local system of the dummy bar element 4 in the case of joiningrecessed with fire.Figure 29. Efforts in the local system of the dummy bar element 4 in the case of joiningrecessed without fire.Figure 30. Articulated joint scheme.Figure 31 Tension at the lousy points of bars 3 (A) and 4 (B) in the case of joiningarticulated with fire.Fig. 32. Efforts in the local system of the dummy bar element 4 in the case of joiningarticulated with fire.Figure 33. Tension at the lousy points of bars 3 (A) and 4 (B) in the case of joiningarticulated without fire.Fig. 34. Efforts in the local system of the dummy bar element 4 in the case of joiningarticulated with fire.Figure 35. Diagram of elongation in the longitudinal direction of the screw axis.Figure 36. Diagram of elongation in the direction perpendicular to the axis of the screw.Figure 37. Diagram of screw diameter 20 mm and hole diameter 21.5 mm.
    PREFERRED EMBODIMENT OF THE INVENTION
    Although the procedure object of the present invention must be particularized for each specific case, the following is illustrated by its application to an industrial building whose typology is quite common in the industrial areas of the city of Malaga, of its municipality, and quite possibly from much of the national territory. It should also be noted that the present example of realization of the invention aims to control the collapse in case of fire of structures of industrial establishments in accordance with the legislation prevailing in Spain, especially with Royal Decree 226712004, of December 3, whereby the Fire Safety Regulation in Industrial Establishments is approved, Regulation that includes the type of ships type A, BYC in relation to the establishments located in the building, as well as the legally required protection measures for each of these types A, BY C.
    It is also noteworthy that, due to the area of the chosen industrial establishment, the option of qualifying it as type A or type B is particularly relevant. For example, it is not the same to have to occupy a space of about 30 m2 in a warehouse of 350 m2 than in one of
    5 1000 m2. The same goes for the investment, it is assumed that the initial investment for a larger ship must also be higher than for a smaller ship, so the percentage of the total budget allocated to fire protection measures will be lower.
    1. Characterization of the industrial establishment whose collapse in case of fire is to be controlled 1.1. Geographic characteristics. climatic and geometric
    According to the above, having been determined that the predominant ship in the polygons
    15 analyzed industrial has a porch light between 10 and 14 m and a height between 5 and 8 m, depending on the polygon in question, it has been established as a type industrial establishment for the present example of realization a ship with geographical features and climatic, as well as geometric, referenced in tables 1 and 2, respectively.
    Geographic location Malaga
    Wind Zone-Annex D, OS SE-AE, fig. D.1 TO
    Situation-table 3.4, section 3.3.3 OS SE-AE Environment IV - Urban area in general, industrial or forestry
    Climatic Zone-Annex E, OS SE-AE, fig. E.2 6
    Altitude 8-9 m above sea level.
    Table 1
    light 12 m
    Length (length) 30 m
    Height pillars to head of supports 7m
    No. of porches 7 separate porches every 5 m
    Cover Slope Approx. 15% -9,460
    Ridge height 8 m
    Length and .. lintel 6.08 m
    Table 2 1.2. Building actions
    Once the geometry of the ship is known, it is necessary to determine the actions that act on the structure. 1.2.1. Permanent Loads
    The permanent loads to consider will be: Galvanized steel sheet 1 mm thick: 0.09 kN / m2 0 :: 9 kg / m2 Sheet anchors: we can consider 0.03 kN / m2 or :: 3 kg / m2 • Weight of the doors: we will consider 0.15 kN / m2 or :: 15 kg / m2 • Own weight of the structure: we approximate it to 0.33 kN / m2.
    Thus, the permanent loads will be 0.6 kNJm2 • 1.2.2. Snow overload
    Snow overload is calculated from the data shown in Schedule E of CTEDB-SE. To specify per m2 of cover it is necessary to take into account its inclination.
    Sn = 0.2 kN 1m2. cos 9.46º = 0.19 7 kN 1m2
    EC.S
    Due to the shape of the roof, snow accumulation is not necessary.
    1.2.3. Wind Action
    In principle, the structure for three wind directions will be calculated: Wind + X (being the symmetric structure, it is not considered necessary to raise the wind in -X), wind + Y and wind
    Y.
    Wind (+ X) in vertical walls: assuming closed holes.
    This load acts on the four faces of the building. The steps to follow to calculate the vertical load will be:

    Dynamic pressure: As indicated in table 3.4 of section 3.3.3. from DS SE-AE, ANNEX D, ZONE A, we obtain a value of 0.42 kN / m2. It can also be obtained by looking at the
    sheet AE.01, for zone A we have 0.42 kN / m2 (logically, this value will be the same for all wind loads of the building).
    Exposure coefficient: again on sheet AE.01, we look at the exposure coefficient for the average height of the enclosure (DB-SE-AE 3.3.3 Pto.1). The height of the enclosure under study is 7.00 meters, as we can see in the plans. For a degree of roughness IV (industrial environment), we obtain an exposure coefficient equal to 1,336.
    Pressure coefficient: it will take a different value depending on the face in question, and in the case of the side facades, the CTE distinguishes between three different zones. For simplicity, we will use a single pressure coefficient per parameter, calculated as the weighted average of the coefficients of each region. We can extract the average values of the external pressure coefficient of the sheet
    AE.02:
    o Facade facing: for a height h = 8.00 meters, and 12 meters of light from the ship, it is obtained in the table of "Side facades ~ of sheet AE.02, cp = 0.756
    o Opposite facade: taking the same table as in the previous case, cp = -0.411.
    o Side facades: in this case, the height / light ratio is equal to 8.00 / 12 = 0.67, and the roof slope 15%. Referring to the table "Front 1 Rear ~ of sheet AE.02, you get cp = -0.854.
    Operating with the values obtained, the values referred to in table 3 and represented in figure 2 are obtained.
    Wind + X on facade with closed gaps
    Pressure Coefficient Coefficient Wind load
    dynamic kN / ml exposure pressure kN / m2 Effect
    0.42 1.336 0.756 0.424 Pressure
    0.42 1.336 -0.411 -0.231 Suction
    0.42 1.336 -0.854 -0.479 Suction
    Confronted
    Oppose
    Pa ralela
    Table 3
    Wind (+ Xl in vertical walls: assuming open holes
    Assuming the openings of the front façade are open, so that the internal pressure acts, the value of the internal pressure coefficient can be obtained in sheet AE.01 of the Prosecutor's Office. The slenderness of our building is 8/12 = 0.67 <1, and 100% of the gaps are in suction when the wind takes the direction + K Thus, entering the corresponding table, the
    5 internal pressure coefficient is -0.5 (internal suction).
    The pressure coefficients will be:Facade facing: in this case, there are: 0.756 - (- 0.5). cp = 1, 256Opposite facade: in this case the following are subtracted: -0.5 - (- 0.411). cp = -0.089.Lateral facades: in this case the following are subtracted: -0.854 + 0.5. cp = -0.354.
    Operating with the new coefficients, the values referred to in table 4 are obtained.
    Wind + X on facade with open holes
    Dynamic pressure kN / m2 Exposure CoefficientPressure coefficientWind load kN / m2Effect
    Enf rented 0.421,3361,2560.705Pressure
    Opposite 0.421,336-0.089-0.049Suction
    Parallel 0.421,336-0.354-0. 199Suction
    Table 4
    Wind (+> 0 on decks with closed holes
    For the calculation of the wind load on roofs we will take the same value of the dynamic pressure: 0.42 kN / m2. Regarding the exposure coefficient referred to the average height of the roof: 7.50 meters; interpolating between the values in table 3.4 of the DB-SE-AE, ce = 1, 588 is obtained.
    The DB-SE-AE defines in each skirt two pressure coefficients, one negative and one positive, which can be combined with each other to generate up to a total of 4 hypotheses of wind load on roofs.
    25 For the calculation of the pressure coefficient, the CTE divides the roofs into 5 regions: 3 in the windward skirt, and 2 in the leeward skirt. Calculating the loads for each of the regions can be unnecessarily complicated, so we will use the tables on sheets AE.03a and AE.03b, which contain average values of the pressure coefficient for a 50-meter long ship, for pillar heights of 5 and 10 meters.
    30 Interpolating for a height h = 7.5m from the coefficients calculated for h = 5m and h = 10m, the pressure coefficients referred to in Table 5 and represented in Figure 3 are obtained, and from these pressure coefficients are obtained the wind loads referred to in table 6.
    H = 7.5m
    Windward Leeward
    Suction -0.671-0.682
    Pressure 0.0710.235
    Table 5
    Wind (+ X) on roofs kN / m '
    Barl ove nto Leeward
    Suction -0.448-0.455
    Pressure 0.0470.157
    Table 6
    Wind (+) () on decks with open holes
    15 As with vertical loads, the internal pressure coefficients must be taken into account to consider the case of open holes. Thus, considering the internal pressure coefficient equal to -0.5, the new global pressure coefficients are referred to in table 7, and multiplying them by the exposure coefficient and dynamic pressure, the values of the loads of wind referred to in table 8.
    H = 7.5m
    Windward Leeward
    Suction -0.171-0.182
    Pressure 0.5710.735
    Table 7 Table 8
    Wind (+ X) on roofs kN / m '
    Barlove nto Leeward
    Suction -0.114-0.121
    Pressure 0.3810.490
    Based on the calculations made in the previous cases, there are a total of 8 modes of
    5 wind for the + X direction (4 with open holes, and 4 with closed holes):Gaps closed. Pressure on both skirts (mode 1, figure 4).Gaps closed. Pressure -Suction (mode 2, figure 5).Gaps closed. Suction on both skirts (mode 3, figure 6).Gaps closed. Suction -Pressure (mode 4, figure 7).
    10 open holes. Pressure on both skirts (mode 5, figure 8). Open holes. Pressure -Suction (mode 6, figure 9). Open holes. Suction on both skirts (mode 7, figure 10). Open holes. Suction -Pressure (mode 8, figure 11).
    15 This number of wind modes would generate a large number of very similar hypotheses and of little use. Ideally, stay with two wind modes only, since of the eight possible cases, most will be negligible. To choose the wind modes to be used in the calculation, we consider which are the most unfavorable:
    Highest load on the lintel: MODE 3.
    20 Greater arrow in the lintel: MODE 5, because the actions on the deck go in the same direction as the gravitational charges, and their effect is added. Highest load on a pillar: MODE 5, also 6-7-8, but mode 5 is also the one with the greatest arrow on the lintel. Greater horizontal displacement: MODE 2, because the sum of the actions has the
    25 largest possible horizontal component.
    Thus, in principle the most unfavorable wind modes are 2, 3 and 5. However, the importance of the criterion of horizontal displacement in industrial buildings is moderate (this would not happen, for example, in buildings with several floors), since elE only demands a
    30 limit of that displacement for almost permanent combinations. So in principle, mode 2 will be neglected, and mode 3 and mode 5 will be studied.
    Wind (+ Y / -Y) in vertical walls
    The dynamic pressure remains 0.42 kN / m2, and the exposure coefficient is 1,336. To obtain the external pressure coefficient on the front and rear facades,
    5 we will enter the table of facades perpendicular to the wind TABLE AE02 with a light of 30 meters and a height of 8.00 meters, which interpolating, gives coefficients of 0.705 on the front and -0.327 on the back.
    The H / L ratio is now 8.00 / 30 = 0.267. Entering with this value in the Facades table for / e / as a / wind we obtain, by interpolation, a value of the external pressure coefficient 10 of -0.674 Thus, the wind loads + Y / -And in the facades they will take the referred values in table 9.
    Wind + Y / -Y in facade with closed gaps
    Confronted
    Opposite
    Parallel
    Dynamic pressure kN / m1
    0.42
    0.42
    0.42
    Exposure Coefficient
    1,336
    1,336
    1,336
    Pressure coefficient
    0.705
    -0.327
    -0.674
    Wind load kN / m1
    0.396
    -0.183
    -0.378
    Effect
    Pressure
    Suction
    Suction
    Table 9
    Now, the internal pressure coefficient will vary depending on whether the wind blows in + Y or
    in -Y, since the ratio of suction holes f to pressure holes changes: Wind + Y: The percentage of suction holes is O, and the internal pressure coefficient 0.705.
    20 Wind Y: The percentage of suction holes is 100, and the internal pressure coefficient -0.327.
    Operating with the previous values, similar to what was done with the wind + X, the values referred to in table 10 are obtained.
    Wind + Y on facade s with open holes
    Cpe CpiCpq (kN / m ')Effect
    Confronted 0.7050.7050.0000.000---
    Opposite -0.3270.705-1,032-0.579Suction
    Parallel -0.6740.705-1,379-0.774Suction
    Wind -Yen facades with open holes
    Cpe CpiCpq (kN / m ')Effect
    Confronted 0.705-0.3271,0320.579Pressure
    Opposite -0.327-0.3270.0000.000-
    Parallel -0.674-0.327-0.347-0.195Suction
    Table 10
    Wind (+ Y / -Y) in Decks
    The frontal wind produces on the roofs a suction effect that is included in the table
    0.6 b) from 08-SE-AE. The average values of the external pressure coefficient for this case, which in industrial buildings will always be around -0.6, are tabulated in sheet AE.04 of the record.
    10 If we observe in the aforementioned sheet the values that we have for our case range between -0.576 of the ship with 5 m height and 20% slope to 0.618 of the ship with 10 meters high and 15% dependent. In a simplified way, we will take cp = -0.6.
    Thus, the wind load + Y / -Yen the roofs (same in both skirts) takes a value of:
    q = 0.42 kN / m "1,336 '(-0.6) = -0.337 kN / m' (suction) EC.6
    15 Now, as in the previous case, of the wind Y in facades, in the case of open gaps the values of the loads will change in the + Y / -Y directions, depending on the value of the internal pressure coefficient, the values referred to in table 11
    Wind + Y / -Yen facades with open holes
    Cpe CpiCpq (kN / m ')Effect
    + y -0.6000.705-1,305-0.732Suction
    -Y -0.600-0.327-0.273-0.153Suction
    Table 11 In the same way as in the case of wind + X, it is possible to distinguish a total of 4 modes of

    wind for the + Y direction (4 with open holes, and 4 with closed holes):
    + and with closed gaps (mode 9, figure 12).
    + Y with open gaps (mode 10, figure 13).-And with closed gaps (mode 11, figure 14).
    5 - With open gaps (mode 12, figure 15).
    and now we have to consider what ways to take:
    Greater load on the lintel: MODE 10 (it is logical that the greatest suction on the roof is given when the wind enters through the holes).
    10 Increased load on the posterior gable portico: MODE 10
    Increased load on the frontal gable portico: MODE 9
    Higher load on main pillars: MODE 10.
    It is clear that the most unfavorable mode is No. 10. 1.2.4. Use Overload
    The overload of use on roofs of this type is given by table 3.1 of D8-SE-AE. The overload of use takes a value of 0.4 kN / m2 • But there is a note under this table that indicates that "this overload of use is not considered concomitant with the rest of the variable actions".
    Thus, it makes no sense to consider this load, if we are already taking into account a snow overload of practically the same value, which is concomitant with the rest of
    variable actions. 1.2.5. Seismic action
    The basic acceleration of Malaga is 0.11 g And therefore, the NCSE-02 standard is applicable as it is greater than 0.04g and is a building of normal importance, that is, its
    30 earthquake collapse may cause casualties or damage to third parties. Therefore, it is mandatory to consider the seismic load in the calculation of the structure, although as we shall see, in industrial buildings it is not usually an important load. We will apply the simplified method of equivalent static forces to determine the seismic action applicable to the ship.
    Acceleration Calculation To calculate the acceleration calculation we need to know:
    Basic acceleration (ab), which for Málaga is 0.11 g.
    Dimensional risk coefficient (p), which measures the probability that the building
    5 exceed its calculation life. For constructions of normal importance it is equal to
    1.0.
    Ground coefficient (C), it will be considered a firm clay, which according to
    NCSE-02, Section 2.4, corresponds to a coefficient of 1.6. Actually it should
    take into account all the strata of the land located 30 meters below the support level 10, but in the absence of more data, we will keep this one. Coefficient of amplification of the land (S), according to NCSE-Q2 2.2 is valid:
    b
    s ~ ~ + 3.33. (p a -0.1) '(1 - ~) EC. 7
    1.25 9 1.25
    1.6 (0.11) (1.6)
    S ~ - + 3.33 · 1, - 0.1. 1 --- ~ 1,271 EC.8
    1.25 9.8 1.25
    Thus, the seismic acceleration will be worth:
    ac = S 'p' ab = 1,2711. 0.11 = 0.1 40 EC.9
    Period and vibration modes
    For the building response model, it is also necessary to know the characteristic periods 20 of the response spectrum, TA and TB, which are valid (NCSE-02 2.3):
    K 'C 1 1.6
    TA = - ~ - = 0.16 EC.10
    10 10
    K 'C 1 1.6
    = - ~ - = 0.64 EC.11
    TB
    2.5 2.5
    The fundamental period of the building for the case of rigid rolled steel frames takes the value of TF = 0.11 n, being ~ the number of floors of the building. Therefore, our fundamental period is TF = 0.11 s. The response spectrum value (a) is a function of the period o = o (T), and for values

    Below aTA is equal to 1 +1, 5 TfT A, which in our case is:
    0.11
    a (O.l1) = 1 + 1.5. - = 2.03 EC.12
    0.16
    A single vibration mode will be considered, since TF is less than 0.75 s (NCSE-02 3.7.2.1).
    Response Coefficient! 3
    This coefficient depends on the behavior of the building in case of earthquake, and is given by Table 3.1 of the NCSE-02 depending on the level of ductility adopted by the designer.
    10 The level of ductility depends on the way in which the structure resists horizontal actions. In the + XI-X direction, our ship resists horizontal actions by means of rigid knot frames, thus corresponding to a very high level of ductility (1J = 4).
    In the perpendicular direction, it resists them by crossing San Andrés, thus corresponding to a high level of ductility (IJ = 3). Simplifying, and on the side of security, we will remain with the most unfavorable value (IJ = 3). According to Table 3.1 of the NCSE-02, the response coefficient will be ~ = 0.36.
    Masses involved in the calculation.
    20 Equivalent static forces depend on the masses of each floor of the building. In the case of our ship, the only plant it has is the roof, and its masses to consider in the calculation are: Own weight: considering the weight of the belts and lintels, we can approximate it to about 0.30 kN / m2 •
    25 Permanent loads: the only permanent load we have is the weight of the covering material: 0.09 kN / m2 • Snow overload: not being applied more than 30 days, it is not necessary to take it into account. Overload of use: maintenance use is not included within the masses at
    30 take into account in the calculation (NCSE-02 3.2).
    Therefore, the mass to be considered will be 0.39 kN / m2, which referred to the tax area of each portico (each load will be applied to one of the upper nodes of the portico):

    512
    60.B3m2 EC.13
    cos 9.46
    0.39kN Pt = 60.B3m2 • 2 23.72kN EC.14
    m
    The mass of the enclosure walls is not considered acting on the supports due to constructive considerations, since it has been observed that there are usually no rigid links between them and the supports, so interaction will not occur.
    Static Equivalent Forces
    A horizontal load equal to:
    EC.15
    0.149
    FI = - '23.72. one . 2.50 '0.36 = 2.99kN
    EC.16
    9 10
    Where: 01 takes the value 2.5 as the calculation period (T) is less than TB. 111 is the distribution factor, which depends on the height of the plant considered in relation to the total building. For one-story buildings, it takes a value equal to the
    15 unit
    The resulting load per gantry is negligible when compared to the wind load + x. In addition, the seismic load is considered accidental, and therefore has much less weight in the calculation of the structure, as the safety coefficients that are applied are much lower
    20 in combinations of this type. So in our calculation the seismic load will not be taken into account.
    2. Design and calculation stage
    25 2.1. Actions by Thermal Load
    In our case we can meet various situations. In reality the thermal load will depend on the location of the ship with respect to the total set of ships that
    They share the same structure.
    In this way, even if we find a ship or set of them, which has expansion joints at a distance less than or equal to 40 m, although the displacement of the structure is really allowed, this displacement is not completely free, but rather each lintel-pillar joint would behave as if it had a spring with a certain elastic constant.
    In our case, in order to get as close as possible to reality, we should study the set of ships that share the structure. For this, it has been considered that as the length of continuous structure to disregard the thermal load is 40m, it would be equivalent to 3 ships of 12m of maximum light (3x12m = 36m), which on the other hand is a very common case in the construction of ships with shared structure.
    For this, the following parameters will be taken into account:
    The reference temperature shall be 10 ° C, as indicated in section 3.4.2. of the
    DS SE-AE.
    A minimum temperature of _6 ° C will be taken for the city of Malaga (section 2,
    Schedule E of DS SE-AE).
    The maximum temperature shall be 48 ° C (section 1, Schedule E of the SE-AE DB).
    An interactive calculation program for flat structures "CESPLN carried out and registered by Mr. Juan Tomás Celigüeta, in collaboration with the Higher School of Engineers of San Sebastián, University of Navarra, has been used to verify the structure. Version 5.01 will be used, It is freely distributed and has been downloaded from the TECNUN website of the Higher School of Engineers of the University of Navarra: hltp: IIwww1 .ceit.as / asianatu ras / Estructuras 1 / P rOaramas. htm.
    The CESPLA program (Calculation of flat structures) performs the analysis of flat reticular structures of any type, such as lattices, porches or beams. The program uses the method of rigidity, for its simplicity of programming and generality and is based on the theoretical foundations explained in the book Structural Analysis Course (Juan Tomás Celigüeta, Ed. EUNSA). In fact, this program is a complementary element for the reader of said book.
    2.2. Study of steel structure against fire.
    To study the behavior of a steel structure in the case of a fire, the provisions of Chapter XII of Royal Decree 751/2011, of May 27, which approves the Structural Steel Instruction (EAE-) eleven)
    This chapter establishes the criteria to be applied in the project of steel building structures to verify their bearing capacity under the action of a fire, considered as an "accidental situation", for structural safety purposes.
    The action of fire or thermal action is defined by the heat flow that affects the surfaces of the structure elements exposed to fire. Depending on the "calculation fire" adopted, the following procedures should be used:
    With the standardized time-temperature curve defined by CTE, the thermal analysis of the structural elements is carried out for a specified period of time.
    With another fire model, the thermal analysis of the structural elements is carried out for the complete fire process.
    The procedures for checking the safety of steel structures against fire explicitly included in the aforementioned Instruction belong to the category of calculation models classified as "simplified", which are calculation methods based on appropriate assumptions for application to elements Simple structural, or small subsets of them.
    Calculation Fire
    For each calculation fire scenario a calculation fire is considered in a fire sector, in accordance with section 3 of the UNE-EN 1991-1-2 Standard. The Gc coefficients applicable to the standard time-temperature curves are indicated in
    A8.3 of the EAE, defined by the calculation fire chosen.
    Element surface temperature [oC]. It is obtained as a result of the thermal analysis of the element according to Chapter XII relative to the structural calculation in a fire situation.
    <l> Form factor; if specific data is lacking, <l> = 1.0 must be adopted. In order to have
    considering the effects of position and shadow, a lower value can be adopted.
    Em: Emissivity of the surface of the element, m = 0.7 will be adopted.
    AND! Emissivity of fire; E is usually adopted! = 1.0
    Gas temperatures of the fire sector 0B can be adopted in the form of
    Nominal time-temperature curves conforming to A8.3 of the EAE, or according to the natural fire models indicated in AS.6 and AS.7. Among the nominal time-temperature curves, in addition to the standardized UNE-EN 1363 curve, the external fire curve can be used to characterize the less severe fires produced in exterior areas adjacent to the building, or to measure the effects on external elements of the Flames coming out the windows.
    For the present study, only a simplified fire model will be used, so for5 To obtain more information on this type of fire model, we should go to what is indicated inSection 3.3.2. of Standard UNE-EN 1991-1-2: 2004.
    Calculation of temperatures in steel
    10 For the calculation of the temperature in steel, the provisions of section 48 of Royal Decree 751/2011, of May 27, which approves the Structural Steel Instruction (EAE), shall be taken into account.
    Unprotected items
    EC.17
    p¡¡, C¡¡ Density and specific heat of steel defined in section 45.1 of the EAE expressed in kglm3 and JI (kgOK) respectively. As indicated in the following section a specific heat will be taken for simplified procedures, which will be
    20 independent of the temperature, taking a value of C¡¡ = 600 J / (kgOK) For the density of the steel a value of p¡¡ = 7850 kg / m2 will be taken
    • Elements with protective coating
    p¡¡¡¡¡
    Density and specific heat of the steel defined in the section
    45.1 of the! :: AE expressed in kg / m3 and J / (kgOK): c, = 600 J I (kgOK)

    For the density of steel, a value of:
    p, = 7850 kg / m '
    List of total heat capacities of the coating and
    of the steel element, in cases a) and d) of section 48.3 of the EAE
    EC.19
    Values of calculation of the specific density and heat of the coating according to 48.3, in kg / m3 and J / (kgOK).
    r p.ef.d = r p.ef, kfYp Calculation value of the effective thermal resistivity of the coating, in m2 ° KNV, with Ypdado in 48.3 of the EAE-11
    rp, ef, k = (1 + cpf3) dpfApk Characteristic value of the effective thermal resistivity of the
    coating, in cases al and dl of section 48.3. from the EAE
    r p, ef, k Value determined according to 48.4, in cases b) and d) of section
    48.3 of the EAE-11.
    Gas mass temperature (oC) defined in 43.2. of the EAE-11.
    Variation of the mechanical properties of steel in case of fire
    For fire resistant checks, Y M, fi = 1, shall be adopted as
    5 partial coefficient for steel strength.
    For application in the resistant test procedures defined in Chapter 13 of the EAE-11, the following corrective coefficients of the mechanical characteristics of the structural steel must be adopted, depending on the temperature reached by the
    same (ea):
    Ky, e Quotient between the effective elastic limit for temperature (ea) and the

    elastic limit at 20 oC.
    EC.20
    Ke.s Quotient between the modulus of elasticity in the linear phase of the stress-strain diagram, for temperature (ea) and the modulus of elasticity at 20oC.
    EC.21
    The values of these coefficients are taken from Table 45.1 of the EAE-11, which allows linear interpolation. The application of these coefficients is valid if the simplified calculation models of steel temperatures included in the Instruction are applied, or
    5 other procedures supported by it, but in this second case it must be verified that the temperature increase rate is maintained between the limits 2 SdsJ dt: S 50 ° C / minute.
    In simplified procedures, a linear relationship between expansion and temperature can be considered using the coefficient:
    10 a, = 14 x10 · '(9, -20)
    Likewise, in simplified procedures the specific heat can be considered independent of the temperature, taking the value:
    e, = 600 J / (kg'K)
    15 and the temperature independent thermal conductivity can be considered, taking
    the value:
    Aa = 45 W / (m 'K)
    20 Although the standard gives characteristic values for each protective material, it is possible to take into account real values such as those provided by the manufacturers themselves in their tests.
    2.3. Weakening method by decreasing the profile section
    25 In previous sections, all the actions that can act in a building have been calculated, in order to be able to evaluate them, to be able to make the corresponding checks and thus, to be able to justify that it complies with the provisions of the EL Among all the hypotheses, it will be studied, with the help of the mentioned program 34
    CESPLA, which was described in the section of actions for thermal loads, only the most unfavorable, since they are the ones that will determine the compliance, or not, of the structural safety.
    As what is sought is to justify that the failure of a structure in case of fire does not affect the structures of the adjacent ships, we find 2 well-differentiated cases and that it is understood that they should be studied separately, since this is going to depend on the choice of the hypotheses studied previously:
    Case 1: ship attached to other ships on both sides with shared structure.
    • Case 2: ship attached to another ship only on one side, being in contact with the outside on the other.
    gravitational loads have a value of 0.6 kN / m2, as indicated above.
    Because the structure is to be taken for granted, and of a certain age, it will be considered that the structure will be formed by A42b profiles, although the calculation process with current profiles is identical, since the variations in their mechanical properties are made by coefficients, as seen in a previous section.
    Given the wide variety of cases that can be studied, a criterion for numbering them will be stipulated below, so that by looking at the number that corresponds to each case, one can perfectly know what the conditions are. Thus, a case called ~ Case 1-2-60-3-3 "would mean" Case of a ship attached to both sides, with the structure weakened according to option 2 and with an elapsed time of 60 minutes of fire, 3 cm of protection on the lintel and 3 cm of protection in the weakened area. "Since the study, which is represented in this work is different for each type of ship that can be found. And the objective of the study is to serve as a guide to be able to study each singular case that can be presented, it will only be studied case 1, that is, ships attached to both sides; particularly cases 1-0-0-3-0 (based on which the less requested areas of the lintel are determined, suitable for weakening), 1-3- 90-3-1.5 (in which there is an increase in tension by Van Mises but still below the elastic limit), and 1-3-90-3-1.5 (in which this elastic limit is already exceeded ).
    In relation to the weakening options analyzed, there are three:
    Option 1 (figure 18): To weaken the profile, begin by trimming the wings
    bottom of it, a distance of 3 cm on each side, so that the edge
    The bottom of the IPE would measure 6 cm instead of the 12 cm of the standardized profile, as
    It is shown in the following figure.
    • Option 2 (figure 19): In order to weaken the profile much more in the modified area, it is decided to make a more drastic cut in the geometry of the latter. from
    so that it is as follows.Option 3 (figure 20): In order to be able to weaken somewhat less the pertil in the area
    modified, it is decided to make a smaller cut in the pertil, so thatIt is as follows.
    In accordance with the above, we now proceed to comment on the different cases studied.
    Case 1-0-0-3-0: ship attached to both sides. structure without weakening. without fire 3 cm of 10 protection throughout the lintel
    The way to study in this case will be the most unfavorable of those studied in the section of calculation of the actions in the chosen model structure, that is, mode 5, but without lateral wind + thermal load under conventional conditions (Figure 21).
    15 From these data we calculate the linear loads on the gantry, which are represented in Figure 22:
    0.381kN 101.97kg 1m ---.-------, - ,, --- "-. Sm '1.94kgjcm
    2 EC.22
    m kN lDDem
    0.49 Ok N.:. 10 ::.: 1:;:. 9: -; 7.::k,,-g 1m
    . Sm '2.50kg / em EC.23
    m2
    kN 100em
    0.600kN 101.97kg 1m m2 kN 'Sm' lDDem 3.D6kg / em EC.24
    With this data, the model is introduced in the structure calculation program, 20 obtaining the bending, cutting and deformation moments referred to in tables 12 and
    13.
    Due to the fact that said program does not provide partial data of the complete bar of the portico with sufficient detail, the lintel has been divided into segments of approximately 1 m in length, and the loads indicated in Figure 22 have been introduced.
    25 considered a thermal load corresponding to the maximum temperature in the province of Malaga, of 48 ° C (section 1, Schedule E of DB SE-AE).
    As indicated above, the mathematical model of said program to calculate the effects of thermal loads, consists in considering that this load is due to a linear variation of the temperature at the edge of the bar, and therefore is defined for his
    30 average value and its gradient along the edge. These temperatures are assumed to be uniform throughout the entire length of the bar, as indicated in section 4.2 of the UNE-EN 1993-1-2 Eurocode 3: Steel structures project.
    Because both existing and new structures, usually have constructive solutions called cartels, at the junction of the pillar with the lintel, and since program 5 does not allow the introduction of a variable section bar with respect to the x axis, it is decided for the introduction of a bar in the "segment 2 and 13M of a larger film, in our case an IPE-300, a consideration that would be on the side of security, since due to the geometric characteristics of the cartouche, these have mostly part of the length a larger section, in addition to the option chosen causes increased effort in the
    10 bars3 and 12.
    CASE BAR 3BAR 4Pilar-lintel deformationDeform. Max.Adm. Pilar-Lintel cm (L! 250)Do you meet
    Axil ksfcmJ Shear kg! CmJVon Mises kg! CmJAxil k8lcmJShear kg / cmJVon Mises k8lcm>
    51N DEBILI TAR
    1-0-0-3-0 -1173.68130.421195.22-524.13 102.20553.210.672.80YES
    Table 12
    CASE BAR 12BAR 11Pilar-lintel deformationDeform. Max. Adm. Pilar-Dintel cm (L! 2SO)Do you meet
    Axil ksfcm ' Shear kafcmJVon Mises kg / cm>Axil ksfcmJShear kg / cm>Von Mises kg! CmJ
    51N WEAK
    1-0-0-3-0 I-1113.97 136.28 1138.70-440.69 104.87 476.660.592.80YES
    Table 13
    As is already known, the shear values are insignificant with respect to the beaver, and as can be seen in the corresponding data tables, these values are irrelevant.
    20 It is clear from the data obtained that bars 4 and 11 are the least requested areas of the lintel, so a priori this would be the ideal area to do some weakening of the profile, since, in the most usual case (in which the section is constant throughout the entire bar) it is the area in which a reduction of the section compromises to a lesser extent the safety of the bar for any conditions of use compatible with the
    25 existing at the time of analysis. In the same way, both the minimum value of bending moment and tension by the Van Mises Criterion occurs in bar 3.
    Case 1-3-80-3-1.5: ship attached to both sides. Weakened structure -option 3. 80 minutes of fire. 1.5 cm of protection in the weakened area and 3 cm of protection in the rest of the
    lintel
    Table 14 shows the temperature values at 80 minutes with 1.5cm of protection in the weakened area and 3 cm of protection in the rest of the lintel.
    Profile Oisposi-CiónExposed perim (m)Section (M 'IThickness protection (cm)T 'Steel t ~ c)Mod. The ast icity Kg / cm 'Elastic limit Kg / cmz
    IPE-HO Pillar0.14820.00459374.962,100,0002600
    IPE-240 LINTEL0.92200.003913255.831,772,7512600
    IPE-300 LETTER1.16000.005383241.771,802,2892600
    IPE -240 Weakening 3 DI NTEL0.62090.0024871.5496.81,266,7282600
    Table 14
    With these values and the help of CESPLA, we obtain the values referred to in tables 15 and 16.
    Deform.
    BAR 3
    BAR 4
    Mu_Adm deformation.
    Pilar-lintel
    Pillar
    Do you meet
    CASE
    Alil
    Cutting
    Von Mises
    Cutting
    Von Mises
    "'"
    (cm)
    Lintel cm
    kg / cm '
    kg / cm '
    kg / cm '
    kg / cm '
    kg / cm '
    kg / cm '
    1l / 250}
    WEAKNESS OPTION 3 1-3-80-3-1.5 I -1082.87 I 122.81 I 1103.56 I-2123.40 I -183.37 I 2147.02 I 2.38 I 1, SO I YES
    15 Table 15
    CASE BAR 12BAR 11Deformadon Pilar-lintelDeform. Max.AdmPilar-Dintel cm (l / 250). CUM PLE
    There! kg / cm ' Shear Von Mises kg / cm 'kg / cm'Axil Corton Von Mises kg / cm 'kg / =' kg / cm '
    WEAKING OPTION 3
    1-3-80-31.5 -1067.86130.26 1091.43-1890.3 191.64 1919.292.262, SO I YES
    Table 16
    It is observed that the tension has increased by Van Mises, but it is still below the elastic limit 20. The displacement of the pilar-lintel nodes continues to increase.
    Case 1-3-90-3-1.5: ship attached to both sides. Weak structure - option 3. 90 minutes
    of fire 1.5 cm of protection in the weakened area and 3 cm of protection in the rest of the lintel
    The temperature values at 90 minutes with 1.5cm of protection in the weakened area and 3cm of protection in the rest of the lintel are shown in table 17.
    Profile Oisposi-CiónExposed perfometer. Im)Section (M ')Thickness protection. I, mlT 'Steel. elevenMod. The ast icity K¡ / cm 'elastic limit K¡ / cm '
    IPE-270 PILLAR0.14820.00459381.402,100,0002600
    IPE-240 DI NTEL0.92200.003913288.541,704,0772600
    IPE-3oo LETTER1.16000.005383272.651,737,4262600
    IPE-240 Weakening 3 LINTEL0.62090.0024871.5546.06979.5051656
    Table 17
    With these values and the help of CESPLA, we obtain the values referred to in tables 18 and 19.
    Deform.
    BAR 4
    DeformKlón M ~ l (.Adm.
    Pil ~ r · d¡ntel
    Do you meet
    Pil ~ f
    Cut off
    Van Mises
    (cm)
    Lintel cm
    Ic, g / cm '
    k¡ / cm '
    ka / cm '
    'I / 2SO'
    BAR]
    CASE
    Cutting
    Von Mises
    ""
    Ic, g / cm '
    "'~.
    "'~.
    WEAKNESS OPTION 3 1-3-90-3-1.5 I -1034.84 I 121.54 I 1056.03 I-1912.84 I -180.91 I 1938.33 I 2.64 I 2.80 I •
    15 Table 18
    CASE BAR 12BAR 11OefOfm ~ clone Pil ~ r-dlntelDeform. Mall. Adm. Pilar-Dintel cm 'I / 2SO)Do you meet
    "'' 'k & / cm' Cort; Jnte k & / cm 'Von MiH5 kelcm ' "'' 'k & / cm'Cut off '' ~.Von Mises ks! Cm '
    OPTIONAL WEAKENING]
    1-3-90-3-1.5 1-1039.29 129.68 1063.28-1756.52 I 190.53 1787.252.51 I 2.80•
    Table 19
    It is found that both the bar 4 and the bar 11 exceed the elastic limit of the weakened zone, which, as indicated in the previous table of parameters of the material as a function of temperature, was 1656 kg / cm2 •
    Thus, it is observed that the following conditions are met: The only point where the elastic limit of the material is exceeded and therefore where the structure would collapse is in the weakened area.
    The collapse occurs after exceeding 60 minutes required by ROYAL DECREE 2267/2004, of December 3, which approves the Regulation of
    Fire Safety in Industrial Establishments.
    At the moment when the structure collapses, the displacement of the nodes of the 5 pillar-lintel joints has a deformation less than the maximum indicated in the section
    4.3.3.2. of the DB-SE of the CTE on horizontal displacements. This section indicates that when considering the appearance of the work, it is admitted that the overall structure has sufficient lateral stiffness, if in the case of any almost permanent combination of actions, the relative collapse is less than 1/250.
    It should also be remembered, as indicated above, the need to reduce the thickness of the protection to ensure that the temperature in the weakened area increases more rapidly, achieving that the elastic limit of said area falls earlier than in the rest of the structure.
    15 Once the results have been observed, the weakening option 3 is considered, and protecting the structure with 1.5 cm thick rock wool mortar in the weakened area and 3 cm thick in the rest of the porch, the conditions to be able
    affirm that the collapse of the structure of the ship under study in case of fire would not affect the adjacent ships nor compromise the sectorization with respect to them.
    Conclusions of the weakening method by decreasing the peml section
    Although at present, administration technicians, as a general rule, require that the materials used for passive protection, and that they are called "marked with 25 CE ~ must meet at least the thickness indicated in the tests carried out by the manufacturers themselves, in this case, and given the nature of the research study that this work possesses, it is understood that such compliance would not be necessary, since analytical calculations are made for the calculation of the temperature of the steel in case of fire with normalized fire, using thermal conductivity data for them, heat
    30 specificity and density provided by the manufacturer in its product data sheet. In this way, it is intended that the present study can become a possible reference when it comes to designing an alternative study of passive protection in industrial establishments.
    Despite what is indicated in the previous paragraph, it is necessary to insist that the only area that is going to have a thickness less than that indicated in the tests provided by the manufacturer, is in the weakened area, this area being no longer than 10 cm, in addition to counting
    with a time margin of approximately 30 minutes, since the weakened area collapses in the minute near 90, when what is required is 60 minutes of fire resistance.
    Therefore, as indicated above, it is demonstrated that the behavior of the structure in case of fire does not impair the stability or other conditions of the adjacent ships, because the deformations are less than the maximum allowed by the CTE, by what can be affirmed that the sectorization with respect to the adjacent ships is not compromised by the collapse of the structure. This statement is extended to both the establishment's delimiting walls, as well as to the possible strip of fires for the sectorization by roof, since this strip is usually fixed by screws to the wall itself, and not to the roof structure, method , which on the other hand, is the one indicated in the tests of the main manufacturers of materials for passive protection.
    2.4. Screw use method as thermomechanical fuse
    For the calculation of the union, the first thing we should do is decide where it is going to take place. For this we will start from the case of a mediator ship on both sides,
    structure without weakening and fire situation at 60 minutes.
    We are faced with two ways of making the union, one through a recessed union and the other through the creation of a kneecap. In order to assess which of the two solutions is better, we will proceed to study both cases. In the same way, each case must be studied for the 60-minute fire situation and the fire-free situation, always complying with Royal Decree 75112011, of May 27, which approves the Structural Steel Instruction (EAE).
    2.4.1. Recessed Union
    By establishing a recessed joint between the dummy bars 3 and 4, as outlined in Figure 23, it can be considered that the screws are placed in the fibers hardest by normal stresses (both by the effect of the axial force and by the effect of the fctorial force , of small magnitude at that point of the bar).
    Taking into account the distribution of tensions in a section subjected to f1ector effort (and low shear) according to the estimates of Navier's law (figure 24), it is reasonable to assume that the normal tension due to the fctorial effort to be supported by the short piece (screw or similar) that guarantees the behavior of the union, will be the maximum derived from the calculation for the section considered.
    To the tensions derived from the bending effort, those of the Axil must be added (figure 25), so that, for the purpose of normal tensions, the values obtained must be added or subtracted
    of the calculation, depending on which part of the section is being considered and how the fault is idealized.
    In accordance with the law of Colignon, which predicts the distribution of tangential tensions along the section of the bar, the situation of the screws in that position makes them very little susceptible to the effect of tangential tensions (null at the contour points and highs in the center) so that its effect can be considered negligible without undermining the security of the junction point.
    It is necessary to indicate that the cutting of the piece is not going to be made perpendicular to the direction of the axis (which would be logical for calculation purposes), because in that case the geometry could make it difficult to collapse the bar after the screw runs out, which is especially palpable in the case of the articulated joint that will be seen in a later section.
    It seems sensible to assume that the failure of the joint will respond to what is represented in Figure 26, which is equivalent to admitting that the failure will be due to maximum traction. Thus, it is evident that the maximum tension that will trigger the failure is the sum of the traction due to the effect of bending effort more or less those of the axil (depending on whether it is
    traction or compression in that section of the bar). In favor of safety it would be reasonable to neglect compression stresses if there is such an effort in the bar.
    Recessed union with fire
    The most unfavorable normal stress values, in the case of fire at 60 'and mediator on both sides, extracted from CESPLA are represented (bars 3 and 4) in Figure 27 (A and 8, respectively).
    Being significantly higher in bar 3 (specifically in the encounter between bar 2 and 3). But this way of offering the data is not very useful in this case, since it does not allow to choose a more specific point of the section of the bar in which to establish the union.
    To further specify the state of stresses acting on the screw, the stress values of the calculation program can be extracted (Figure 28), and the tensions can be determined ~ manually ~ at a more specific point (actually the one desired from the many that test the program).
    According to the values obtained, the point to study will be the one located at local X = 101.4 (of the dummy bar 4), corresponding to a bending moment of -6220.73 kg'cm and an axial effort of 2267.11 kg (in compression). By means of Navier and admitting a uniform distribution of the normal tensions by axial effort, the following tension values would result:
    N -2267.11kg
    (JN (pOr axial) = - = 2 -57.9 kg / cm2 (compression) EC.25
    39.1 cm
    - 6220.73kg cm. 2
    Max
    (1M = (navier) = - = 3 -19.21 kg / cm (compression) EC.26
    Wmax 324 cm
    We have not considered the angle of the roof, since the slope of the roof is very small, of the order of 9.46 °, which gives us a practically equal tension value and always less than that obtained through the expressions used, considering that is on the side
    of security.
    As what is desired is to dimension at that specific point (301.4 cm from the end), it will be necessary to verify what happens in the case in which the fire has not yet been declared and do so for the most unfavorable case by adopting the appropriate coefficients of security
    10 that will be seen later. In that case, as already indicated, the compression tension value would be neglected, since, by virtue of the breakage model already mentioned, the screw will not handle it.
    15 Recessed union without fire
    For this case, structure without fire and mediator on both sides, the stress values obtained with the CESPLA can be seen in figure 29. In the previous figures it can be seen that the point of least bending effort is the
    20 located 301, 4 cm from the end. In addition geometrically and for reasons of execution, it is not advisable to place the weakening near the fire barrier that is necessary to install for the sectorization by deck with the adjacent ships. So for the point located 301.4 cm from the end we have an Axil effort of 1844.37 kg (compression) and a bending moment of 5984.4 kg · cm.
    25 The voltages are calculated in the same way as for the previous case:
    N -1844.37kg
    (JN (by axil) = - = 2 -47.2 kgjcm2 (compression) EC.27
    39.1 cm
    Mm =: 5984.4kg. cm. 2 (JM = (navier) = = 3 18.5 k9 / cm (traction) EC.28 W "lUX 324 cm
    As indicated above, the angle of the roof has not been considered, since the
    The slope of this is very small, of the order of 9.46 °, which gives a voltage value practically equal and always less than that obtained by means of the expressions used, a consideration that is on the side of safety.
    It is observed that the tension due to the beacon for the local X = 301.4 cm is somewhat higher for the case with fire.
    Screw dimensioning
    For the dimensioning of the screw, we will consider the case without fire, since in this
    10 case the union works by traction, while in a fire situation at 60 minutes, the union works by compression, as we saw in the previous section. Given this, it should be clarified that, what is involved, it is to ensure that the joint resists at a tension level and that its operation will not be due to breakage but due to loss of the mechanical capacity of the screw due to temperature.
    15 For this we will rely on everything indicated in Royal Decree 751 12011, of May 27, which approves the Structural Steel Instruction (EAE). The screws that can be used for the purposes of said Instruction in joints of steel structures correspond to the degrees set out in Table 20, taken from the aforementioned instruction, with the specifications of elastic limit f and b, and tensile strength fub that in it
    20 indicate.
    Kind Ordinary screwsHigh strength screws
    Grade 4.65.66.88.810.9
    r. 240300400040900
    loo 4005006008001000
    Table 20
    25 Likewise, this standard indicates that screws of a grade less than 4.6 or greater than 10.9 shall not be used without documented experimental justification that they are suitable for the connection to which they are intended. It also states that they must be manufactured with materials that comply with the provisions of 29.2. They can be used as non-prestressed screws or prestressed screws (in the latter case, they must meet the requirements established in this regard in
    30 said standard). For this reason, the screw must not necessarily be made of steel, but may be made of another elastic material, which meets the elastic limits and minimum tensile strength required in the previous table. The type of material that is finally used will be the purpose of another section of this study.
    Bolted joints are classified, according to the way the screws work, into five categories. Three of them correspond to joints in which the screws are requested in the normal direction of their axis, categories A, B and C; and two others, categories D and E, to
    5 joints in which the screws are requested in the direction of their axis, that is, tension.
    In our case, the type of joint that we have to calculate is one of those defined as type D in the reference standard (ordinary screws working on tension). Section 5.7 of the aforementioned standard establishes the basis for estimating the tensile strength of a requested screw in the direction of its axis (both the tensile strength of the screw and the
    10 puncture resistance of the joint plate). This calculation is therefore useful for the screws indicated so far, intended to formalize a rigid joint at the point where the programmed system fault is established. The tensile strength of the screw is obtained from this expression:
    EC.29
    YM2 being the partial coefficient for the last limit state defined in table 21 taken from section 15.3 of the SEA.
    Resistance of the tron3vel'3ole3 sections. yw = 1.05 (1)
    Resistance of structural elements against instability. ) . 11 = 1.05 (1). (2)
    Breaking strength of traction cross sections. ) Y2 = 1.25
    Strength of the joints. ) 02 = 1.25
    Slip resistance of joints with prestressed screws: • In the ultimate limit state (joints category C) (see sections 58.2 and 58.8). . In the service limit state (..... heating ions B) (see sections 58.2 and 58.8). ) W = 1.25) toO = 1.10
    In our case YM2 will have a value of 1.25.
    fUb is the tensile strength established in 29.2 of the EAE, which will have a value of 400, 500 and 600 N / mm2 for ordinary screws of grade 4.6, 5.6 and 6.8 respectively.
    The tension to be taken into account, as we saw, was due to the bending moment, because the one corresponding to the axial effort was compression and that therefore we were going to despise, because the screw was not going to take care of this tension.
    The effort therefore to take into account is that of the bending moment Mf = 5984.4 kg'cm, which in the furthest fiber will give us an effort of
    5984.4 kg cm Ft Rd = = 498.7 kg = 4 886.9 N EC.30
    . 12 cm
    In this way it is obtained that the tensile strength of the screw, initially considering an M12 screw with an initial section of the 84.3mm2 screw, will be:
    mm
    O.9 · {ub · As or. c.: '9 _'_ 4 "O ..: O ..: N" /c..m ",, m: ..'_' ..: 8 ..: 4",. 3.c. :: C.:...'
    - = 24,278.4 N> 4886.9N
    Ft.Rd =
    1.25 EC.31
    YM '
    - + if valid
    In addition, it should be borne in mind that the effort would be divided between two screws, each one located on both sides of the soul.
    If a screw of material other than steel was used, which in any case must be isotropic, we could calculate the tensile strength that the screw must have, depending on the tension to which the joint is subjected, and which we had calculated in previous section.
    If we use the above formula, we can calculate the minimum tensile strength of the screw, in order to take into account the safety coefficients given by the standard. We will also start from a section of the M12 standardized screw:
    [, _ Ft.Rd. YM2 4886.9 N · 1.25 N
    80.5--, = 822 k9 / cm '
    ub -0.9 'As 0.9' 84.3mm2 mm EC.32
    Therefore, this would be the minimum tensile strength that the material forming a hypothetical M12 standardized screw should have.
    However, once the material has been chosen, the procedure should be carried out again to verify that the screw section is adequate. Keep in mind that the effort will be divided between two screws, one on each side of the soul.
    The puncture resistance of the sheet is obtained from this expression:
    Bp.Rd = O, Slrd, Jfu
    EC.33
    r M2
    The average diameter between the circumscribed and inscribed circles of the nut / head and 5 was the tensile strength of the sheet steel. It is not necessary to check the puncture resistance if the sheet thickness verifies at least:
    EC.34
    Being:
    10 tmin = minimum sheet thickness. d = diameter fUb = minimum tensile strength of the screw (table 29.2 EAE). lo = tensile strength of the steel sheet (table 27.1 EAE).
    12mm '400 N / mm2
    t - = 1.86 mm EC.35
    mm 6. 430 N / mm2
    Therefore, it seems sensible to adopt this condition for the thickness of the end plates of the film.
    2.4.2. Articulated Union
    20 For the articulated joint, we can perform the joint as illustrated in Figure 30, a situation in which the screws can be considered to be located in the fibers hardest by shear stresses.
    25 Joint articulated with fire
    The most unfavorable tangential stress values, in the case of fire at 60 'and mediator on both sides, extracted from CESPLA are represented (bars 3 and 4) in Figure 31 (A and 8, respectively).
    The stress values obtained with the help of the calculation program are referred to in Figure 32
    Articulated joint without fire
    The most unfavorable tangential stress values, for the case without fire and mediator on both sides, extracted from CESPLA are represented (bars 3 and 4) in Figure 33 (A and 8, respectively). The effort values obtained with the help of the calculation program are represented
    10 in figure 34.
    Screw dimensioning
    For the dimensioning of the screw to shear, we will consider the case without fire.
    15 For this, as we did for the recessed union, we will rely on everything indicated in Royal Decree 751 12011, of May 27, which approves the Structural Steel Instruction (EAE).
    The shear resistance (sliding) of the screw is obtained from this expression (section
    58.6 EAE):
    0.6 f ", An
    F:. RJ C.36
    YM2
    Where:Fub = tensile strength of the screw in N / mm2 •A = Screw shank area in mm2
    25 n = Number of possible gliding planes; in general it will be n = 1 or n = 2. In the case at hand, there is only 1 plane. YM2 the partial coefficient for the ultimate limit state defined in section 15.3 of the SEA.
    30 To choose the appropriate material, the procedure must be by repetition, that is, by choosing a material taking into account the shear stress to which it must be subjected, and the temperature at which the screw will be in the 60th minute of fire, it is from here that the material should start to fail, that is, when the maximum service temperature should be reached.
    Because the temperature of the screw will depend on the specific heat of the material used for its preparation, it is necessary, once the material is chosen, calculate the screw temperature in the 60th minute of fire, and check that:
    In said 60 minute of fire, the screw temperature is below the
    maximum service temperature of the material.
    Once the fire minute has passed, the screw reaches the temperature
    maximum service of the material before the temperature of the steel that forms the
    structure causes deformations in it that can cause faults in the
    sectorization with adjoining ships.
    As can be seen in the previous section, the shear stress for the point 301.4 cm from the end is:
    F•. R '= 1318.37 kg = 12920 N EC.37
    It is considered that this solution by means of articulated joint is more suitable than by embedding, due mainly to the fact that the fault would be sought in 2 elements (screws) instead of 4, its execution being simpler, although it could perfectly be studied also by recessed union. For this reason, in the present study, and once we choose the material, only the solution will be studied through articulated union.
    Choice of Screw Manufacturing Material
    For the choice of a suitable material, the material database of the application "CES Selector Version 5.1 .0 ~ made by the company GRANTA DESIGN LlMITED (www.grantadesign.com) has been used.
    Use of CES for the selection of materials
    CES is a database of materials so extensive, that the choice of a material suitable to our needs, may seem, a priori, a very tedious work, and complicated to achieve without spending much time.
    Therefore, it is necessary to have a little knowledge of materials science, so that you can have from the beginning, a clear idea of what kind of material we can choose for our solution.
    The first thing to be clear about is that it is intended to join two pieces of steel, but in addition the joint element must not be of this material, because it is necessary to find a material that has an elastic modulus that behaves differently with the temperature rise. This condition is indispensable so that we can achieve the failure of the connecting element before the structure itself.
    If it is observed in previous sections, where the behavior of the steel elements has been seen with the increase in temperature, it can be seen that the modulus of elasticity falls from a certain temperature value, but instead the elastic limit does not vary until a much higher temperature of the element is achieved. This leads us to the conclusion that deformations occur in the structure before it can produce the same, and that is why we must look for a material that, on the one hand, supports the tensions to which it will be subjected, and on the other hand, that the elastic limit falls to a much lower temperature than steel, so that the joint element can make a true thermomechanical fuse.
    In addition to this, it should be borne in mind that the use of another type of metal other than steel can cause galvanic corrosion problems, unless a metal is chosen that has such a potential as steel, that the galvanic current is virtually negligible. In addition to this option, there are also methods to avoid such galvanic corrosion, such as:
    Electrically isolate the two metals by placing an intermediate insulator.
    Protect the most noble metal with plastic coatings and epoxy resins.
    Electroplating or electroplating techniques.
    Cathodic protection.
    As can be seen, these solutions are complicated in some cases to execute and in others they do not guarantee 100% protection over time, which would require maintenance operations.
    For these reasons, we will choose to find a material for the non-metallic joint element (which must also be isotropic), in order to avoid the problems described.
    That said, we can already limit the choice of material in a certain way:
    A priori, the aforementioned limitations related to galvanic compatibility and
    mechanical behavior depending on the temperature, suggest the use of a
    polymer.
    • The maximum service temperature, seeing the temperature of the steel in the 60th minute of fire, should be around 200 ° C. Of course, this temperature is only one orientation, because once the material has been chosen, which will have a specific specific heat, it would be necessary to calculate its temperature in the 60th minute, as was done with the steel. The connecting element is going to be protected with the same thickness as the rest of the structure, that is, with 3cm.
    5 If possible, we should look for a material with a specific heat similar to that of steel, so that the two materials increase their temperature over time at a similar rate. In addition, the material we use must be compatible with the projected rock wool, although this condition is easy to achieve, since this product is one of the most
    10 inert that exist then, is composed of cement mixed with volcanic rock wool.
    Once we have an idea of the material we are looking for, we proceed to search the CES database focusing on its mechanical and thermal properties:
    15 Initially we will limit the elastic limit, as it is the value that we will use to size the joint. Basically, depending on the elastic limit of the material, this will be the size of the joint, that is, the diameter of the screw. Discarded foams, and focusing on plastics, we know that the elastic limit will be between 3 and 230 MPa. In principle, the elastic limit between 40 and 230 MPa will be limited.
    20 Now we are going to limit the thermal properties of the material. We are going to focus on the maximum service temperature and the specific heat. Acting in the same way as for the elastic limit, we will see what ranges the different materials have within the polymers. We see that the maximum service temperature of plastics is in a range between 27 and 290 oC. so if it would fall within what we initially sought,
    25 provided the specific heat is more or less similar to steel. We will limit the maximum service temperature between 180 and 290 oC. For the specific heat, we see that in general, polymers have a much higher specific heat than steel, which is 460 J / kg K. For different types of plastics, the specific heat ranges between 940 and 2200 J / kg K. We will limit the specific heat between 940 and 1300 J / kg K.
    30 Of course, now we have a problem, and we have 3 parameters and only two coordinate axes, so we will have to initially choose between which two properties we want to do the search. In principle we are going to focus on the elastic limit and the maximum service temperature, and then we will verify that the specific heat of the chosen material is more or less adequate. According to this, we focus on plastics
    35 with a maximum service temperature between 200 and 270 oC and an elastic limit between 40 and 230 MPa.
    Among all the materials that could be chosen, we see that the main problem that plastics have is that they have a specific heat much higher than steel, because of this
    reason and lacking a plastic with a lower specific heat, the so-called 53% GLASS FIBER AND MINERAL PPS will be chosen, which, as its translation indicates, 5 is a polymer composed of 53% fiberglass and mineral whose properties include:
    Elastic limit: 139 MPa.
    Maximum service temperature: 290 oC
    Specific heat of the material: 1200 J / kg K
    10 Density: 1820 kg / m3 •
    Actually, the properties are given in some ranges, and as usually these materials are made to order. we should choose the value that. Within the range, more fit our needs.
    15 Next, the screw will be dimensioned and its temperature calculated in the 60th minute of fire.
    PPS Screw Sizing 53% GLASS FIBER MINERAL YEAR
    20 From the above data, we will clear the shear resistance formula in section 58.6 of the EAE. the screw section so that the safety coefficients established in said expression are taken into account.
    F .y
    A = v.Rd M2 -., ..,. 1-, 29., - 2, -O_N "._ 1., .. 2 .., 5_ = 1 9 4 mm2
    2 EC.38
    fub. 0.6 'n 139 N / mm. 0.6 '1
    ~~ EC.39
    D = ~ -; - = ~ ---; - = 15.7 mm
    25 In order to take a measure that could be standardized as far as possible, a diameter of 16 mm shall be considered. With these dimensions and with the properties obtained with CES SELECTOR, the screw temperature will be calculated.
    It has been considered that the entire area of the screw will be given a rock wool mortar protection of the same thickness as the rest of the lintel, that is, 3 cm. As indicated in 30 previous sections, the rock wool mortar is formed by a combination of rock wool with cement as the only hydraulic binder and other additives in small percentages
    incorporated into its manufacturing process. After consultation with the manufacturer itself, none of the components that make up the mortar is incompatible with polyphenylene or, of course, with fiberglass and mineral.
    For the calculation of said temperature the same expression used for the
    5 calculation of the temperature of the protected steel, as this is valid for any material, provided that its mechanical and thermal properties are taken into account. At the end of the day, this expression is a formula for calculating the transmission of heat to a material, taking into account its geometric and intrinsic properties.
    The results obtained are shown in table 22.
    DENOMlNAOON TORNIUO PP $ S ~ GLASS FIBER MINERAL YEAR
    DIAMETER mm
    "
    PERFMETER 1m) or, 05026SS m
    SfCCION 1m '} O, 0C0201 1 m'
    heat ~ sp ~ (graphical 1200 J / (qtK) (d ~ 1 mat ~ rI ~ 1 of the screw)
    Den ~ dad 1820 k & / m 'Id ~ 1 screw material)
    Factor Section ~ Iem. prole & -: Sp 250.00 m
    O, 05026SS m
    klh: coefldenl ~ d ~ coffecdón of ~ fecto 1.0
    rom '"
    ReYestivlmlento utllllado LANA OE ROCA
    Thickness rev ~ stiml ~ nto: d. O '"m
    Density coating: ~ 250,000 k & m
    caloresp ~ cif. Rev ~ st¡m: Cp 1200,000 JIIqVk)
    With <!. ToI.mla rnnvendon ~ l: A, .. O '"W / (mtk)
    1,0302
    (one',").' vilo <cl, act..kllco ct.11 'ffl! lIv1d1dWmlu elecll ... d.r. ~ LImlftlto
    coefid ~ nt ~ ~ rdaJsecurldad: V, '000
    h .ot,. = rp, d, k, lVp vilo <dell calculation'eslltl "' cl.1d" "mi., elective d., _tlmlftlto
    Table 22
    minute ° 10 20 30 40 SO 60 70 80! lO gas temperature see 36.00 678.43 781.35 841.80 884.74 918.08 945.34 968.39 988.37 1005.99"" .., 'C 36.00 7.59 3, n 2.51 1.88 1, SO 1.25 1.07 0.94 0.83A9a, t 'C -3,907 U96 ~ 842 2,987 2,979 2,904 2,797 2,673 2,542 2,409h, t OC 32,093 12,122 64,388 123,134 182,945 241,813 298,805 353,455 405,542 454,981
    Table 23
    OIAOMETRIC OENOMINATION EYE PPS s ~ GlASS f llllR YEAR MY NERAL "mm
    PER (MfTIlO (m) 0.0628319m
    SECOON (m ') 0.0003142m '
    J / (qtt: 1 (del mltl: rial del tom illo)
    Densl ~ "" 100.00k & lm 'm-'(from fNtl: rIaI cItol thyme)
    0,0 & 2S319 m
    Klh: o; oendentl: de Q) n'l: edón del efe (lo ~ m '"
    ! tewstlvlmlflnto used ROCK WOOL .. "m
    q / m '
    neo, "" .. '" J / (k¡t I.l W / (m'l ()
    ".., V.I ... eo'KlWhllco do l., ..I.lIit1Uti t_mleo ...., h. CIoI ._timl..1O o, n15
    r ... l.; r., or I.UYo · val ... cM <. Calculation cM la, .. ¡"h4 ... d * mI.> oI« ti ....,. ¡. _IIm1 ..... m'ptjw
    5 Table 24
    As shown in table 23, in the 60th minute of fire, the screw would be at a
    temperature of 298 ° C, so it would be above the maximum service temperature, the
    which, as indicated above, was 290 ° C.
    10 Since the temperature is really exceeded by a few degrees, we have two
    options to correct this situation:Overprotect the screw, giving it greater thickness of rock wool, or
    • Increase the diameter of the thyme, so that being the most favorable mass, the temperature reached in the 60th minute will be lower. In addition to increasing the diameter
    5 of the screw is increasing the safety coefficient applied in the previous expression of shear resistance.
    For the above, we will choose the second option, so we will adopt a screw with a diameter of 20 mm, obtaining the results referred to in table 24.
    L1eg, t 69a, t T a, t minute gas temperature 2 (
    'c' c 'C
    36.00 36.00 -3.093 32.907
    10 678.43 7.59 1,866 19,032 20 781.35 3.77 2,419 63,420 30 841.80 2.51 2,567 113,669 40 884.74 1.88 2,588 165,353 SO 918, OS 1, SO 2,551 216,185 60 945.34 1 , 25 2,484 267,138 70 968.39 1.07 2,401 315,969 80 988.37 0.94 2,309 363,036 90 1005.99 0.83 2,213 408,212
    Table 25
    15 As can be seen in Table 25, the screw temperature in the 60th minute of fire would be 267 ° C, which would be within the range of the material's service temperature. It may be surprising that the temperature of the polymer is higher than that of steel, but, as already said, this is due to the high specific heat of the PPS. By minute 60, the characteristics of the steel profile will be as indicated for case 1
    20 0-60-3-0, which is shown in table 26. In the 60th minute, with the passive protection conditions available to the structure, the elastic modulus of the steel has not yet begun to fall, so It can be considered to be guaranteed:
    • On the one hand, the 53% GLASS FIBER AND MINERAL PPS screw will fail once
    25 reached a temperature higher than the maximum service, that is, more than 290 ° C, after 60 minutes of fire.
    On the other hand, the screw would fail long before the deformations produced in the structure by the thermal load and the variation of the mechanical parameters of the steel are sufficient to compromise the sectorization with the adjacent ships.
    Thickness
    T '
    Available
    Profile
    Exposed
    protection
    Steel
    Cion
    Table 26
    Study of the Effect of Temperature on the Screw
    10 In this section we will study the possible dilations that may result in the increase in temperature of the material, both in the screw and in the profile of the structure to be joined. For this, the relevant data we need is the coefficient of thermal expansion of the PPS used to manufacture the screw. The program for this value (actually for all
    15 properties) reflects an interval, within which, and since the piece is made to order, we choose the value that suits us. In this case, the smallest value of the interval will be chosen, because what is of interest is that the coefficient of thermal expansion be as close as possible to that of steel. For the PPS, the coefficient of thermal expansion can range from: OPPS = 34.2: 144 I-ldeformation fOC.
    20 The possible expansion in the longitudinal direction of the screw axis, and in the radial direction thereof, must be studied.
    Elongation in the longitudinal direction of the screw shaft
    25 We will calculate the increase in PPS and Steel length (figure 35). For the temperature increase, a standard initial temperature of 25 ° C will be taken into account. Also remember that the thickness of the sheets justified in the previous section is 1.86mm.
    EC.40
    deformation
    ilL pps = 34 · 10-6 ° C. 2422 e. 0.00372 m = 0.000031 m EC.41
    Now we calculate the increase in steel length:
    EC.42
    deformation
    !: J.Lac = 1210-2C. 164º C. 0.00372 m = 0.0000073 m = O.0073mm EC.43
    As can be seen, the increase in screw length, in the longitudinal direction of its axis, is so small that it can be neglected for the purpose of a possible prestressing of the screw.
    Elongation perpendicular to the screw axis
    In this case, the expansion in the direction perpendicular to the axis of the screw will be studied (figure
    36).
    10 It must be taken into account that, on the one hand, the screw will increase in diameter, and on the other hand, the hole in the sheet will decrease in diameter, so the two length increments to be calculated will have to be subtracted.
    It is also necessary to take into account that the diameters of the screw holes,
    They are indicated in section 58.3 of Royal Decree 751/2011. of May 27. approving the Structural Steel Instruction (EAE), which states that: The standard diameter of the holes will be equal to that of the screw stem plus:
    1 mm for 12 and 14 mm diameter screws;
    1 or 2 mm for screws from 16 to 24 mm;
    2 or 3 mm for screws 27 mm or larger.
    So, in principle, for the screw diameter 20mm, a hole diameter of 21.5mm will be considered (figure 37). The increase in screw diameter will be:
    EC.44
    derormacion
    !: J.Lpps = 34'10-2C. 242º C '0.02 m = 0.00016 m = 0.16mm · EC.45
    The decrease in hole diameter will be:
    EC.46
    deformation
    !: J.L ac = 1210-6. 164º C. 0.0215 m = 0.000042 m = 0.042mm · EC.47
    'C
    As noted, the final screw diameter would be 20.16mm while the diameter of the
    hole for the 60 minute fire would be 21.46 mm, so it can be ruled out thatthere could be an increase in tensions in the boundary zones of the screw-plate joint, due to5 to a strangulation between them.
    Conclusion of the method of using screw as a thermomechanical fuse
    As seen above, it is understood that employment would be sufficiently justified
    10 of a screw of PPS material with a diameter of 20 mm, and features described in the previous sections, so that this connecting element served as a mechanical fuse to cause the structure to collapse at said junction points, causing the screw to fail, not by effort, but by high temperature of the same, causing the structure, once reached the maximum temperature (and always after 60 minutes of fire) fall from
    15 in a vertical way, thanks to the shape of the cut of the union and thus preventing efforts to be transmitted to the common pillars with the adjacent ships, which can compromise the sectorization with them.
    权利要求:
    Claims (19)
    [1]
    1. Procedure for controlling the collapse of structures of industrial establishments in case of fire characterized by comprising the following stages:
    one. Characterization of the industrial establishment whose collapse in case of fire is to be controlled, which includes the determination of the actions or loads that act on the structure of said establishment;
    [2]
    2. Design and calculation of the impairment to be practiced in the structure of said industrial establishment; and
    [3]
    3. Implementation of the selected weakening.
    [2]
    2. Method according to the preceding claim characterized in that the step of
    characterization includes the determination of the following actions or loads: Permanent loads (own weight of all the elements (structure, facades, roofs, anchors, doors, etc.); Snow overload (action on the roof that, in a horizontal terrain, it is determined by the altitude and the winter climate zone);
    • Wind action or load (action on roofs and walls):
    • Overload of use (takes into account the weight of people on the deck); Y
    • Seismic action or load, which depends directly on the mass of the building.
    [3]
    3. Method according to the preceding claim characterized in that the characterization of the wind action or load takes into account the following three wind directions:
    Wind + X, which corresponds to the direction parallel to the porches;
    • Wind + Y, perpendicular to the front facade; YWind -Y, like the wind + Y, but on the rear facade.
    [4]
    4. Method according to the preceding claim characterized in that it comprises the determination and evaluation of the wind for the + X direction considering either open or closed gaps, either pressure or suction in both skirts, and either pressure-suction or suction-pressure.
    [5]
    5. Method according to the preceding claim characterized in that the determination and evaluation of the wind for the + and Y-directions and considering either open gaps or 59
    closed.
    [6]
    Method according to claim 2, characterized in that the characterization of the load or seismic action comprises the determination of:
    • The acceleration of calculation,The periods and modes of vibration,
    • The response coefficient, which depends on the level of ductility;
    • The masses involved, andThe equivalent static forces.
    [7]
    7. Method according to any of the preceding claims characterized in that the design and calculation stage comprises both the calculation of the thermal load and the analysis of the behavior of the structure, analysis which in turn comprises:
    one. The selection of fire scenarios,
    [2]
    2. The determination of the corresponding fire action calculation fire ");
    [3]
    3. The calculation of the temperature evolution inside the structural elements as a result of its exposure to the "calculon fire adopted; and
    [4]
    Four. The calculation of the mechanical behavior of the structure exposed to said calculation fire over a specific time interval.
    [8]
    8. Method according to the preceding claim characterized in that the design and calculation stage takes into account, for the design of the weakening, the weakening method by reducing the section of the film, which consists in modifying (weakening) the structure in the less requested in terms of supported voltages, modifying their characteristics (for example, dimensions, geometry, mechanical values, etc.).
    [9]
    9. Method according to claim 7 characterized in that the design and calculation stage takes into account, for the design of the weakening, the use of screw as a thermomechanical fuse, which consists of placing a short piece (screw or similar) in less requested areas in as far as supported voltages are concerned, said piece cuts with the following characteristics:
    • Made of an isotropic material,
    • Elastic limit between 40 and 230 MPa,Maximum operating temperature between 180 and 290 ° C, Y
    Specific heat similar to the construction material of the parts of the structure that said thermomechanical fuse must join.
    [10]
    10. Method according to the preceding claim characterized in that the specific heat5 of the thermomechanical fuse manufacturing material is between 940 and 1300 J / kg K.
    [11 ]
    eleven . Method according to the preceding claim characterized in that the thermomechanical fuse manufacturing material is a polymer composed of glass fiber and mineral.
    [12]
    12. Method according to the preceding claim characterized in that the polymer composed of fiberglass and mineral of the thermomechanical fuse has an elastic limit of 139 MPa, a maximum operating temperature of 290 ° C, and a specific heat of 1200 J / kg K.
    [13]
    13. Method according to any of claims 9 to 12 characterized in that the connection by means of the thermomechanical fuse is carried out either by means of a flush-mounted connection
    by patella (articulated joint).
    '' '' '' '' '':; 0 '' -----, ----,
    f ~. &
    1 E •. II = tan o.
    Figure 1
    [0]
    0.500 1>< 0.500
    ,
    Figure 2
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    同族专利:
    公开号 | 公开日
    ES2664131A1|2018-04-18|
    ES2637466B2|2018-06-22|
    ES2664131B1|2019-01-22|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US1151289A|1914-09-21|1915-08-24|Felix Lawrence Saino|Fusible fastening.|
    US3708932A|1969-06-04|1973-01-09|Conder International Ltd|Ceiling system|
    US3716959A|1970-09-15|1973-02-20|J Bernardi|Beam end construction for semi-rigid connection to a column|
    US3974607A|1974-10-21|1976-08-17|United States Gypsum Company|Fire-rated common area separation wall structure having break-away clips|
    WO1999001624A1|1997-06-30|1999-01-14|Noel Christopher Manning|A fire-retardant roof construction|
    ES2341582T3|2007-06-19|2010-06-22|Arcelormittal Commercial Sections S.A.|WALL FURNITURE.|
    US20120279143A1|2011-05-02|2012-11-08|Fero Corporation|Break away firewall connection system and a method for construction|
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