A method for calculating load-displacement curves of steel structure modular building floor systems

Abstract

The present invention discloses a load-displacement curve calculation method for a steel structure modular building floor system, which belongs to the field of civil engineering and includes the following steps: S1. Calculating the yield bearing capacity based on the yield load theory; S2. Derivation of a hardening coefficient based on various parameters of the steel structure modular building, and then multiplying the yield bearing capacity by the hardening coefficient to obtain the ultimate bearing capacity; S3. Calculating the yield displacement and ultimate displacement based on the derived and fitted parameters; S4. Obtaining two points using the calculated yield bearing capacity and yield displacement, as well as the ultimate bearing capacity and ultimate displacement, and connecting the two obtained points into a bifold line to obtain a simplified displacement load curve graph. The present invention adopts the above-mentioned load-displacement curve calculation method for a steel structure modular building floor system, and the calculation process is simple, providing theoretical support for the calculation method of the yield bearing capacity, ultimate bearing capacity, yield displacement, and ultimate displacement when a column in the steel structure modular building floor system fails.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering, and in particular to a method for calculating a load-displacement curve of a steel structure module building floor system. Background Art

[0002] In recent years, steel structure modular buildings have been increasingly widely used in actual projects due to their advantages over other construction methods, such as high efficiency and energy saving, controllable quality, high adaptability, and excellent economy.

[0003] However, once a steel structure modular building encounters unexpected accidental loads, since horizontally adjacent modular units are only connected at the corners and the floor slabs of the modular units are only constrained at the four corners, its integrity is poorer than that of traditional frames and it is more prone to collapse. Therefore, research on the collapse performance of steel structure modular floor systems when the center column fails is urgent.

[0004] However, at present, there are not many studies by domestic and foreign scholars on the calculation method of load-displacement curve when columns fail in structural modular building floor systems, and there is an urgent need to conduct research on this. Summary of the Invention

[0005] The purpose of the present invention is to provide a load-displacement curve calculation method for a steel structure modular building floor system, which can provide theoretical support for the calculation method of the yield bearing capacity, ultimate bearing capacity, yield displacement and ultimate displacement when the column fails in the steel structure modular building floor system.

[0006] To achieve the above object, the present invention provides a method for calculating a load-displacement curve of a steel structure modular building floor system, comprising the following steps:

[0007] S1. Calculate the yield load capacity of the structure according to the yield load theory;

[0008] S2. The hardening coefficient is derived based on the span of the beam in the short span direction, the span of the beam in the long span direction, the beam section height, the plate thickness, and the steel bar parameters in the plate of the steel structure module building. , then multiply the yield bearing capacity by the hardening coefficient Obtain the ultimate bearing capacity of the structure;

[0009] S3. Calculate the yield displacement and ultimate displacement of the structure based on the parameters derived and fitted in steps S1 and S2;

[0010] S4. Two points are obtained by calculating the yield bearing capacity and yield displacement as well as the ultimate bearing capacity and ultimate displacement, and the two points are connected into a bifold line to obtain a simplified displacement load curve diagram of the steel structure modular building when the middle column fails.

[0011] Preferably, S1 specifically includes the following steps:

[0012] S11. Calculate the yield strength of steel bars per unit width of floor slabs;

[0013] S12. Calculate the yield bending moment per unit width of the floor slab based on the obtained yield tension of the reinforcement per unit width of the floor slab;

[0014] S13. Calculate the plastic section resistance moment of the beam;

[0015] S14. Calculate the negative yield bending moment of the longitudinal beam and the transverse beam and the positive yield bending moment of the longitudinal beam and the transverse beam based on the plastic section resistance moment of the beam;

[0016] S15. Calculate the yield bearing capacity based on the parameters obtained in S12 and S14.

[0017] Preferably, in S11, the calculation formula for the yield tensile force of the steel bars per unit width of the floor slab is:

[0018] ;

[0019] Where, T is the yield tension of the steel bars per unit width of the slab; is the yield strength of steel bars; r is the diameter of the steel bar; b is the unit width of the board; s is the spacing between steel bars;

[0020] In S12, the calculation formula for the yield moment per unit width of the plate is:

[0021] ;

[0022] Where, is the yield moment per unit width of the plate; is the effective height of the plate section; is the compressive strength of concrete;

[0023] In S13, the calculation formula for the plastic section resistance moment of the beam is:

[0024] ;

[0025] Where, is the plastic section resistance moment of the beam, D is the beam section height; is the thickness of the beam, is the flange width;

[0026] In S14, the calculation formula for the beam yield moment is:

[0027] ;

[0028] Where, is the negative yield moment of the long span beam; is the positive yield moment of the long span beam; is the negative yield moment of the short span beam; is the positive yield moment of the short span beam; is the yield strength of the steel beam;

[0029] In S15, the calculation formula for yield bearing capacity is:

[0030] ;

[0031] Where, Fy is the yield bearing capacity; L is the span of the beam in the long span direction after column failure, i.e., the x direction; is the span of the beam in the short span direction after column failure, i.e., the y direction.

[0032] Preferably, in S2, specifically:

[0033] Calculate the floor slab reinforcement ratio p :

[0034] ;

[0035] Where, T s is the plate thickness;

[0036] Calculate the span-to-thickness ratio of the plate along the short span STR :

[0037] ;

[0038] Calculate the span-to-height ratio of the beam along the short span SDR :

[0039] ;

[0040] Calculate the aspect ratio of the board :

[0041] ;

[0042] Hardening coefficient The calculation formula is:

[0043] ;

[0044] Calculate the ultimate bearing capacity of columns in steel modular building floor systems when they fail:

[0045] ;

[0046] Where,F u is the ultimate bearing capacity.

[0047] Preferably, in S3, the calculation formula for yield displacement is:

[0048] ;

[0049] Where, V y is the yield displacement.

[0050] Preferably, in S3, the calculation formula for the limit displacement is:

[0051] ;

[0052] Where, V u is the limit displacement.

[0053] Therefore, the present invention adopts the above-mentioned load-displacement curve calculation method for the steel structure modular building floor system. The calculation process is simple and clear, and provides theoretical support for the calculation method of the yield bearing capacity, ultimate bearing capacity, yield displacement and ultimate displacement when the column fails in the steel structure modular building floor system.

[0054] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 1 is a top view schematic diagram of a steel structure modular building floor system under failure of a center column in an embodiment of the present invention;

[0056] Figure 2 This is a 1 / 4 model diagram of the finite element model of the steel structure modular building floor system in an embodiment of the present invention;

[0057] Figure 3 1 is a structural diagram of a steel structure modular building floor system in an embodiment of the present invention;

[0058] Figure 4 Schematic diagram of the floor and steel bar spacing of the steel structure modular building floor system in an embodiment of the present invention;

[0059] Figure 5 This is a flow chart of a method for calculating a load-displacement curve of a steel structure modular building floor system according to the present invention;

[0060] Figure 6 1 is a two-fold load-displacement curve diagram of the steel structure modular building floor system obtained in an embodiment of the present invention.

[0061] Reference numerals

[0062] 1. Hinge boundary conditions; 2. Square hollow column; 3. C-beam; 4. Floor slab; 5. Rebar. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0064] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0065] Example 1

[0066] In this embodiment, a steel structure modular building of a student dormitory of a certain city university is taken as an example, and its top view is as follows: Figure 1 As shown in Figure 1, the floor system has a planar dimension of 12 meters long and 6 meters wide. The beams are made of Q235 steel with a yield strength of 235 MPa and a channel-shaped cross-section of 200 mm × 70 mm × 6 mm. The floor slab is 100 mm thick, the concrete compressive strength is 22.9 MPa, and the effective height of the floor slab is 80 mm. Based on the above data, the corresponding 1 / 4 model of the finite element model is shown in the figure below. Figure 2 As shown, the structural diagram of the student dormitory in this embodiment is as follows Figure 3 As shown in Figure 1. Among them, the spacing of steel bars in the slab is 180mm. Figure 4 As shown, the diameter of the steel bar is 10 mm and the yield strength of the steel bar is 300 MPa.

[0067] A load-displacement curve calculation method for a steel structure modular building floor system is used in this embodiment. Figure 5 As shown, the specific steps include:

[0068] S1. Calculate the yield load capacity of the structure based on the yield load theory, which specifically includes the following steps:

[0069] S11. Calculate the yield strength of steel bars per unit width of floor slab (N / mm):

[0070] ;

[0071] Where, T is the yield tension of the steel bars per unit width of the slab; is the yield strength of steel bars; r is the diameter of the steel bar (mm); b is the unit width of the board (mm); s is the steel bar spacing (mm).

[0072] S12. Calculate the yield bending moment per unit width of the floor slab (N∙mm / m) based on the yield tensile force of the steel bars per unit width of the floor slab:

[0073] ;

[0074] Where, is the yield moment per unit width of the floor slab; is the effective height of the floor section; is the compressive strength of concrete.

[0075] S13. Calculate the plastic section resistance moment of the beam (mm 3 ):

[0076] ;

[0077] Where, W P is the plastic section resistance moment of the beam, D is the beam section height (mm); is the thickness of the beam (mm), is the flange width (mm).

[0078] S14. Calculate the negative yield bending moment of the longitudinal beam and the positive yield bending moment of the longitudinal beam and the transverse beam based on the plastic section resistance moment of the beam (N∙mm):

[0079] ;

[0080] Where, is the negative yield moment of the long span beam; is the positive yield moment of the long span beam; is the negative yield moment of the short span beam; is the positive yield moment of the short span beam; is the yield strength of the steel beam.

[0081] S15. Calculate the yield bearing capacity (N) based on the parameters obtained in S12 and S14:

[0082] ;

[0083] Where, Fyis the yield bearing capacity; L is the span of the beam in the long span direction after column failure, i.e., the x direction (mm); is the span of the beam in the short span direction after column failure, i.e., the y direction (mm).

[0084] S2. The hardening coefficient is derived based on the span of the beam in the short span direction, the span of the beam in the long span direction, the beam section height, the plate thickness, and the steel bar parameters in the plate of the steel structure module building. , then multiply the yield bearing capacity by the hardening coefficient The ultimate bearing capacity of the structure is obtained as follows:

[0085] Calculate the floor slab reinforcement ratio p :

[0086] ;

[0087] Where, Ts is the plate thickness (mm).

[0088] Calculate the span-to-thickness ratio of the plate along the short span STR :

[0089] ;

[0090] Calculate the span-to-height ratio of the beam along the short span SDR :

[0091] ;

[0092] Calculate the aspect ratio of the board :

[0093] ;

[0094] Hardening coefficient The calculation formula is:

[0095] ;

[0096] Calculate the ultimate bearing capacity (N) of the steel modular building floor system when the columns fail:

[0097] ;

[0098] Where, F u is the ultimate bearing capacity.

[0099] S3. Calculate the yield displacement and ultimate displacement of the structure based on the parameters derived and fitted in steps S1 and S2.

[0100] The calculation formula for the yield displacement (mm) of the structure is:

[0101] ;

[0102] Where, V y is the yield displacement.

[0103] The calculation formula for the ultimate displacement (mm) of the structure is:

[0104] ;

[0105] Where, V u is the limit displacement.

[0106] S4. Yield bearing capacity obtained by calculation F y and yield displacement V y and ultimate bearing capacity F u and limit displacement V u Get two points and connect them into a double broken line to get the simplified displacement load curve of the steel structure module building when the middle column fails, as shown in Figure 6 shown.

[0107] Therefore, the present invention adopts the above-mentioned load-displacement curve calculation method for the steel structure modular building floor system. The calculation process is simple and clear, and provides theoretical support for the calculation method of the yield bearing capacity, ultimate bearing capacity, yield displacement and ultimate displacement when the column fails in the steel structure modular building floor system.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for calculating the load-displacement curve of a steel structure modular building floor system, characterized in that: The following steps are involved: S1. Calculate the yield load capacity of the structure according to the yield load theory; S2. The hardening coefficient is derived based on the span of the beam in the short span direction, the span of the beam in the long span direction, the beam section height, the plate thickness, and the steel bar parameters in the plate of the steel structure module building. , then multiply the yield bearing capacity by the hardening coefficient Obtain the ultimate bearing capacity of the structure; In S2, specifically: Calculate the floor slab reinforcement ratio : ； Where, is the plate thickness; is the diameter of the steel bar; is the spacing between steel bars; Calculate the span-to-thickness ratio of the plate along the short span : ； Calculate the span-to-height ratio of the beam along the short span : ； Where, is the beam section height; Calculate the aspect ratio of the board : ； Where L is the span of the beam in the long span direction after column failure, i.e., the x-direction; is the span of the beam in the short span direction after column failure, i.e., the y direction; Hardening coefficient The calculation formula is: ； Calculate the ultimate bearing capacity of columns in steel modular building floor systems when they fail: ； Where, is the ultimate bearing capacity; S3. Calculate the yield displacement and ultimate displacement of the structure based on the parameters derived and fitted in steps S1 and S2; The calculation formula for yield displacement is: ； Where, is the yield displacement; The calculation formula for the ultimate displacement is: ； Where, is the limit displacement; S4. Two points are obtained by calculating the yield bearing capacity and yield displacement as well as the ultimate bearing capacity and ultimate displacement, and the two points are connected into a bifold line to obtain a simplified displacement load curve diagram of the steel structure modular building when the middle column fails.

2. The method for calculating a load-displacement curve of a steel structure modular building floor system according to claim 1, wherein: S1 specifically includes the following steps: S11. Calculate the yield strength of steel bars per unit width of floor slabs; S12. Calculate the yield bending moment per unit width of the floor slab based on the obtained yield tension of the reinforcement per unit width of the floor slab; S13. Calculate the plastic section resistance moment of the beam; S14. Calculate the negative yield bending moment of the longitudinal beam and the transverse beam and the positive yield bending moment of the longitudinal beam and the transverse beam based on the plastic section resistance moment of the beam; S15. Calculate the yield bearing capacity based on the parameters obtained in S12 and S14.

3. The method for calculating a load-displacement curve of a steel structure modular building floor system according to claim 2, characterized in that: In S11, the calculation formula for the yield tension of the steel bars per unit width of the floor slab is: ； Where, is the yield tension of the steel bars per unit width of the slab; is the yield strength of steel bars; is the unit width of the board; In S12, the calculation formula for the yield moment per unit width of the floor slab is: ； Where, is the yield moment per unit width of the floor slab; is the effective height of the floor section; is the compressive strength of concrete; In S13, the calculation formula for the plastic section resistance moment of the beam is: ； Where, is the plastic section resistance moment of the beam; is the thickness of the beam, is the flange width; In S14, the calculation formula for the beam yield moment is: ； Where, is the negative yield moment of the long span beam; is the positive yield moment of the long span beam; is the negative yield moment of the short span beam; is the positive yield moment of the short span beam; is the yield strength of the steel beam; In S15, the calculation formula for yield bearing capacity is: ； Where, is the yield bearing capacity.

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