Load-displacement curve calculation method of steel structure module building floor system

Abstract

The invention discloses a load-displacement curve calculation method of a steel structure module building floor system, which belongs to the field of civil engineering and comprises the following steps: S1, calculating yield bearing capacity according to a yield load theory; s2, deriving a hardening coefficient according to various parameters of the steel structure module building, and multiplying the yield bearing capacity by the hardening coefficient to obtain ultimate bearing capacity; s3, calculating yield displacement and limit displacement according to the derived and fitted parameters; s4, two points are obtained through the yield bearing capacity and the yield displacement obtained through calculation and the ultimate bearing capacity and the ultimate displacement, the two obtained points are connected into a double-fold line, and a simplified displacement load curve graph is obtained. According to the load-displacement curve calculation method of the steel structure module building floor system, the calculation process is simple, and theoretical support is provided for the calculation method of the yield bearing capacity, the ultimate bearing capacity, the yield displacement and the ultimate displacement when the columns in the steel structure module building floor system fail.

Description

Technical Field

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

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

[0003] However, once a steel structure modular building encounters an unexpected accidental load, since the horizontally adjacent module units are only connected at the corners, and the floor slabs of the module units are only constrained at the four corners, its integrity is worse than that of a traditional frame and it is more likely to collapse. Therefore, it is urgent to study the collapse performance of the steel structure modular floor system when the middle column fails.

[0004] At present, there are not many studies by domestic and foreign scholars on the method for calculating the load-displacement curve when the middle column of the structural modular building floor system fails, and it is urgent to carry out research on this. Summary of the Invention

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

[0006] To achieve the above purpose, the present invention provides a method for calculating the load-displacement curve of a steel structure modular building floor system, including the following steps: S1. Calculate the yield bearing capacity of the structure according to the yield load theory; S2. Derive the hardening coefficient based on the span of the beam in the short-span direction, the span of the beam in the long-span direction, the height of the beam section, the thickness of the slab, and the steel bar parameters in the slab of the steel structure modular building, and then multiply the yield bearing capacity by the hardening coefficient to obtain the ultimate bearing capacity of the structure; to obtain the ultimate bearing capacity of the structure; S3. Calculate the yield displacement and ultimate displacement of the structure according to the parameters derived and fitted in steps S1 and S2; S4. Obtain two points through the calculated yield bearing capacity and yield displacement, and the ultimate bearing capacity and ultimate displacement, and connect the two obtained points into a double broken line to obtain a simplified displacement-load curve graph of the steel structure modular building when the middle column fails.

[0007] Preferably, in S1, it specifically includes the following steps: S11. Calculate the yield tension of the steel bars per unit width of the floor slab; S12. Calculate the yield moment per unit width of the floor slab based on the obtained yield tensile force of the steel bars per unit width of the floor slab. S13. Calculate the plastic section modulus of the beam. S14. Calculate the negative yield moment and the positive yield moment of the longitudinal beam and the cross beam based on the plastic section modulus of the beam. S15. Calculate the yield bearing capacity based on the parameters obtained in S12 and S14.

[0008] Preferably, in S11, the calculation formula for the yield tensile force of the steel bars per unit width of the floor slab is: ; In the formula, T is the yield tensile force of the steel bars per unit width of the floor slab; is the yield strength of the steel bars; r is the diameter of the steel bars; b is the unit width of the slab; s is the spacing of the steel bars; In S12, the calculation formula for the yield moment per unit width of the slab is: ; In the formula, is the yield moment per unit width of the slab; is the effective height of the slab section; is the compressive strength of the concrete; In S13, the calculation formula for the plastic section modulus of the beam is: ; In the formula, is the plastic section modulus of the beam, D is the height of the beam section; is the thickness of the beam, is the flange width; In S14, the calculation formula for the yield moment of the beam is: ; In the formula, 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 the yield bearing capacity is: ; In the formula, Fy is the yield bearing capacity; L is the span of the beam in the long-span direction, i.e., the x-direction, after the column fails; It is the span of the beam in the short-span direction, i.e., the y-direction, after the column fails.

[0009] Preferably, in S2, specifically: Calculate the reinforcement ratio of the floor slab p : ; In the formula, T s is the slab thickness; Calculate the span-depth ratio of the slab along the short span STR : ; Calculate the span-depth ratio of the beam along the short span SDR : ; Calculate the aspect ratio of the slab : ; The calculation formula of the hardening coefficient is: ; Calculate the ultimate bearing capacity when the column fails in the steel structure module building floor system: ; In the formula, F u is the ultimate bearing capacity.

[0010] Preferably, in S3, the calculation formula of the yield displacement is: ; In the formula, V y is the yield displacement.

[0011] Preferably, in S3, the calculation formula of the ultimate displacement is: ; In the formula, V u is the ultimate displacement.

[0012] Therefore, the present invention adopts the above-mentioned method for calculating the load-displacement curve of a steel structure module building floor system, and the calculation process is simple and clear, providing a theoretical support for the calculation methods of the yield bearing capacity, ultimate bearing capacity, yield displacement and ultimate displacement when the column fails in the steel structure module building floor system.

[0013] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. Description of the Drawings

[0014] Figure 1 It is a top view schematic diagram of the steel structure modular building floor system in the embodiment of the present invention under the failure of the middle column; Figure 2 It is a 1 / 4 model diagram of the finite element model of the steel structure modular building floor system in the embodiment of the present invention; Figure 3 It is a structural schematic diagram of the steel structure modular building floor system in the embodiment of the present invention; Figure 4 It is a schematic diagram of the floor slab and the steel bar spacing of the steel structure modular building floor system in the embodiment of the present invention; Figure 5 It is a flow chart of the load-displacement curve calculation method of a steel structure modular building floor system of the present invention; Figure 6 It is a two-line load-displacement curve graph of the steel structure modular building floor system obtained in the embodiment of the present invention.

[0015] Reference numerals 1. Hinged boundary condition; 2. Square hollow column; 3. C-shaped beam; 4. Floor slab; 5. Steel bar. Detailed implementation manners

[0016] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0017] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before the term cover the elements or objects listed after the term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0018] Embodiment 1 In this embodiment, taking the steel structure modular building of the student dormitory of a certain university as an example, its top view is as Figure 1As shown, the floor system has a plan dimension of 12 meters in length and 6 meters in width. The beam is made of Q235 steel with a yield strength of 235 MPa, and its cross-section is channel-shaped with a size of 200 mm × 70 mm × 6 mm; the floor slab thickness is 100 mm, the concrete compressive strength is 22.9 MPa, and the effective height of the floor slab is 80 mm. Based on the above data, a 1 / 4 model diagram of the corresponding finite element model is as shown in Figure 2 As shown, the structural schematic diagram of the student dormitory in this embodiment is as shown in Figure 3 As shown. Among them, the spacing of the steel bars in the slab is 180 mm, as shown in Figure 4 As shown, the diameter of the steel bar is 10 mm, and the yield strength of the steel bar is 300 MPa.

[0019] A method for calculating the load-displacement curve of a steel structure modular building floor system used in this embodiment is as shown in Figure 5 As shown, it specifically includes the following steps: S1. According to the yield load theory, calculate the yield bearing capacity of the structure, which specifically includes the following steps: S11. Calculate the yield tension of the steel bars per unit width of the floor slab (N / mm): ;

[0020] In the formula, T is the yield tension of the steel bars per unit width of the floor slab; is the yield strength of the steel bar; r is the diameter of the steel bar (mm); b is the unit width of the slab (mm); s is the spacing of the steel bars (mm).

[0021] S12. Calculate the yield moment per unit width of the floor slab (N∙mm / m) based on the obtained yield tension of the steel bars per unit width of the floor slab: ;

[0022] In the formula, is the yield moment per unit width of the floor slab; is the effective height of the floor slab cross-section; is the concrete compressive strength.

[0023] S13. Calculate the plastic section modulus of the beam (mm 3 ): ;

[0024] In the formula, W P is the plastic section modulus of the beam, D is the height of the beam cross-section (mm); is the thickness of the beam (mm), is the flange width (mm).

[0025] S14. Calculate the negative yield moment and positive yield moment of the longitudinal beam and cross beam according to the plastic section modulus of the beam (N∙mm): ;

[0026] In the formula, 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.

[0027] S15. Calculate the yield bearing capacity (N) according to the parameters obtained in S12 and S14: ;

[0028] In the formula, Fy is the yield bearing capacity; L is the span of the beam in the long-span direction, i.e., the x direction, after the column fails (mm); is the span of the beam in the short-span direction, i.e., the y direction, after the column fails (mm).

[0029] S2. Derive the hardening coefficient according to 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 modular building , and then multiply the yield bearing capacity by the hardening coefficient to obtain the ultimate bearing capacity of the structure, specifically: Calculate the reinforcement ratio of the floor slab p : ;

[0030] In the formula, Ts is the plate thickness (mm).

[0031] Calculate the span-thickness ratio of the plate along the short span STR : ;

[0032] Calculate the span-depth ratio of the beam along the short span SDR : ;

[0033] Calculate the aspect ratio of the plate : ;

[0034] The calculation formula of the hardening coefficient is: ;

[0035] Calculate the ultimate bearing capacity (N) when the column fails in the steel structure modular building floor system: ;

[0036] In the formula, F u is the ultimate bearing capacity.

[0037] S3. Calculate the yield displacement and ultimate displacement of the structure according to the parameters deduced and fitted in steps S1 and S2.

[0038] The calculation formula for the yield displacement (mm) of the structure is: ;

[0039] In the formula, V y is the yield displacement.

[0040] The calculation formula for the ultimate displacement (mm) of the structure is: ;

[0041] In the formula, V u is the ultimate displacement.

[0042] S4. Obtain two points through the calculated yield bearing capacity F y and yield displacement V y as well as the ultimate bearing capacity F u and ultimate displacement V u Connect the two obtained points into a double broken line to obtain a simplified displacement-load curve diagram of the steel structure modular building when the middle column fails, as shown in Figure 6 shown.

[0043] Therefore, the present invention adopts the above-mentioned method for calculating the load-displacement curve of a steel structure modular building floor system, and the calculation process is simple and clear, providing a theoretical support for the calculation methods of the yield bearing capacity, ultimate bearing capacity, yield displacement and ultimate displacement of the steel structure modular building floor system when the middle column fails.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions 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, It includes the following steps: S1. Calculate the yield bearing capacity of the structure according to the yield load theory; S2. Derive the hardening coefficient based on the span of the beam in the short-span direction, the span of the beam in the long-span direction, the height of the beam section, the thickness of the slab, and the reinforcement parameters in the slab, and then multiply the yield bearing capacity by the hardening coefficient to obtain the ultimate bearing capacity of the structure; ​ S3. Calculate the yield displacement and ultimate displacement of the structure according to the parameters derived and fitted in steps S1 and S2; S4. Obtain two points from the calculated yield bearing capacity, yield displacement, ultimate bearing capacity and ultimate displacement, and connect the two obtained points into a double broken line to obtain a simplified displacement-load curve diagram of the steel structure modular building when the middle column fails.

2. The load-displacement curve calculation method of a steel structure modular building floor system according to claim 1, characterized in that: In S1, it specifically includes the following steps: S11. Calculate the yield tension of the steel bars per unit width of the floor slab; S12. Calculate the yield moment per unit width of the floor slab according to the obtained yield tension of the steel bars per unit width of the floor slab; S13. Calculate the plastic section modulus of the beam; S14. Calculate the negative yield moment and positive yield moment of the longitudinal beam and cross beam according to the plastic section modulus of the beam; S15. Calculate the yield bearing capacity according to the parameters obtained in S12 and S14.

3. The load-displacement curve calculation method 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: ； Wherein, T is the yield tension of the steel bars per unit width of the floor slab; is the yield strength of the steel bars; r is the diameter of the steel bars; b is the unit width of the slab; s is the spacing of the steel bars; In S12, the calculation formula for the yield moment per unit width of the floor slab is: ； In the formula, is the yield moment per unit width of the floor slab; is the effective height of the floor slab section; is the concrete compressive strength; In S13, the calculation formula for the plastic section modulus of the beam is: ； In the formula, is the plastic section modulus of the beam, D is the height of the beam section; is the thickness of the beam, is the flange width; In S14, the calculation formula for the yield moment of the beam is: ； Wherein, 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 the yield bearing capacity is: ； In the formula, Fy is the yield bearing capacity; L is the span of the beam in the long-span direction, i.e., the x-direction, after the column fails; is the span of the beam in the short-span direction, i.e., the y-direction, after the column fails.

4. The load-displacement curve calculation method of a steel structure modular building floor system according to claim 3, characterized in that: In S2, specifically: Calculate the floor slab reinforcement ratio p : ； In the formula, T s is the plate thickness; Calculate the span-thickness ratio of the slab along the short span STR : ； Calculate the span-depth ratio of the beam along the short span SDR : ； Calculate the aspect ratio of the plate : ； Hardening coefficient The calculation formula is as follows: ； Calculate the ultimate bearing capacity when the middle column of the floor slab system of the steel structure modular building fails: ； In the formula, F u is the ultimate bearing capacity.

5. The load-displacement curve calculation method of a steel structure modular building floor system according to claim 4, characterized in that: In S3, the calculation formula for the yield displacement is: ； In the formula, V y is the yield displacement.

6. The load-displacement curve calculation method of a steel structure modular building floor system according to claim 4, characterized in that: In S3, the calculation formula for the ultimate displacement is: ； In the formula, V u is the limit displacement.

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