Method and system for calculating deflection of truss-web type steel-concrete composite beam

Abstract

The invention relates to the technical field of engineering design, in particular to a truss-web type steel-concrete composite beam deflection calculation method and system.The method comprises the steps that a mechanical simplified model of a truss-web type steel-concrete composite beam is built, calculation assumption is determined, and a calculation scheme is obtained; determining the acting mode of the external load on the composite beam; basic calculation parameters of the combined beam mechanical simplified model are determined; according to the action mode, calculating a rigidity reduction coefficient of the simply supported beam caused by shear deformation of a truss web member, a slippage effect of a steel-concrete connection interface and local deformation of a node under the action of different loads; calculating the equivalent flexural rigidity of the truss-web type composite beam; and calculating the deflection of the truss-web type steel-concrete composite beam under the action of different loads. By means of the method, the problem that an existing calculation method is poor in pertinence and applicability is effectively solved, so that the stress condition of the truss web type steel-concrete composite beam structure is correctly reflected; according to the method, multiple influences caused by discontinuity of the truss web members, including shear deformation of the truss web members, a slippage effect of a steel-concrete connection interface and additional deflection caused by local deformation of the nodes, are considered, and the midspan deflection of the truss-web type steel-concrete combined simply supported beam can be conveniently evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of engineering design, and in particular to a method and system for calculating the deflection of a truss-web steel-concrete composite beam. Background Art

[0002] The truss-web steel-concrete composite beam has broad application prospects in the field of long-span bridges due to its advantages such as light weight, convenient construction, and beautiful appearance. At present, the research and application of truss-web steel-concrete composite beam bridges in my country is still in its infancy. Due to the discontinuity of the truss web in structure, the existing design theories and methods cannot be directly used, and the promotion and application is relatively slow.

[0003] Several typical bridges that have been built have adopted finite element simulation models or converted non-continuous truss webs into closed box girders by equivalently treating them as continuous plate thicknesses. This calculation method is quite different from the actual stress state of the structure, and this analysis method is not very targeted and applicable.

[0004] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present disclosure, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0005] The present invention provides a method and system for calculating the deflection of a truss-web steel-concrete composite beam, thereby effectively solving the problems pointed out in the background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for calculating the deflection of a truss-web steel-concrete composite beam, the method comprising:

[0008] Construct a simplified mechanical model of the truss-web steel-concrete composite beam, determine the calculation assumptions, and obtain the calculation scheme;

[0009] Determine the action mode of external load on the truss-web steel-concrete composite beam;

[0010] Determine the basic calculation parameters of the simplified mechanics model of the simply supported beam according to the calculation assumption scheme and the load action mode;

[0011] According to the described action mode, the stiffness reduction coefficient of the simply supported beam caused by the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node under different loads is calculated respectively;

[0012] Calculate the equivalent bending stiffness of the truss-web composite beam according to the basic calculation parameters and the stiffness reduction coefficients under different loads;

[0013] According to the equivalent bending stiffness and basic calculation parameters, the deflection of the truss-web steel-concrete composite beam under different loads is calculated.

[0014] Furthermore, a simplified mechanical model of the truss-web steel-concrete composite beam is constructed, and the calculation assumptions are determined to obtain a calculation scheme, including:

[0015] According to the structural characteristics of the truss-web steel-concrete composite beam, a beam model is used for simplified modeling;

[0016] Determine calculation assumptions based on simplified modeling, including structural assumptions, material assumptions and load assumptions;

[0017] According to the determined calculation assumptions, the calculation method and steps are determined to obtain the calculation scheme. Furthermore, the external load action mode includes: mid-span concentrated load, 1 / 4 span two-point symmetrical load, and full span uniform load.

[0018] Furthermore, the deflection of the beam model caused by bending deformation under different loads includes the following formulas:

[0019]

[0020] in, They are the deflections of the hollow beam caused by bending deformation under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span, respectively. P is the concentrated load, q is the concentration of the uniformly distributed load, and L is the calculated span of the simply supported beam.

[0021] Furthermore, the stiffness reduction factor caused by the shear deformation of the truss web under different loads includes the following formulas:

[0022]

[0023] in, are the stiffness reduction factors caused by shear deformation of the truss web under the concentrated load at the mid-span, the symmetrical load at two points at 1 / 4 span, and the uniform load at the full span; α = E c / E s is the ratio of the elastic modulus of the concrete top and bottom plates to the elastic modulus of the truss web; L is the calculated span of the simply supported beam, I 0 is the bending inertia moment of the truss-web steel-concrete composite beam section, N is the number of half-span nodes, N' is the number of truss web members from the calculation section to the support, A s is the cross-sectional area of ​​the truss web, h s is the height of the truss web member, and θ is the inclination angle of the truss web member.

[0024] Furthermore, the stiffness reduction factor caused by the slip effect at the steel-concrete connection interface is calculated, and the formula includes:

[0025]

[0026] in, are the stiffness reduction coefficients caused by the sliding effect under the concentrated load at the mid-span, the symmetrical load at two points in the 1 / 4 span, and the uniformly distributed load at the full span, η is the coefficient related to the geometric parameters, and b is the distance from the loading point to the support.

[0027] Furthermore, the stiffness reduction coefficient formula caused by local deformation of the node is calculated, including:

[0028]

[0029] in, are the stiffness reduction factors under the concentrated load at mid-span, the symmetrical load at two points on the quarter span and the uniform load on the full span, s d is the internode distance, E c is the elastic modulus of the material, I j is the section inertia of the concrete slab within the transverse width of the single-node flange plate.

[0030] Furthermore, the equivalent bending stiffness of the composite beam is calculated as follows:

[0031]

[0032] in They are the equivalent bending stiffness of the composite beam under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span.

[0033] Furthermore, the mid-span deflection of the simply supported beam under the action of mid-span concentrated load, 1 / 4 span two-point symmetrical load, and full span uniformly distributed load are:

[0034]

[0035] in, and They are the mid-span deflection of a simply supported beam under concentrated load at the mid-span, symmetrical loading at two points on a quarter span, and uniformly distributed load on the full span.

[0036] A deflection calculation system for a truss-web steel-concrete composite beam, the system comprising:

[0037] The calculation scheme acquisition module constructs a simplified mechanical model of the truss-web steel-concrete composite beam, determines the calculation assumptions, and obtains the calculation scheme;

[0038] A load mode determination module is used to determine the action mode of the external load on the truss-web steel-concrete composite beam;

[0039] A basic parameter determination module, which determines the basic calculation parameters of the simplified mechanical model according to the calculation assumption scheme and the load action mode;

[0040] The reduction coefficient calculation module calculates the stiffness reduction coefficient of the simply supported beam under different loads due to the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node according to the action mode;

[0041] An equivalent stiffness calculation module calculates the equivalent bending stiffness of the truss-web composite beam according to the basic calculation parameters and the stiffness reduction coefficient under different loads;

[0042] The composite beam deflection calculation module calculates the deflection of the truss-web steel-concrete composite beam under different loads according to the equivalent bending stiffness and basic calculation parameters.

[0043] The technical solution of the present invention can achieve the following technical effects:

[0044] It effectively solves the problem that the existing calculation method cannot correctly reflect the structural stress conditions and has poor pertinence and applicability. It takes into account the multiple influences brought about by the discontinuity of the truss web, including the steel-concrete slip effect and the additional deflection caused by the local deformation of the node, and can easily evaluate the deflection in the mid-span of the truss-web steel-concrete composite simply supported beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 The figure is a flow chart of a method for calculating the deflection of a truss-web steel-concrete composite beam. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0049] Embodiment 1

[0050] like Figure 1As shown, the present invention provides a method for calculating the deflection of a truss-web steel-concrete composite beam, the method comprising:

[0051] S1: Construct a simplified mechanical model of the truss-web steel-concrete composite beam, determine the calculation assumptions, and obtain the calculation scheme;

[0052] S2: Determine the mode of action of external loads on truss-web steel-concrete composite beams;

[0053] Specifically, first, analyze the structural characteristics of the truss-web steel-concrete composite beam, including the span, support form, and cross-sectional shape of the beam. These factors will affect the way the external load is transmitted on the beam. Then, according to the actual use conditions and design requirements, determine the type of external load, including concentrated load, distributed load, etc.; determine the location of the external load, that is, the specific location where the load is applied to the beam, which may be in the middle of the span, symmetrical at two points in the span, or evenly distributed over the entire span; analyze the support conditions of the truss-web steel-concrete composite beam, including different types of supports such as simply supported, fixed, or cantilever. The type of support will affect the reaction of the external load on the beam. Consider the situations that the beam may encounter in actual use, such as temperature changes, wind loads, seismic loads, etc. These factors will also affect the way the external load acts. Taking the above factors into consideration, the way the external load acts on the truss-web steel-concrete composite beam can be determined, providing accurate boundary conditions and load conditions for subsequent deflection calculations.

[0054] S3: Determine the basic calculation parameters of the simplified mechanical model according to the calculation assumptions and load action mode;

[0055] Specifically, these parameters are usually modeled and calculated through structural design software, or determined according to relevant building codes and material standards.

[0056] S4: According to the action mode, calculate the stiffness reduction factor of the simply supported beam under different loads due to the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node;

[0057] Specifically, the purpose of calculating the stiffness reduction coefficient caused by the shear deformation of the truss web is to comprehensively consider the deformation influence of the structure when it is subjected to external loads, and to ensure the accuracy of the deflection calculation. The shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node are one of the important factors affecting the deflection of the truss-web steel-concrete composite beam, which has a significant impact on the overall stiffness of the beam. By calculating the stiffness reduction coefficient caused by the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node, the stiffness change of the structure under different loads can be more accurately evaluated, thereby providing a more reliable basis for the deflection calculation.

[0058] S5: Calculate the equivalent bending stiffness of the truss-web composite beam based on the basic calculation parameters and the stiffness reduction factor under different loads;

[0059] Specifically, the calculation of the equivalent stiffness of the truss-web composite beam is to comprehensively consider the various stiffness reduction effects of the structure under different loads and express it as an overall stiffness parameter. In actual engineering, when the structure is subjected to external loads, various forms of deformation will occur, including bending deformation, shear deformation, sliding deformation, etc., which will cause the stiffness of the structure to change. As a complex structural form, the stiffness change of the truss-web composite beam may be affected by many factors, such as the shear deformation of the truss web and the local deformation of the node. Therefore, by calculating the equivalent bending stiffness of the truss-web composite beam, these different stiffness reduction effects can be combined to obtain a comprehensive stiffness parameter for subsequent structural analysis and design. The equivalent stiffness can be regarded as the overall stiffness performance of the structure when subjected to external loads, which can more accurately reflect the actual working state of the structure.

[0060] S6: Based on the equivalent stiffness and basic calculation parameters, calculate the deflection of the truss-web steel-concrete composite beam under different loads.

[0061] The present invention effectively solves the problem that the existing calculation method cannot correctly reflect the stress conditions of the structure and has poor pertinence and applicability. It takes into account the multiple influences brought about by the discontinuity of the truss web, including the additional deflection caused by the steel-concrete slip effect and the local deformation of the node, and can conveniently evaluate the deflection in the mid-span of a truss-web steel-concrete composite simply supported beam.

[0062] As a preferred embodiment of the above embodiment, a simplified mechanical model of a truss-web steel-concrete composite beam is constructed, and calculation assumptions are determined to obtain a calculation scheme, including:

[0063] S11: According to the structural characteristics of the truss-web steel-concrete composite beam, the beam model is used for simplified modeling;

[0064] S12: Determine the calculation assumptions based on the simplified modeling situation, including structural assumptions, material assumptions and load assumptions;

[0065] S13: According to the determined calculation assumptions, determine the calculation method and steps to obtain the calculation plan.

[0066] Specifically, in this step, the structural characteristics of the truss-web composite beam should be considered first, such as the overall shape of the beam, the cross-sectional shape, and the connection method between the truss web and the concrete slab. Then, based on these characteristics, the truss-web composite beam is simplified into a beam model, which usually involves dividing the beam into several nodes and units, considering rotation and displacement at the nodes, and considering the internal force distribution inside the unit. The calculation assumptions are determined for the simplified modeling situation. The structural assumptions include considering the support conditions of the beam (simply supported, fixedly supported, etc.), constraints (free ends, fixed ends, etc.), geometric shapes (length of the beam, cross-sectional shape, etc.), etc. The material assumptions include assumptions on the properties of various materials in the composite beam (elastic modulus, bending strength, etc.), and the load assumptions include assumptions on the action of external loads (concentrated loads, uniformly distributed loads, etc.), load distribution, load combination, etc. According to the determined simplified model and calculation assumptions, appropriate calculation methods and steps are selected, which involves knowledge and methods in finite element analysis, elastic theory, structural mechanics, etc., to ensure that the calculation scheme can fully consider the stress conditions and deformation characteristics of the structure to accurately evaluate the performance of the truss-web steel-concrete composite beam.

[0067] As a preferred embodiment of the above embodiment, the external load action modes include: concentrated load in the middle of the span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span.

[0068] Specifically, mid-span concentrated load refers to applying a concentrated load at the mid-span position of the truss-web steel-concrete composite beam; 1 / 4 span two-point symmetrical loading refers to evenly applying the load at two points at 1 / 4 span of the truss-web steel-concrete composite beam, and symmetrically to the center line of the beam; full-span uniformly distributed load refers to evenly distributing the load over the entire span of the truss-web steel-concrete composite beam.

[0069] As a preferred embodiment of the above, the deflection of the beam model caused by bending deformation under different loads is calculated by the formula:

[0070]

[0071] in, They are the deflections of the hollow beam caused by bending deformation under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span, respectively. P is the concentrated load, q is the concentration of the uniformly distributed load, and L is the calculated span of the simply supported beam.

[0072] As a preferred embodiment of the above, the stiffness reduction coefficient caused by the shear deformation of the truss web under different loads is as follows:

[0073]

[0074] in, are the stiffness reduction factors caused by shear deformation of the truss web under the concentrated load at the mid-span, the symmetrical load at two points at 1 / 4 span, and the uniform load at the full span; α = E c / E s is the ratio of the elastic modulus of the concrete top and bottom plates to the elastic modulus of the truss web; L is the calculated span of the simply supported beam, I 0 is the bending inertia moment of the truss-web steel-concrete composite beam section, N is the number of half-span nodes, N' is the number of truss web members from the calculation section to the support, A s is the cross-sectional area of ​​the truss web, h s is the height of the truss web member, and θ is the inclination angle of the truss web member.

[0075] Specifically, the calculation of these formulas aims to evaluate the effect of shear deformation of truss webs on the overall stiffness of truss-web steel-concrete composite beams. First, the shear deformation of the truss webs will lead to a reduction in the stiffness of the beam, so it is necessary to calculate the corresponding stiffness reduction factors, which are determined by considering the deformation of the truss webs under different loads and combining them with the cross-sectional characteristics and material properties of the beam. The calculation of these coefficients takes into account multiple factors, including the geometry of the truss webs, the elastic modulus of the material, the type and size of the external loads, etc. Through these coefficients, the overall stiffness of the truss-web steel-concrete composite beams under different loads can be more accurately evaluated.

[0076] As a preferred embodiment of the above, the stiffness reduction coefficient caused by the sliding deformation is calculated, and the formula also includes:

[0077]

[0078] in, and are the stiffness reduction coefficients caused by sliding deformation under concentrated load at mid-span, symmetrical loading at two points in 1 / 4 span and uniformly distributed load at full span, η is a coefficient related to geometric parameters, and b is the distance from the loading point to the support.

[0079] Specifically, Among them, H is the height of the box beam, E s is the elastic modulus of the truss web. The purpose of designing this formula is to calculate a comprehensive coefficient η by considering the structural characteristics and material properties of the truss web steel-concrete composite beam, as well as the external load action mode. This coefficient covers the elastic modulus, cross-sectional performance, structural geometric parameters and load action mode of the concrete beam. Therefore, the influence of various factors on the stiffness reduction caused by local deformation of the node can be comprehensively considered. The numerator considers the influence of the strength of the concrete beam section and the load action mode on the local deformation of the node, and the denominator considers the influence of the geometric shape of the beam and the material properties of the truss web on the local deformation of the node. Combining these two aspects can more accurately describe the stiffness reduction coefficient caused by local deformation of the node.

[0080] For mid-span concentrated load, The calculation of depends on the geometry of the structure and the location of the external load application point. shows the influence of the structural geometry; for 1 / 4 span two-point symmetrical loading, The calculation of is related to the distance b from the loading point to the support, and also takes into account the influence of the geometric shape of the structure and the load position. Describes the relationship between the loading point location and the support distance, as well as the influence of the structural geometry; for full-span uniformly distributed load, The calculation of is related to the span length L, and also takes into account the influence of the geometric shape of the structure and the load position. Similar to the calculation in the case of concentrated load at mid-span, the effect of span length on stiffness is taken into account.

[0081] As a preferred embodiment of the above, the formula for calculating the stiffness reduction coefficient caused by the local deformation of the node includes:

[0082]

[0083] in, and are the stiffness reduction factors under the concentrated load at mid-span, the symmetrical load at two points on the quarter span, and the uniform load on the full span, respectively. d is the internode distance, E c is the elastic modulus of the material, I j is the section inertia of the concrete slab within the transverse width of the single-node flange plate.

[0084] Specifically, these ratios are used in the formula to calculate the stiffness reduction factor caused by local deformation of the node. d It represents the node spacing, that is, the distance between nodes, E c Represents the elastic modulus of concrete, which is a parameter describing the mechanical properties of concrete materials. j is a concrete slab section inertia moment about the node, describing the contribution of the geometric shape of the concrete section to its rotational inertia. The ratio of these parameters reflects the relationship between the stiffness characteristics of the concrete material and the distance between the nodes and the shape of the concrete section. By considering these ratios, we can better understand the impact of local deformation of the node on the overall stiffness. Therefore, the calculation of these ratios can provide a quantitative method to evaluate the impact of local deformation of the node on the overall structural stiffness.

[0085]

[0086] As a preferred embodiment of the above, the equivalent stiffness of the composite beam is calculated as follows:

[0087]

[0088] in, and They are the equivalent stiffness of the composite beam under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span.

[0089] Specifically, these formulas are used to calculate the equivalent stiffness of truss-web steel-concrete composite beams under different loads. Equivalent stiffness is a comprehensive index that reflects the overall stiffness characteristics of the structure under load. In these formulas, and They represent the equivalent stiffness of the composite beam under the concentrated load at the mid-span, the symmetrical load at two points at the quarter span, and the uniform load at the full span. The denominator includes several adjustment items for influencing factors, such as the stiffness reduction factor λ caused by the shear deformation of the truss web, the slip deformation of the steel-concrete connection interface, and the local deformation of the node. V , S and γ N ,These adjustment items comprehensively consider the deformation of the structure under different loads, so that the equivalent stiffness can more accurately reflect the overall stiffness characteristics of the structure.

[0090] As a preferred embodiment of the above, the mid-span deflections of the simply supported beam under the mid-span concentrated load, the 1 / 4 span two-point symmetrical loading, and the full span uniformly distributed load are respectively:

[0091]

[0092] in, and They are the mid-span deflection of a simply supported beam under the action of concentrated load at the mid-span, symmetrical loading at two points on a quarter span, and uniformly distributed load on the full span, respectively. P is the concentrated load and q is the concentration of the uniformly distributed load.

[0093] Specifically, the calculation of deflection is usually to evaluate the degree of deformation of a structure under stress. The methods used in these formulas are based on the theories and assumptions of structural mechanics. Through simplified modeling of the structure and appropriate assumptions, the deflection of the structure under a specific load is calculated. In these formulas, the calculation of deflection involves the stiffness and stress conditions of the structure. The equivalent stiffness part reflects the overall stiffness characteristics of the structure under stress, while the load size affects the size of the deflection.

[0094] Embodiment 2

[0095] Based on the same inventive concept as the method for calculating the deflection of a truss-web steel-concrete composite beam in the aforementioned embodiment, the present invention further provides a system for calculating the deflection of a truss-web steel-concrete composite beam, the system comprising:

[0096] The calculation scheme acquisition module constructs a simplified mechanical model of the truss-web steel-concrete composite beam, determines the calculation assumptions, and obtains the calculation scheme;

[0097] Load mode determination module, which determines the action mode of external load on truss-web steel-concrete composite beams;

[0098] Basic parameter determination module, which determines the basic calculation parameters of the simplified mechanical model according to the calculation assumptions and load action mode;

[0099] The reduction coefficient calculation module calculates the stiffness reduction coefficient caused by the shear deformation of the truss web, the sliding deformation of the steel-concrete connection interface, and the local deformation of the node of the simply supported beam under different loads according to the action mode;

[0100] The equivalent stiffness calculation module calculates the equivalent bending stiffness of the truss-web composite beam based on the basic calculation parameters and the stiffness reduction coefficient under different loads;

[0101] The composite beam deflection calculation module calculates the deflection of truss-web steel-concrete composite beams under different loads based on the equivalent bending stiffness and basic calculation parameters.

[0102] The above-mentioned truss-web steel-concrete composite beam deflection calculation system in the present invention can effectively implement the truss-web steel-concrete composite beam deflection calculation method, and the technical effects that can be achieved are as described in the above-mentioned embodiments, which will not be repeated here.

[0103] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present application as defined therein, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, a person skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application and its equivalents, the present application is intended to include these modifications and variations.

Claims

1. A method for calculating the deflection of a truss-web steel-concrete composite beam, characterized in that: include: Construct a simplified mechanical model of the truss-web steel-concrete composite beam, determine the calculation assumptions, and obtain the calculation scheme; Determine the action mode of external load on the truss-web steel-concrete composite beam; Determine the basic calculation parameters of the simplified mechanical model according to the calculation assumption scheme and load action mode; According to the described action mode, the stiffness reduction coefficient of the simply supported beam caused by the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node under different loads is calculated; Calculate the equivalent bending stiffness of the truss-web composite beam according to the basic calculation parameters and the stiffness reduction coefficients under different loads; According to the equivalent bending stiffness and basic calculation parameters, the deflection of the truss-web steel-concrete composite beam under different loads is calculated.

2. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: A simplified mechanical model of the truss-web steel-concrete composite beam is constructed, and the calculation assumptions are determined to obtain the calculation scheme, including: According to the structural characteristics of the truss-web steel-concrete composite beam, a beam model is used for simplified modeling; Determine calculation assumptions based on simplified modeling, including structural assumptions, material assumptions and load assumptions; Based on the determined calculation assumptions, the calculation method and steps are determined to obtain the calculation scheme.

3. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: The external loads may act in the following ways: concentrated load in the middle of the span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span.

4. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: The deflection of the beam model due to bending deformation under different loads is given by the formula: in, They are the deflections of the hollow beam caused by bending deformation under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span, respectively. P is the concentrated load, q is the concentration of the uniformly distributed load, and L is the calculated span of the simply supported beam.

5. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: The stiffness reduction factor caused by shear deformation of the truss web under different loads includes the following formulas: in, are the stiffness reduction factors caused by shear deformation of the truss web under the concentrated load at the mid-span, the symmetrical load at two points at 1 / 4 span, and the uniform load at the full span; α = E c / E s is the ratio of the elastic modulus of the concrete top and bottom plates to the elastic modulus of the truss web; L is the calculated span of the simply supported beam, I0 is the bending moment of inertia of the truss web steel-concrete composite beam section, N is the number of half-span intervals, N' is the number of truss webs from the calculated section to the support, A s is the cross-sectional area of ​​the truss web, h s is the height of the truss web member, and θ is the inclination angle of the truss web member.

6. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: The stiffness reduction factor caused by the slip effect at the steel-concrete connection interface is calculated using the following formula: in, are the stiffness reduction coefficients caused by the sliding effect under the concentrated load at the mid-span, the symmetrical load at two points in the 1 / 4 span, and the uniformly distributed load at the full span, η is the coefficient related to the geometric parameters, and b is the distance from the loading point to the support.

7. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that: The formula for calculating the stiffness reduction factor caused by local deformation of the node includes: in, are the stiffness reduction factors under the concentrated load at mid-span, the symmetrical load at two points on the quarter span, and the uniform load on the full span, respectively. d is the internode distance, E c is the elastic modulus of the material, I j is the section inertia of the concrete slab within the transverse width of the single-node flange plate.

8. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 5, 6 or 7, characterized in that ,The equivalent bending stiffness of the composite beam is calculated by the following formula: in They are the equivalent bending stiffness of the composite beam under concentrated load in the mid-span, symmetrical load at two points in the 1 / 4 span, and uniformly distributed load in the full span.

9. The method for calculating the deflection of a truss-web steel-concrete composite beam according to claim 1 is characterized in that , the mid-span deflection of a simply supported beam under the action of a concentrated load at the mid-span, a symmetrical load at two points on a quarter span, and a uniformly distributed load at the full span are: in, and They are the mid-span deflection of a simply supported beam under concentrated load at the mid-span, symmetrical loading at two points on a quarter span, and uniformly distributed load on the full span.

10. A deflection calculation system for truss-web steel-concrete composite beams, characterized in that , the system comprises: The calculation scheme acquisition module constructs a simplified mechanical model of the truss-web steel-concrete composite beam, determines the calculation assumptions, and obtains the calculation scheme; A load mode determination module is used to determine the action mode of the external load on the truss-web steel-concrete composite beam; A basic parameter determination module, which determines the basic calculation parameters of the simplified mechanical model according to the calculation assumption scheme and the load action mode; The reduction coefficient calculation module calculates the stiffness reduction coefficients caused by the shear deformation of the truss web, the slip effect of the steel-concrete connection interface, and the local deformation of the node of the simply supported beam under different loads according to the action mode; An equivalent stiffness calculation module calculates the equivalent bending stiffness of the truss-web composite beam according to the basic calculation parameters and the stiffness reduction coefficient under different loads; The composite beam deflection calculation module calculates the deflection of the truss-web steel-concrete composite beam under different loads according to the equivalent bending stiffness and basic calculation parameters.

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