A method for determining the bearing capacity of asymmetrically constrained statically indeterminate reinforced concrete beams

Abstract

The present invention discloses a method for determining the bearing capacity of an asymmetric constrained indeterminate reinforced concrete beam. The method comprises the following steps: calculating the bending moment of the fixed section and reducing it, taking the moment at the hinged end support to establish an equilibrium equation; (4) based on the bending moment of the fixed section and the shear force at the fixed end loading point, establishing an internal force equilibrium equation for the fixed end compression rod-tension rod model, and obtaining the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component; (5) based on the shear force at the hinged end loading point, establishing an internal force equilibrium equation for the hinged end compression rod-tension rod model, and obtaining the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component; (6) calculating the plastic ultimate bearing capacity of each component and using it as the load borne by each component, calculating multiple P values, and taking the minimum P value as the ultimate bearing capacity of the reinforced concrete beam. The present invention determines the failure mode of the component by determining the location of the damaged component.

Description

Technical Field

[0001] The invention relates to a method for determining the bearing capacity of an asymmetric constrained statically indeterminate reinforced concrete beam, and belongs to the technical field of reinforced concrete beam bearing capacity calculation. Background Art

[0002] The strut-tie model (STM) is a predecessor of the classic truss model independently proposed by Ritter in 1899 and Mörsch in 1902. Schlaich et al. and Marti refined the STM and expanded its application, making it a universal, unified design method. Schlaich et al. proposed arranging the struts and tie rods based on the principal stress distribution derived from elastic analysis. This design reduces the redistribution of internal forces after cracking and the required ductile deformation, thereby providing sufficient bearing capacity and good normal service performance. Since then, the STM has been widely used in the bearing capacity prediction and reinforcement design of D-zone structures, such as deep beams, corbels, tongue-and-groove beams, beam-column joints, anchorage zones, and pile foundation caps. STM has been adopted by major European and American concrete design codes for reinforcement design and ultimate bearing capacity calculations in D zones, such as the American code ACI 318-14, the European code Eurocode 2, the Canadian code CSA A23.3-14, the U.S. Department of Transportation AASHTO LRFD Bridge Design Specifications (2017), and the International Federation of Structural Concrete fib Model Code 2010.

[0003] STM equates the complex stress flow in deep beams to uniaxially loaded rod elements. The axial forces borne by compression rods and tension rods are the resultant compressive and tensile stresses, respectively, and the intersection of tension rods and compression rods is a node (area). Tension rods, compression rods, and nodes are the three elements that make up the STM and share the external load. The stress field set by the STM satisfies both equilibrium and plasticity conditions. The equilibrium condition refers to the equilibrium between the structural stress distribution and the applied load under limit conditions that meet boundary conditions. The plasticity condition means that the stress at any part of the structure does not exceed the strength of the material. The corresponding load is called the acceptable load or static allowable load and is always less than the true plastic limit load.

[0004] At present, most domestic and foreign scholars use STM to calculate the bearing capacity of deep beams and short beams in their research. However, most of the STMs used are suitable for symmetrical constraints without considering the end shear force and section bending moment. The use of ordinary STM has certain constraints for actual working conditions and cannot meet the internal force equilibrium conditions of the component when the constraints at both ends are different, which in turn affects the reliability of the calculation results. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for determining the bearing capacity of an asymmetric constrained indeterminate reinforced concrete beam.

[0006] Preferably, the present invention provides a method for determining the bearing capacity of an asymmetrically constrained statically indeterminate reinforced concrete beam, comprising: (1) determining the cross-sectional dimensions, reinforcement information, and material strengths of the steel bars and concrete of the reinforced concrete beam;

[0007] (2) Determine the loading point position of the reinforced concrete beam, establish a compression rod-tension rod model, and determine the dimensions of each component, including the width of the compression rod end at the fixed end, the height of the upper and lower node areas at the fixed end, the width of the upper and lower node areas at the fixed end, the width of the compression rod end at the hinged end, the height of the upper and lower node areas at the hinged end, and the width of the upper and lower node areas at the hinged end;

[0008] (3) Calculate the bending moment of the fixed section and reduce it, then take the moment at the hinged end support to establish the equilibrium equation;

[0009] (4) Considering the bending moment of the fixed section and the shear force at the loading point of the fixed end, the internal force equilibrium equation of the fixed end compression rod-tension rod model is established. The internal force equilibrium equation is combined with the equilibrium equation obtained in step (3) to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component;

[0010] (5) Considering the shear force at the loading point of the hinged end, the internal force equilibrium equation of the hinged end compression rod-tension rod model is established, and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component is obtained;

[0011] (6) Calculate the plastic ultimate bearing capacity of each component and use it as the load borne by each component. Substitute it into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5). Calculate multiple P values ​​and take the smallest P value as the ultimate bearing capacity of the reinforced concrete beam.

[0012] Preferably, in step (3), the bending moment of the fixed section is calculated and reduced, and then the equilibrium equation is established by taking the moment at the hinged end support, including:

[0013] When the fixed end is completely fixed, the bending moment of the fixed section M The calculation formula is:

[0014] ,

[0015] Where β represents the ratio of the distance from the left loading point to the right edge of the fixed support to the effective span length, P is the external load acting on the loading point, and L is the effective span length;

[0016] In the component, the bending moment at the hinged end is 0, and the equilibrium equation is established by taking the moment of the hinged end support:

[0017] ,

[0018] in, F l is the reaction force of the left fixed support, F r is the reaction force of the right hinged support, M is the bending moment at the fixed section, η is the bending moment reduction factor of the fixed section.

[0019] Preferably, in step (4), the bending moment of the fixed section is considered ηM Shear force at the loading point of the fixed end F v1 , the internal force equilibrium equation is established for the fixed end compression rod-tension rod model. The internal force equilibrium equation is combined with the equilibrium equation to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component, including:

[0020] The internal force analysis of the fixed end tie rod-compression rod model is based on the internal force balance condition:

[0021] ,

[0022] in, F c1 is the lateral pressure on the top node of the reinforced concrete beam, F t1 is the steel bar tension at the bottom node of the reinforced concrete beam, d is the height from the midpoint of the compression zone to the bottom longitudinal reinforcement of the reinforced concrete beam, a 1 is the distance from the loading point to the fixed end support;

[0023] in, ,

[0024] Solving the internal force equilibrium equation, we can obtain the unilateral concentrated load P borne by the reinforced concrete beam corresponding to the failure of the top node and the bottom longitudinal reinforcement of the fixed end:

[0025]

[0026] Where, P nt1 is the STM bearing capacity corresponding to the failure of the top node of the fixed end, P bT1 is the STM bearing capacity corresponding to the failure of the longitudinal reinforcement at the bottom of the fixed end;

[0027] Take two node areas for force analysis and obtain the following from the internal force equilibrium condition:

[0028]

[0029] in, F sb1 is the axial force of the fixed end diagonal compression rod acting on the bottom node of the reinforced concrete beam, F st1 is the axial force of the fixed end diagonal compression rod acting on the top node of the reinforced concrete beam, F tm 、 F cm is the bending moment of the fixed section ηM The equivalent internal force, F tm is the tension of the upper longitudinal reinforcement, F cm is the lateral concrete pressure on the bottom node of the reinforced concrete beam, θ1 is the angle between the axis of the fixed end compression rod and the longitudinal reinforcement;

[0030] Substitution F v1 、F l 、 P nt1 、P bT1 The relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component at the fixed end is obtained:

[0031]

[0032]

[0033]

[0034]

[0035] Where, P st1 、 P sb1 、 P nb 、 P tT They are the STM bearing capacities corresponding to the failure of the upper end of the compression rod, the lower end of the compression rod, the bottom node and the top longitudinal reinforcement at the fixed end.

[0036] Prior to step 5, consider the shear force at the loading point of the hinge end F v2 , the internal force equilibrium equation is established for the hinged end compression rod-tension rod model, and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component is obtained, including:

[0037] The internal force analysis of the hinged end tie rod-compression rod model is based on the internal force balance condition:

[0038] ,

[0039] in, F c2 is the lateral pressure on the node at the right loading point, F t2 is the tension of the bottom longitudinal reinforcement on the right loading point section, F sb2 is the axial force of the hinged end diagonal compression rod acting on the bottom node, F st2 is the axial force of the hinged end diagonal compression rod acting on the top node, θ 2 is the angle between the axis of the compression rod at the hinged end and the longitudinal reinforcement;

[0040] Substitute into step 4 F v1 The relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component at the hinged end is obtained by using the formula:

[0041] ,

[0042] ,

[0043] ,

[0044] ,

[0045] Where, P nt2 、 P bT2 、 P st2 、 P sb2 are the STM bearing capacities corresponding to the destruction of the top node of the hinged end, the bottom longitudinal reinforcement, the upper end of the compression rod and the lower end of the compression rod.

[0046] Preferably, in step (6), the plastic ultimate bearing capacity of each component is calculated and used as the load borne by each component, and is substituted into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5), and multiple P values ​​are calculated, and the smallest P value is taken as the ultimate bearing capacity of the reinforced concrete beam, including:

[0047] Calculate the nominal load-bearing capacity of each component:

[0048] Compression rod bearing capacity ( Fsb 、 F st ): ,

[0049] Node bearing capacity ( F c 、 F cm ): ,

[0050] Tie rod bearing capacity ( F t 、 F tm ): ,

[0051] in, F cs 、 F cn 、 F t are the nominal bearing capacities of compression rods, nodes and tension rods respectively; A cs 、 A cn 、 A tS are the area of ​​the compression rod end, the area of ​​the lateral compression zone of the node and the cross-sectional area of ​​the bottom tension reinforcement; f ce is the effective compressive strength of concrete; β s is the effective coefficient of compressive strength of compression rod concrete, referred to as compression rod effective coefficient; f c ' is the compressive strength of concrete; β n is the effective coefficient of the node concrete compressive strength; f y is the yield strength of steel bars;

[0052]

[0053] Calculated P nt1 、 P bT1 、 P st1 、 P sb1 、 P nb 、 P tT 、 P nt2 、 P bT2 、 Pst2 、 P sb2 , take the minimum value P min As the ultimate bearing capacity of reinforced concrete beams.

[0054] Preferably, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any one of the methods described in the first aspect when executing the program.

[0055] Preferably, the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any one of the methods described in the first aspect when executed by a processor.

[0056] The beneficial effects achieved by the present invention are:

[0057] The present invention provides a method for determining the bearing capacity of an asymmetrically constrained, statically indeterminate reinforced concrete beam. Based on the existing strut-tension model, the internal force equilibrium equation of the model is re-established in the asymmetrically constrained, statically indeterminate reinforced concrete beam, taking into account the bending moment of the fixed surface section and the shear force of the loading point section. This equation then determines the relationship between the component bearing capacity P and the bearing capacity of each element in the strut-tension model. The ultimate bearing capacity of each element is then substituted to obtain multiple P values, with the minimum value taken as the component bearing capacity. Compared to existing strut-tension models, the present method is applicable to more complex working conditions and can determine the component failure mode by determining the location of the damaged element. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0059] Figure 1 Schematic diagram of a compression rod-tension rod model of a reinforced concrete beam with one end fixed and the other end hinged in the present invention;

[0060] Figure 2 is the bending moment diagram of the reinforced concrete beam in the present invention;

[0061] Figure 3 Schematic diagram of the internal force of the compression rod-tension rod model at the fixed end of the present invention;

[0062] Figure 4 Schematic diagram of the internal force situation in the top node area of ​​the compression rod-tension rod model at the fixed end of the present invention;

[0063] Figure 5Schematic diagram of the internal force situation in the bottom node area of ​​the compression rod-tension rod model at the fixed end of the present invention;

[0064] Figure 6 Schematic diagram of the internal force of the compression rod-tension rod model at the hinge end of the present invention;

[0065] Figure 7 Schematic diagram of the internal forces in the top node area of ​​the compression rod-tension rod model at the hinged end of the present invention;

[0066] Figure 8 Schematic diagram of the internal forces in the bottom node area of ​​the compression rod-tension rod model at the hinged end of the present invention. DETAILED DESCRIPTION

[0067] To facilitate the technical solution of the application, some concepts involved in this application are first explained below.

[0068] See also Figure 1 ,This application discloses a method for determining the bearing capacity of an asymmetrically constrained statically indeterminate reinforced concrete beam, comprising the following steps: (1) determining the cross-sectional dimensions, reinforcement information, and material strength of the steel bars and concrete of the reinforced concrete beam;

[0069] (2) Determine the loading point position of the reinforced concrete beam, establish a compression rod-tension rod model, and determine the dimensions of each component, including the width of the compression rod end at the fixed end, the height of the upper and lower node areas at the fixed end, the width of the upper and lower node areas at the fixed end, the width of the compression rod end at the hinged end, the height of the upper and lower node areas at the hinged end, and the width of the upper and lower node areas at the hinged end;

[0070] (3) Calculate the bending moment of the fixed section and reduce it, then take the moment at the hinged end support to establish the equilibrium equation;

[0071] (4) Considering the bending moment of the fixed section and the shear force at the loading point of the fixed end, the internal force equilibrium equation of the fixed end compression rod-tension rod model is established. The internal force equilibrium equation is combined with the equilibrium equation obtained in step (3) to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component;

[0072] (5) Considering the shear force at the loading point of the hinged end, the internal force equilibrium equation of the hinged end compression rod-tension rod model is established, and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component is obtained;

[0073] (6) Calculate the plastic ultimate bearing capacity of each component and use it as the load borne by each component. Substitute it into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5). Calculate multiple P values ​​and take the smallest P value as the ultimate bearing capacity of the reinforced concrete beam.

[0074] In step (3), the bending moment of the fixed section is calculated and reduced, and then the equilibrium equation is established by taking the moment at the hinged end support, including:

[0075] When the fixed end is completely fixed, the bending moment of the fixed section M The calculation formula is:

[0076] ,

[0077] Where β represents the ratio of the distance from the left loading point to the right edge of the fixed support to the effective span length, P is the external load acting on the loading point, and L is the effective span length;

[0078] Considering the incomplete connection of the fixed end, the bending moment of the fixed section is reduced and the reduction coefficient is taken η , M g =ηM;

[0079] In the component, the bending moment at the hinged end is 0, and the equilibrium equation is established by taking the moment of the hinged end support:

[0080] ,

[0081] in, F l is the reaction force of the left fixed support, F r is the reaction force of the right hinged support, M is the bending moment at the fixed section, η is the bending moment reduction factor of the fixed section.

[0082] In step (4), based on the bending moment of the fixed section and the shear force at the loading point of the fixed end, the internal force balance equation of the fixed end compression rod-tension rod model is established. The internal force balance equation is combined with the balance equation to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component, including:

[0083] The internal force analysis of the fixed end tie rod-compression rod model is based on the internal force balance condition:

[0084] ,

[0085] in, F c1 is the lateral pressure on the top node of the reinforced concrete beam, F t1 is the steel bar tension at the bottom node of the reinforced concrete beam, d is the height from the midpoint of the compression zone to the bottom longitudinal reinforcement of the reinforced concrete beam, a 1 is the distance from the loading point to the fixed end support;

[0086] in, ,

[0087] Solving the internal force equilibrium equation, we can obtain the unilateral concentrated load P borne by the reinforced concrete beam corresponding to the failure of the top node and the bottom longitudinal reinforcement of the fixed end:

[0088]

[0089] Where, P nt1 is the STM bearing capacity corresponding to the failure of the top node of the fixed end, P bT1 is the STM bearing capacity corresponding to the failure of the longitudinal reinforcement at the bottom of the fixed end;

[0090] Take two node areas for force analysis and obtain the following from the internal force equilibrium condition:

[0091]

[0092] in, F sb1 is the axial force of the fixed end diagonal compression rod acting on the bottom node of the reinforced concrete beam, F st1 is the axial force of the fixed end diagonal compression rod acting on the top node of the reinforced concrete beam, F tm 、 F cm is the bending moment of the fixed section ηM The equivalent internal force, F tm is the tension of the upper longitudinal reinforcement, F cm is the lateral concrete pressure on the bottom node of the reinforced concrete beam, θ1 is the angle between the axis of the fixed end compression rod and the longitudinal reinforcement;

[0093] Substitution F v1 、F l 、 P 1 、P 2 The relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component at the fixed end is obtained:

[0094]

[0095]

[0096]

[0097] ,

[0098] Where, P st1 、 P sb1 、 P nb 、 P tT They are the STM bearing capacities corresponding to the failure of the upper end of the compression rod, the lower end of the compression rod, the bottom node and the top longitudinal reinforcement at the fixed end.

[0099] In step (5), based on the shear force at the loading point of the hinged end, the internal force equilibrium equation of the hinged end compression rod-tension rod model is established to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component, including:

[0100] The internal force analysis of the hinged end tie rod-compression rod model is based on the internal force balance condition:

[0101] ,

[0102] Among them, F r is the reaction force of the right hinged support, F c2 is the lateral pressure on the node at the right loading point, F t2 is the tension of the bottom longitudinal reinforcement on the right loading point section, that is, the tension of the tie rod in the STM of the hinged end, F sb2 is the axial force of the hinged end diagonal compression rod acting on the bottom node, F st2 is the axial force of the hinged end diagonal compression rod acting on the top node, θ 2 is the angle between the axis of the compression rod at the hinged end and the longitudinal reinforcement;

[0103] Substitute into step (4) F v1 ,get:

[0104] ,

[0105] ,

[0106] ,

[0107] ,

[0108] Where, P nt2 、 P bT2 、 P st2 、 P sb2are the STM bearing capacities corresponding to the destruction of the top node of the hinged end, the bottom longitudinal reinforcement, the upper end of the compression rod and the lower end of the compression rod.

[0109] In step (6), the plastic ultimate bearing capacity of each component is calculated and used as the load borne by each component. The value is substituted into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5). Multiple P values ​​are calculated and the minimum P value is taken as the ultimate bearing capacity of the reinforced concrete beam, including:

[0110] Calculate the ultimate bearing capacity of each component:

[0111] Compression rod bearing capacity ( F sb 、F st ): ,

[0112] Node bearing capacity (F c 、F cm ): ,

[0113] Tie rod bearing capacity (F t 、F tm ): ,

[0114] in, F cs 、 F cn 、 F t are the nominal bearing capacities of compression rods, nodes and tension rods respectively; A cs 、 A cn 、 A tS are the area of ​​the compression rod end, the area of ​​the lateral compression zone of the node and the cross-sectional area of ​​the bottom tension reinforcement; f ce is the effective compressive strength of concrete; β s is the effective coefficient of compressive strength of compression rod concrete, referred to as compression rod effective coefficient; f c ' is the compressive strength of concrete; β n is the effective coefficient of the node concrete compressive strength; f y is the yield strength of steel bars; w s is the width of the pressure rod end, Calculate, h n With l n Respectively represent the height and width of the node area; h n Including CCC node area height h nt and CCT node area height h nb , h nt use calculate, h nb Take twice the distance from the longitudinal reinforcement to the edge of the concrete on the same side; b is the width of reinforced concrete specimen.

[0115] Compression rod effectiveness coefficient β s The value of is: 1) 1.0 for prismatic compression rods; 2) 0.75 for bottle-shaped compression rods with stirrups, otherwise 0.6; 3) 0.4 for compression rods located in tension members or in tension areas of members; 4) 0.6 for other cases; β n It is the effective coefficient of the node concrete compressive strength, referred to as the node effective coefficient.

[0116] Node areas are where compression rods intersect, or where compression rods and tension rods intersect. Depending on the number of tension rods and compression rods, they can be classified as compression-compression-compression (CCC) nodes, compression-compression-tension (CCT) nodes, and compression-tension-tension (CTT) nodes. CCC node areas are enclosed by compression rods or compression rods and pads, and are subject to "three-dimensional" compression in the plane. CCT node areas are anchored by one tension rod, and CTT node areas are anchored by two tension rods. Node effectiveness coefficient β s The values ​​are: 1) 1.0 for CCC nodes; 2) 0.8 for CCT nodes; 3) 0.6 for CTT nodes.

[0117] Calculated P nt1 、 P bT1 、 P st1 、 P sb1 、 P nb 、 P tT 、 P nt2 、 P bT2 、 P st2 、 P sb2 , take the minimum value Pmin As the ultimate bearing capacity of reinforced concrete beams:

[0118]

[0119] According to the above calculation method of the bearing capacity of each component, the P 1 ~ P 10 ,Pick P 1 ~ P 10 Minimum value P min As the ultimate bearing capacity of reinforced concrete beams.

[0120] In an embodiment of the present application, the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any of the above methods when executing the program.

[0121] In an embodiment of the present application, the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of any of the above methods when executed by a processor.

[0122] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0123] Other embodiments of the present invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not invented herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0124] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of this application in detail. It should be understood that the above are only specific implementation methods of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of this application should be included in the scope of protection of this application.

Claims

1. A method for determining the bearing capacity of an asymmetrically constrained statically indeterminate reinforced concrete beam, characterized in that: include: (1) Determine the cross-sectional dimensions, reinforcement information, and material strength of steel and concrete for reinforced concrete beams; (2) Determine the loading point position of the reinforced concrete beam, establish a compression rod-tension rod model, and determine the dimensions of each component, including the width of the compression rod end at the fixed end, the height of the upper and lower node areas at the fixed end, the width of the upper and lower node areas at the fixed end, the compression rod at the hinged end, the height of the upper and lower node areas at the hinged end, and the width of the upper and lower node areas at the hinged end; (3) Calculate the bending moment of the fixed section and reduce it, then take the moment at the hinged end support to establish the equilibrium equation; (4) Considering the bending moment of the fixed section and the shear force at the loading point of the fixed end, the internal force equilibrium equation of the fixed end compression rod-tension rod model is established. The internal force equilibrium equation is combined with the equilibrium equation obtained in step (3) to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component; (5) Considering the shear force at the loading point of the hinged end, the internal force equilibrium equation of the hinged end compression rod-tension rod model is established, and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component is obtained; (6) Calculate the plastic ultimate bearing capacity of each component and use it as the load borne by each component, substitute it into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5), calculate multiple P values, and take the smallest P value as the ultimate bearing capacity of the reinforced concrete beam; In step (3), the bending moment of the fixed section is calculated and reduced, and then the equilibrium equation is established by taking the moment at the hinged end support, including: When the fixed end is completely fixed, the bending moment of the fixed section M The calculation formula is: ， Where β represents the ratio of the distance from the left loading point to the right edge of the fixed support to the effective span length, P is the external load acting on the loading point, and L is the effective span length; In the component, the bending moment at the hinged end is 0, and the equilibrium equation is established by taking the moment of the hinged end support: ， in, F l is the reaction force of the left fixed support, M is the bending moment at the fixed section, η is the bending moment reduction factor of the fixed section; In step (4), consider the bending moment of the fixed section ηM Shear force at the loading point of the fixed end F v1 , the internal force equilibrium equation is established for the fixed end compression rod-tension rod model. The internal force equilibrium equation is combined with the equilibrium equation to obtain the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component, including: The internal force analysis of the fixed end tie rod-compression rod model is based on the internal force balance condition: ， in, F c1 is the lateral pressure on the top node of the reinforced concrete beam, F t1 is the steel bar tension at the bottom node of the reinforced concrete beam, d is the height from the midpoint of the compression zone to the bottom longitudinal reinforcement of the reinforced concrete beam, a 1 is the distance from the loading point to the fixed end support; in, , Solving the internal force equilibrium equation, we can obtain the unilateral concentrated load P borne by the reinforced concrete beam corresponding to the failure of the top node and the bottom longitudinal reinforcement of the fixed end: Where, P nt1 is the STM bearing capacity corresponding to the failure of the top node of the fixed end, P bT1 is the STM bearing capacity corresponding to the failure of the longitudinal reinforcement at the bottom of the fixed end; Take two node areas for force analysis and obtain the following from the internal force equilibrium condition: in, F sb1 is the axial force of the fixed end diagonal compression rod acting on the bottom node of the reinforced concrete beam, F st1 is the axial force of the fixed end diagonal compression rod acting on the top node of the reinforced concrete beam, F tm 、 F cm is the bending moment of the fixed section ηM The equivalent internal force, F tm is the tension of the upper longitudinal reinforcement, F cm is the lateral concrete pressure on the bottom node of the reinforced concrete beam, θ1 is the angle between the axis of the fixed end compression rod and the longitudinal reinforcement; Substitution F v1 、F l 、 P nt1 、P bT1 The relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component at the fixed end is obtained: ， Where, P st1 、 P sb1 、 P nb 、 P tT are the STM bearing capacities corresponding to the failure of the upper end of the compression rod, the lower end of the compression rod, the bottom node and the top longitudinal reinforcement at the fixed end; In step (5), the shear force at the loading point of the hinged end is considered F v2 , the internal force equilibrium equation is established for the hinged end compression rod-tension rod model, and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component is obtained, including: The internal force analysis of the hinged end tie rod-compression rod model is based on the internal force balance condition: ， in, F r is the reaction force of the right hinged support, F c2 is the lateral pressure on the node at the right loading point, F t2 is the tension of the bottom longitudinal reinforcement on the right loading point section, F sb2 is the axial force of the hinged end diagonal compression rod acting on the bottom node, F st2 is the axial force of the hinged end diagonal compression rod acting on the top node, θ 2 is the angle between the axis of the hinged end compression rod and the longitudinal reinforcement; substitute into step (4) F v1 The relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component at the hinged end is obtained by using the formula: ， ， ， , where P nt2 、 P bT2 、 P st2 、 P sb2 are the STM bearing capacities corresponding to the destruction of the top node of the hinged end, the bottom longitudinal reinforcement, the upper end of the compression rod and the lower end of the compression rod.

2. The method for determining the bearing capacity of an asymmetrically constrained statically indeterminate reinforced concrete beam according to claim 1, wherein: In step (6), the plastic ultimate bearing capacity of each component is calculated and used as the load borne by each component. It is substituted into the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (4) and the relationship between the unilateral concentrated load P borne by the reinforced concrete beam and the load borne by each component in step (5). Multiple P values ​​are calculated and the minimum P value is taken as the ultimate bearing capacity of the reinforced concrete beam, including: Calculate the nominal load-bearing capacity of each component: Compression rod bearing capacity ( F sb 、 F st ): , Node bearing capacity ( F c 、 F cm ): , Tie rod bearing capacity ( F t 、 F tm ): , in, F cs 、 F cn 、 F t are the nominal bearing capacities of compression rods, nodes and tension rods respectively; A cs 、 A cn 、 A ts are the area of ​​the compression rod end, the area of ​​the lateral compression zone of the node and the cross-sectional area of ​​the bottom tension reinforcement; f ce is the effective compressive strength of concrete; β s is the effective coefficient of compressive strength of compression rod concrete, referred to as compression rod effective coefficient; f c ' is the compressive strength of concrete; β n is the effective coefficient of the node concrete compressive strength; f y is the yield strength of steel bars; Calculated P nt1 、 P bT1 、 P st1 、 P sb1 、 P nb 、 P tT 、 P nt2 、 P bT2 、 P st2 、 P sb2 , take the minimum value P min As the ultimate bearing capacity of reinforced concrete beams.

3. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method according to any one of claims 1 to 2 are implemented.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 2 are implemented.

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