Method and system for calculating shrinkage and creep effect of cast-in-place concrete beam structure

Abstract

This application relates to a method for calculating the shrinkage and creep effect of batch-cast concrete beam structures, comprising: determining the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure to calculate the primary shrinkage and creep strain under a certain load step; calculating the elastic strain of the total shrinkage and creep effect under that load step; calculating the self-stress elastic strain generated by the shrinkage and creep of concrete at different ages under that load step; and using the sum of the self-stress elastic strain and the elastic strain of the total shrinkage and creep effect as the elastic strain for calculating the primary shrinkage and creep effect in subsequent load steps. This application calculates the primary shrinkage and creep strain and the self-stress elastic strain generated by shrinkage and creep based on the equivalent section characteristic parameters of concrete at different ages, separating the calculation into the deformation of concrete at different ages, thereby achieving accurate calculation of the shrinkage and creep effect of batch-cast concrete beam structures.

Description

Technical Field

[0001] This invention relates to the field of finite element technology, specifically to a method and system for calculating the shrinkage and creep effect of batch-cast concrete beam structures. Background Technology

[0002] Shrinkage and creep are collective terms for the two phenomena of shrinkage and creep that occur in concrete structures under stress or environmental factors. Batch-cast concrete beams contain concrete at various loading ages. Concrete at different loading ages has different creep coefficients and shrinkage strains at the same calculation time. This causes shrinkage and creep to generate self-stress, and the strain generated by this self-stress further induces creep. Therefore, the calculation process for the shrinkage and creep effect of batch-cast concrete beam structures is quite complex.

[0003] In related technologies, structural calculations are mainly performed using the finite element method, which often employs a multi-element simulation method. Each element simulates concrete at a certain age, and the elements are connected by rigid arms. However, when the centroid distances of the cross sections of concrete at different ages differ significantly, the above simulation method can cause large errors and result in low calculation accuracy. Summary of the Invention

[0004] This application provides a method and system for calculating the shrinkage and creep effect of batch-cast concrete beam structures, solving the technical problems of large errors and low calculation accuracy caused by the use of multi-element simulation methods in related technologies.

[0005] This application provides a method for calculating the shrinkage and creep effect of a batch-cast concrete beam structure, which includes the following steps: Based on the batch-cast concrete beam structure, the equivalent section characteristic parameters of concrete at different ages are determined in order to calculate the strain of the first effect of shrinkage and creep under a certain load step. Calculate the elastic strain of the total shrinkage and creep effect under this load step; Calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under this load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the first effect of shrinkage and creep in subsequent load steps.

[0006] In one embodiment, the step of determining the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, in order to calculate the shrinkage and creep strain under a certain load step, includes: The cross-sectional properties of concrete materials of other ages, except for the first age concrete material, are converted to the cross-sectional properties of the first age concrete material to determine the converted cross-sectional property parameters of the concrete of different ages. The shrinkage and creep first-order effect internal force in the batch-cast concrete beam structure is set to 0. Based on the converted section characteristic parameters of the concrete at different ages, the shrinkage and creep first-order effect strain under a certain load step is calculated.

[0007] In one embodiment, calculating the shrinkage and creep strain under a certain load step based on the converted section characteristic parameters of concrete at different ages includes: The calculation formula is: ; ; ; in, These are the axial strain and the circumferential strain of the first-order effect of shrinkage creep, respectively. y Axis bending curvature and circumference z Shaft bending curvature; The area and radius of concrete materials at different ages are converted to the area of ​​concrete materials at the first age, respectively. y Axial moment of inertia, about z Moment of inertia of the axis; The first i Area of ​​concrete material at different ages, winding y Shaft static moment, about z Shaft static moment, about y Axial moment of inertia, about z Moment of inertia, product of inertia; n The number of materials at different ages; For the first i The elastic modulus ratio of the first-age concrete material to the first-age concrete material; For the first i The increase in shrinkage strain of concrete materials at a certain age over the calculation period; m To calculate the number of load steps applied before the start of the time period; For the first i Seedling age materials j The creep coefficient increment during the calculation period; The first j The first loading caused the i Elastic axial strain and circumferential strain of concrete materials at different ages y Axis bending curvature and circumference z Axis bending curvature.

[0008] In one embodiment, calculating the elastic strain for the total shrinkage and creep effect under the load step includes: The equivalent nodal load of shrinkage and creep effect is obtained based on the strain of the first effect of shrinkage and creep. The equivalent nodal loads of shrinkage and creep in the batch-cast concrete beam structure are aggregated into a total load vector. The strain results of the shrinkage and creep effect are calculated and used as the elastic strain of the total shrinkage and creep effect under the load step.

[0009] In one embodiment, obtaining the equivalent nodal load of shrinkage and creep effect based on the primary effect strain of shrinkage and creep includes: When the beam elements in the batch-cast concrete beam structure are constant cross-section elements... The equivalent nodal load of shrinkage and creep effect is calculated based on the strain of the first-order shrinkage and creep effect.

[0010] In one embodiment, obtaining the equivalent nodal load of shrinkage and creep effect based on the primary effect strain of shrinkage and creep includes: When the beam elements in the batch-cast concrete beam structure are variable cross-section elements The strain of the first effect of shrinkage and creep inside the beam element is calculated by linear interpolation of the strain of the first effect of shrinkage and creep at the end nodes of the beam element, so as to obtain the relative displacement of the end nodes of the beam element. The equivalent nodal load for shrinkage and creep is calculated based on the relative displacement.

[0011] In one embodiment, calculating the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under the load step includes: Based on the plane section assumption, calculate the first... i Materials of different ages in cross-sectional coordinates ( y,z The formula for calculating the elastic strain of the self-stress at point () is: ; in, ; ; .

[0012] In one embodiment, the step of using the sum of the self-stressed elastic strain and the elastic strain of the total shrinkage and creep effect as the elastic strain for calculating the first-order effect of shrinkage and creep in subsequent load steps includes: ; ; ; in, The elastic strain is the total elastic strain due to shrinkage and creep under this load step. This represents the elastic strain due to the primary effect of shrinkage and creep under subsequent load steps.

[0013] This application also provides a system for calculating the shrinkage and creep effect of batch-cast concrete beam structures, applying the method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in any of the above claims, which includes: The primary effect strain calculation module is configured to: determine the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, in order to calculate the primary effect strain of shrinkage and creep under a certain load step; The total effect strain calculation module is configured to calculate the elastic strain of the total shrinkage and creep effect under this load step. The self-stress elastic strain calculation module is configured to: calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under the load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the first effect of shrinkage and creep in subsequent load steps.

[0014] The beneficial effects of the technical solutions provided in this application include: This application provides a method for calculating the shrinkage and creep effect of batch-cast concrete beam structures. Based on the converted section characteristic parameters of concrete at different ages, it calculates the primary effect strain of shrinkage and creep and the elastic strain of self-stress generated by shrinkage and creep. The calculation process separates the deformation of concrete at different ages for calculation, thereby achieving accurate calculation of the shrinkage and creep effect of batch-cast concrete beam structures. Compared with related technologies that use multi-element simulation methods, the batch-cast concrete beam structure method provided in this application treats concrete at different ages as a single unit, avoiding the problem of large centroid distances and effectively reducing errors. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 (A) is a schematic diagram of a batch-cast concrete beam structure along the length of the beam unit in one embodiment of the present invention.

[0017] Figure 1 (B) is a schematic diagram of a batch-cast concrete beam structure along the cross-sectional direction of the beam unit in one embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the construction state of a concrete beam structure poured in batches according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] This application provides a method for calculating the shrinkage and creep effect of batch-cast concrete beam structures, which can solve the technical problems of large errors and low calculation accuracy caused by the use of multi-element simulation methods in related technologies.

[0021] This embodiment provides a method for calculating the shrinkage and creep effect of a batch-cast concrete beam structure, which includes the following steps: Step S1: Determine the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, so as to calculate the strain of the first effect of shrinkage and creep under a certain load step. Step S2: Calculate the elastic strain of the total shrinkage and creep effect under this load step; Step S3: Calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under this load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the primary effect of shrinkage and creep in subsequent load steps.

[0022] This embodiment provides a method for calculating the shrinkage and creep effect of batch-cast concrete beam structures. Based on the converted section characteristic parameters of concrete at different ages, it calculates the primary effect strain of shrinkage and creep and the elastic strain of self-stress generated by shrinkage and creep. The calculation process separates the deformation of concrete at different ages for calculation, thereby achieving accurate calculation of the shrinkage and creep effect of batch-cast concrete beam structures. Compared to related technologies that use multi-element simulation methods, the batch-cast concrete beam structure provided in this application treats concrete at multiple ages as a single unit, eliminating the problem of large centroid distances and effectively reducing errors.

[0023] The following provides a detailed explanation of each step.

[0024] In one embodiment, step S1, determining the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, to calculate the shrinkage and creep strain under a certain load step, includes: Step S11: Convert the cross-sectional properties of concrete materials of other ages, except for the first age concrete material, into the cross-sectional properties of the first age concrete material, so as to determine the converted cross-sectional property parameters of concrete of different ages. Step S12: Set the internal force of the shrinkage and creep first effect in the batch-cast concrete beam structure to 0, and calculate the strain of the shrinkage and creep first effect under a certain load step based on the converted section characteristic parameters of concrete at different ages.

[0025] In one embodiment, step S12, calculating the shrinkage and creep strain under a certain load step based on the converted section characteristic parameters of concrete at different ages, includes: The calculation formula is: ; ; ; in, These are the axial strain and the circumferential strain of the first-order effect of shrinkage creep, respectively. y Axis bending curvature and circumference z Shaft bending curvature; The area and radius of concrete materials at different ages are converted to the area of ​​concrete materials at the first age, respectively. y Axial moment of inertia, about z Moment of inertia of the axis; The first i Area of ​​concrete material at different ages, winding y Shaft static moment, about z Shaft static moment, about y Axial moment of inertia, about z Moment of inertia, product of inertia; n The number of materials at different ages; For the first i The elastic modulus ratio of the first-age concrete material to the first-age concrete material; For the first i The increase in shrinkage strain of concrete materials at a certain age over the calculation period; m To calculate the number of load steps applied before the start of the time period; For the first i Seedling age materials j The creep coefficient increment during the calculation period; The first j The first loading caused the i Elastic axial strain and circumferential strain of concrete materials at different ages y Axis bending curvature and circumference z Axis bending curvature.

[0026] The derivation process of the above scheme is as follows: Assuming the shrinkage and creep effect internal forces in a phased-cast concrete beam structure are zero, the following formula is obtained: Formula 1; Formula 2; Formula 3; in, N For unit axial force; M y To bypass y Axial bending moment; M z To bypass z Axial bending moment; For the first i The coordinates of concrete material at different ages in beam element sections ( y,z Shrinkage and creep strain at ( ) For the first i The elastic modulus of concrete materials at different ages.

[0027] By integrating concrete materials at different ages separately, the following formula is obtained: Equation 4; Formula 5; Formula 6; in, The cross-sectional properties of concrete materials at different ages are converted to those of concrete materials at the first age, hereinafter referred to as converted cross-sectional properties, as follows: ; ; ; ; ; .

[0028] If the origin of the cross-sectional coordinate system is the centroid of the transformed cross-section and the coordinate axes are the principal axes of inertia, then: ; ; The above formula then simplifies to: Formula 7; Formula 8; Formula 9.

[0029] No. i The formula for calculating the cumulative shrinkage and creep strain of concrete materials at a certain age over the calculation period is as follows: Formula 10.

[0030] Substituting equation 10 into equations 7, 8, and 9 yields the following equation: Formula 11; Equation 12; Formula 13.

[0031] By converting the integral term in the above equation into cross-sectional characteristic parameters, the formula for calculating the strain of the primary effect of shrinkage and creep can be derived: Equation 14; Formula 15; Formula 16.

[0032] in, ; ; ; ; ; , respectively i Area of ​​concrete material at different ages, winding y Shaft static moment, about z Shaft static moment, about y Axial moment of inertia, about z Axial moment of inertia and product of inertia; these parameters are inherent properties of the cross section and are independent of the stress state.

[0033] The above scheme assumes that shrinkage and creep do not cause internal forces. The linear equation system is used to calculate the strain of the first effect of shrinkage and creep, that is, the "free" deformation of the structure. The overall deformation is separated into the deformation of concrete materials at different ages. The deformation of concrete at each age (including axial strain and two flexural curvatures) is calculated by material and time period, which serves as the starting point for calculating self-stress strain.

[0034] In statically determinate structures, deformations caused by non-load factors such as shrinkage and creep (i.e., primary effects) do not generate internal forces. Therefore, when a batch-cast concrete beam structure is a statically determinate structure, the elastic strain of the total effect of shrinkage and creep is 0, meaning step S2 can be omitted.

[0035] In one embodiment, step S2, calculating the elastic strain of the total shrinkage and creep effect under the load step, includes: Step S21: Obtain the equivalent nodal load of shrinkage and creep effect based on the strain of the first effect of shrinkage and creep; Step S22: Collect the equivalent nodal loads of shrinkage and creep in the batch-cast concrete beam structure into a total load vector, calculate the strain result of shrinkage and creep effect, and use it as the elastic strain of the total shrinkage and creep effect under this load step.

[0036] In one embodiment, step S21, obtaining the equivalent nodal load of shrinkage and creep effect based on the first-order effect strain of shrinkage and creep, includes: When the beam element in a batch-cast concrete beam structure is a uniform cross-section element, that is, the cross-sections of the two ends of the beam element are the same. The equivalent nodal load of shrinkage and creep effect is calculated based on the strain of the first-order effect of shrinkage and creep.

[0037] The calculation formula is: Equation 17; Formula 18; Formula 19; in, F x This represents the equivalent axial force along the x-axis in the element coordinate system. Let be the bending moment about the y-axis in the element coordinate system. Let be the bending moment about the z-axis in the element coordinate system.

[0038] In one embodiment, step S21, obtaining the equivalent nodal load of shrinkage and creep effect based on the first-order effect strain of shrinkage and creep, includes: When the beam element in a batch-cast concrete beam structure is a variable cross-section element, that is, the cross-sections of the two ends of the beam element are different. The strain of the first effect of shrinkage and creep inside the beam element is calculated by linear interpolation of the strain of the first effect of shrinkage and creep at the end nodes of the beam element, so as to obtain the relative displacement of the end nodes of the beam element. The equivalent nodal load for shrinkage and creep is calculated based on relative displacement.

[0039] Specifically, the shrinkage and creep strain within the element is obtained by linear interpolation of the primary effect at the IJ end. The relative displacement at the IJ end is obtained based on the shrinkage and creep strain within the element. The element linear stiffness is multiplied by this displacement to obtain the equivalent nodal load of the shrinkage and creep effect.

[0040] Based on the above scheme, a method for calculating the elastic strain of the total shrinkage and creep effect of different types of beam elements is given.

[0041] In one embodiment, step S3, calculating the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under the load step, includes: Based on the plane section assumption, calculate the first... i Materials of different ages in cross-sectional coordinates ( y,z The formula for calculating the elastic strain of the self-stress at point () is: ; in, ; ; .

[0042] Specifically, the plane section assumption means that after a beam undergoes bending deformation, the cross section that was originally perpendicular to the beam axis remains a plane after deformation and is still perpendicular to the deformed beam axis.

[0043] The derivation process of the above calculation formula is as follows: Based on the plane section assumption, the first... i Materials of different ages in cross-sectional coordinates ( y,z The formula for calculating the elastic strain of the self-stress at point () is: Formula 20; Substituting equation 10 into equation 20, we obtain the following formula: Equation 21; make , , Then equation 21 simplifies to: Equation 22.

[0044] In one embodiment, step S3, using the sum of the elastic strain of the total shrinkage and creep effect and the elastic strain of the self-stress as the elastic strain for subsequent load steps to calculate the elastic strain of the first-order shrinkage and creep effect, includes: Equation 23; Equation 24; Formula 25; in, The elastic strain is the total elastic strain due to shrinkage and creep under this load step; This represents the elastic strain due to the primary effect of shrinkage and creep under subsequent load steps.

[0045] This application also provides a system for calculating the shrinkage and creep effect of batch-cast concrete beam structures, which applies the above-described method for calculating the shrinkage and creep effect of batch-cast concrete beam structures, and includes: The primary effect strain calculation module is configured to: determine the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, in order to calculate the primary effect strain of shrinkage and creep under a certain load step; The total effect strain calculation module is configured to calculate the elastic strain of the total shrinkage and creep effect under this load step. The self-stress elastic strain calculation module is configured to: calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under this load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the first effect of shrinkage and creep in subsequent load steps.

[0046] The functions of each module have been explained in the preceding text and will not be repeated here.

[0047] The following provides a specific example for illustration.

[0048] like Figure 1 and Figure 2 As shown, where, Figure 1 (A) is a schematic diagram of a batch-cast concrete beam structure along the length of the beam unit in one embodiment of the present invention. Figure 1 (B) is a schematic diagram of a batch-cast concrete beam structure along the cross-sectional direction of the beam unit in one embodiment of the present invention. Figure 2 This is a schematic diagram of the construction state of a concrete beam structure poured in batches according to an embodiment of the present invention.

[0049] This embodiment is a cantilever beam structure (statically determinate structure), with beam elements having uniform cross-sections. The elastic modulus of both concrete material 1 and concrete material 2 is taken as E=34500. MPa As shown in State 1 (external load exists but no self-stress): When concrete material 1 is poured and the beam's free end is subjected to 100 mm of stress at 10 days of age... KN m The bending moment; as shown in state 2 (no external load but with self-stress): after 90 days, concrete material 2 is poured and cured for 10 days; as shown in state 3: at 50 days of age of concrete material 2, the free end of the beam is subjected to 200... KN m The bending moment. Now we need to analyze the bending moment. 200KN m The stress state 100 days after the bending moment is as shown in state 4. For clarity of the invention, the self-weight effect is ignored.

[0050] Sectional properties of concrete material 1: Moment of inertia about its principal axes of inertia ,area Moment of inertia about the principal axes of inertia of the transformed section static moment about the principal axes of inertia of the transformed section , The cross-sectional properties of concrete material 2, besides... Apart from that, its other properties are the same as material 1. Equivalent section properties: , , ,

[0051] (1) Calculate the force state of state 1: State 1: Only concrete material 1 (i.e., the first age concrete material) is poured, and the free end of the beam is subjected to bending moment. (i.e., the first load step) but Its elastic axial strain, transformed to the converted section coordinate system, is: the centroidal axial strain of concrete material 1. .

[0052] The stress state of state 1 is the elastic axial strain and axial strain of the concrete material at the first age caused by the first load step. y Axis bending curvature and circumference z The axial curvatures are respectively: .

[0053] (2) Calculate the force state of state 2: State 2: For concrete material 1, the elastic strain has not changed; for concrete material 2 (i.e., the second age of concrete material), there is no external load, and concrete material 2 and concrete material 1 have just begun to bond, and have not yet generated shrinkage, creep, self-stress, and elastic strain. Therefore, the elastic strain of material 2 in this state is 0.

[0054] That is, the force state of state 2 is: .

[0055] (3) Calculate the force state of state 3: State 3: The elastic strain generated by the self-stress of shrinkage and creep exists between State 2 and State 3 (i.e., the second load step). (3.1) Calculate the strain of the first-order shrinkage creep effect from state 2 to state 3: Shrinkage strain increment of material 1 The creep coefficient increment corresponding to the first load step The shrinkage strain increment of material 2 (The calculation of the above increments is based on existing technology and will not be elaborated here.)

[0056] According to the calculation formula for the strain of the first effect of shrinkage and creep (i.e., Equation 14-16), we get: ; ; .

[0057] Solving the above system of equations yields the strain of the first-order shrinkage creep effect from state 2 to state 3: .

[0058] (3.2) Calculate the elastic strain of shrinkage creep self-stress from state 2 to state 3: Since this embodiment is a statically determinate structure, the calculation of elastic strain for the total effect of shrinkage and creep (i.e., Equations 17-19) is omitted. The self-stress elastic strain of concrete material 1 and concrete material 2 is obtained according to Equation 21.

[0059] ; ; ; ; ; .

[0060] According to Equation 22, the shrinkage and creep self-stresses of the top / bottom surfaces of concrete material 1 and concrete material 2 from state 2 to state 3 are calculated as follows: Material 1 Top Surface: ; Material 1 bottom surface: ; Material 2 Top Surface: ; Material 2 bottom surface: .

[0061] The self-stressed elastic strain caused by shrinkage and creep from state 2 to state 3 is taken as the effect of the second load step: ; .

[0062] (3.3) Calculate state 3 in 200 KN m The elastic strains of concrete material 1 and concrete material 2 under bending moment (third load step) are: .

[0063] (4) Calculate the force state of state 4: (4.1) Calculate the strain of the first-order shrinkage creep effect from state 3 to state 4: Shrinkage strain increment of material 1 The creep coefficient increment corresponding to the first load step The creep coefficient increment corresponding to the second load step The creep coefficient increment corresponding to the third load step The shrinkage strain increment of material 2 The creep coefficient increment corresponding to the second load step The creep coefficient increment corresponding to the third load step .

[0064] According to the calculation formula for the strain of the first effect of shrinkage and creep (i.e., Equation 14-16), we get: ; ; .

[0065] Solving the above system of equations yields the strain of the first-order shrinkage creep effect from state 3 to state 4: .

[0066] (4.2) Calculate the elastic strain of shrinkage creep self-stress from state 3 to state 4: The self-stress elastic strain of concrete material 1 and concrete material 2 is obtained according to Equation 21.

[0067] ; ; ; ; ; .

[0068] According to Equation 22, the shrinkage and creep self-stresses of the top / bottom surfaces of concrete materials 1 and 2 from state 3 to state 4 are calculated as follows: Material 1 Top Surface: ; Material 1 bottom surface: ; Material 2 Top Surface: ; Material 2 bottom surface: .

[0069] It should be noted that the sequence numbers of the embodiments in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not represent a sequential order, nor do they limit "first," "second," and "third" to different types.

[0070] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0071] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0072] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0073] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for calculating shrinkage and creep effects of a batched concrete beam structure, characterized by, It includes the following steps: Based on the batch-cast concrete beam structure, the equivalent section characteristic parameters of concrete at different ages are determined in order to calculate the strain of the first effect of shrinkage and creep under a certain load step. Calculate the elastic strain of the total shrinkage and creep effect under this load step; Calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under this load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the first effect of shrinkage and creep in subsequent load steps.

2. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 1, characterized in that, The method for determining the equivalent section characteristic parameters of concrete at different ages based on batch-cast concrete beam structures, in order to calculate the strain of the first-order shrinkage and creep effect under a certain load step, includes: The cross-sectional properties of concrete materials of other ages, except for the first age concrete material, are converted to the cross-sectional properties of the first age concrete material to determine the converted cross-sectional property parameters of the concrete of different ages. The shrinkage and creep first-order effect internal force in the batch-cast concrete beam structure is set to 0. Based on the converted section characteristic parameters of concrete at different ages, the shrinkage and creep first-order effect strain under a certain load step is calculated.

3. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 2, characterized in that, The calculation of the shrinkage and creep strain under a certain load step based on the converted section characteristic parameters of concrete at different ages includes: The calculation formula is: ； ； ； in, These are the axial strain and the circumferential strain of the first-order effect of shrinkage creep, respectively. y Axis bending curvature and circumference z Shaft bending curvature; The area and radius of concrete materials at different ages are converted to the area of ​​concrete materials at the first age, respectively. y Axial moment of inertia, about z Moment of inertia of the axis; The first i Area of ​​concrete material at different ages, winding y Shaft static moment, about z Shaft static moment, about y Axial moment of inertia, about z Moment of inertia, product of inertia; n The number of materials at different ages; For the first i The elastic modulus ratio of the first-age concrete material to the first-age concrete material; For the first i The increase in shrinkage strain of concrete materials at a certain age over the calculation period; m To calculate the number of load steps applied before the start of the time period; For the first i Seedling age materials j The creep coefficient increment during the calculation period; The first j The first loading caused the i Elastic axial strain and circumferential strain of concrete materials at different ages y Axis bending curvature and circumference z Axis bending curvature.

4. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 1, characterized in that, The elastic strain used to calculate the total shrinkage and creep effect under this load step includes: The equivalent nodal load of shrinkage and creep effect is obtained based on the strain of the first effect of shrinkage and creep. The equivalent nodal loads of shrinkage and creep in the batch-cast concrete beam structure are aggregated into a total load vector. The strain results of the shrinkage and creep effect are calculated and used as the elastic strain of the total shrinkage and creep effect under the load step.

5. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 4, characterized in that, The equivalent nodal load for shrinkage and creep effect obtained based on the primary effect strain of shrinkage and creep includes: When the beam element in the batch-cast concrete beam structure is a uniform cross-section element, the equivalent nodal load of shrinkage and creep effect is calculated based on the strain of the first-order effect of shrinkage and creep.

6. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 4, characterized in that, The equivalent nodal load for shrinkage and creep effect obtained based on the primary effect strain of shrinkage and creep includes: When the beam elements in the batch-cast concrete beam structure are variable cross-section elements The strain of the first effect of shrinkage and creep inside the beam element is calculated by linear interpolation of the strain of the first effect of shrinkage and creep at the end nodes of the beam element, so as to obtain the relative displacement of the end nodes of the beam element. The equivalent nodal load for shrinkage and creep is calculated based on the relative displacement.

7. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 3, characterized in that, The calculation of the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under this load step includes: Based on the plane section assumption, calculate the first... i Materials at different ages in cross-sectional coordinates ( y,z The formula for calculating the elastic strain of the self-stress at point () is: ； in, ; ; 。 8. The method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in claim 7, characterized in that, The step of using the sum of the elastic strain of the total shrinkage and creep effect and the elastic strain of the self-stress as the elastic strain for calculating the first-order effect of shrinkage and creep in subsequent load steps includes: ； ； ； in, The elastic strain is the total elastic strain due to shrinkage and creep under this load step. This represents the elastic strain due to the primary effect of shrinkage and creep under subsequent load steps.

9. A system for calculating the shrinkage and creep effect of batch-cast concrete beam structures, using the method for calculating the shrinkage and creep effect of batch-cast concrete beam structures as described in any one of claims 1 to 8, characterized in that, It includes: The primary effect strain calculation module is configured to: determine the equivalent section characteristic parameters of concrete at different ages based on the batch-cast concrete beam structure, in order to calculate the primary effect strain of shrinkage and creep under a certain load step; The total effect strain calculation module is configured to calculate the elastic strain of the total shrinkage and creep effect under this load step. The self-stress elastic strain calculation module is configured to: calculate the self-stress elastic strain generated by shrinkage and creep of concrete at different ages under the load step, and use the sum of the self-stress elastic strain and the elastic strain of the total effect of shrinkage and creep as the elastic strain for calculating the first effect of shrinkage and creep in subsequent load steps.

Images