CN-122021290-A - Buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization

CN122021290ACN 122021290 ACN122021290 ACN 122021290ACN-122021290-A

Abstract

The invention relates to the field of structural engineering earthquake-resistant design, in particular to a buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization, which comprises the steps of establishing a parameterized analysis model taking horizontal sharing rate beta as a variable, carrying out elastoplastic power time course analysis, extracting whole process response data, and further calculating an instantaneous equivalent horizontal sharing rate beta (t) representing dynamic evolution of internal force distribution and a stability index thereof, finally taking the stability index and at least one other performance index together as an optimization target, carrying out multi-target optimization solution on beta to obtain a horizontal sharing rate design value with optimal robustness, and completing the cross section design of the component according to the horizontal sharing rate beta (t). The method realizes quantitative evaluation and active optimization of the stability of the force distribution path of the structure in the whole period under the earthquake action, and improves the earthquake-proof robustness, the cooperative energy consumption efficiency and the comprehensive economy of the buckling restrained brace steel frame.

Inventors

YUAN WENKE
MA SHIYI
BAO ENHE

Assignees

贵州大学

Dates

Publication Date: 20260512
Application Date: 20260127

Claims (10)

1. The buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization is characterized by comprising the following steps of: S1, establishing a parameterized analysis model of a buckling restrained brace steel frame, and taking the horizontal sharing rate in the parameterized analysis model as a core design variable, wherein the horizontal sharing rate is the proportion of the horizontal shearing force born by the brace in the total floor shearing force; s2, selecting at least one earthquake motion record as an input load; S3, performing elastoplastic dynamic time-course analysis on the parameterized analysis model to obtain overall process response data of the parameterized analysis model under the action of the earthquake motion record; S4, calculating the instantaneous equivalent horizontal sharing rate of the parameterized analysis model, which changes with time during the earthquake motion recording action period, based on the whole process response data, wherein the instantaneous equivalent horizontal sharing rate is a function of time; S5, calculating a stability index for quantifying the fluctuation level of the curve according to the curve of the instantaneous equivalent level sharing rate changing along with time; S6, the stability index and at least one other structural performance index are used as optimization targets together, and the horizontal sharing rate is optimized and solved, so that a horizontal sharing rate design value with optimal robustness is obtained; And S7, adopting the horizontal sharing rate design value with optimal robustness to carry out cross section design of the buckling restrained brace and the frame member, and generating a final structural design scheme.
2. The method for earthquake-resistant design of the buckling restrained brace steel frame based on horizontal sharing rate optimization according to claim 1, wherein the calculating of the instantaneous equivalent horizontal sharing rate in step S4 specifically comprises: S41, extracting interlayer total shear data of each floor and shear data shared by buckling restrained braces in each floor according to each calculation time point from the whole process response data; S42, calculating the instantaneous floor horizontal sharing rate of each floor at each time point according to the interlayer total shear data of each floor and the shear data shared by the buckling restrained brace; S43, carrying out weighted average operation on the instantaneous floor level sharing rate of each floor at each time point to obtain the instantaneous equivalent level sharing rate corresponding to the time point.
3. The method for earthquake-resistant design of buckling restrained brace steel frame based on horizontal sharing optimization according to claim 2, wherein in step S43, the weight coefficient used in the weighted average operation is the absolute value of the total interlayer shear data corresponding to each floor.
4. The method for earthquake-proof design of a buckling restrained brace steel frame based on horizontal sharing rate optimization according to claim 1, wherein in step S5, the stability index is a standard deviation or variance of the curve of the instantaneous equivalent horizontal sharing rate over time in the whole earthquake motion record duration.
5. The method for earthquake-resistant design of buckling restrained brace steel frames based on horizontal sharing optimization as set forth in claim 1, wherein in step S6, the at least one other structural performance index comprises any one or more of a maximum interlayer displacement angle of the parameterized analytical model, a total material consumption of the parameterized analytical model, and a substrate shear force when the parameterized analytical model reaches a preset interlayer displacement angle limit.
6. The buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization according to claim 1 is characterized in that in step S6, optimization solution is carried out on the horizontal sharing rate specifically, a multi-objective optimization algorithm is adopted, the horizontal sharing rate is used as an optimization variable, and iterative search calculation is carried out with the aim of simultaneously minimizing the stability index and the at least one other structural performance index.
7. The buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization according to claim 6, wherein the multi-objective optimization algorithm is a genetic algorithm, a particle swarm optimization algorithm or a multi-objective genetic algorithm.
8. The method for designing the buckling restrained brace steel frame earthquake-resistant based on the horizontal sharing rate optimization of claim 1 is characterized in that in the step S2, at least one earthquake motion record is selected, wherein at least three earthquake motion records with different frequency spectrum characteristics are selected; in step S5, the stability index is an average value of a plurality of stability indexes calculated for each seismic record.
9. The method for designing the buckling restrained brace steel frame earthquake-resistant based on horizontal sharing rate optimization of claim 1 is characterized in that in the step S1, a parameterized analysis model of the buckling restrained brace steel frame is specifically built, wherein the parameterized analysis model can take material nonlinearity and geometric nonlinearity into consideration, and beams, columns and buckling restrained brace members in the parameterized analysis model are all made of elastic plastic materials.
10. The method for designing the buckling restrained brace steel frame earthquake-resistant based on the horizontal sharing rate optimization of claim 1 is characterized in that in step S6, the method for obtaining the horizontal sharing rate design value with optimal robustness is characterized in that a solution set comprising a plurality of non-inferior solutions is generated in the optimization solving process, solutions with the corresponding stability indexes lower than a preset stability threshold value are selected from the solution set, and the horizontal sharing rate corresponding to the solutions is the horizontal sharing rate design value with optimal robustness.

Description

Buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization Technical Field The invention belongs to the technical field of structural engineering earthquake-resistant design, and particularly relates to a buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization. Background The buckling restrained brace steel frame is subjected to yielding and energy consumption through the initial support, so that the anti-seismic performance of the steel structure is remarkably improved. In this structural system, the horizontal sharing rate β (i.e. the ratio of the horizontal shear force borne by the support to the total shear force of the floor) is a core design parameter that controls the stiffness and bearing capacity distribution relationship between the support and the frame, directly affecting the yield mechanism, deformability, and energy consumption efficiency of the structure. The conventional buckling restrained brace steel frame anti-seismic design method is generally based on the result of elastoplastic static thrust coverage analysis or dynamic time course analysis, and takes a certain limit state response (such as a maximum interlayer displacement angle) or a certain performance point (such as a component yield sequence) of a structure under specific load distribution or earthquake input as an evaluation index, so that the beta value is optimized. Such methods are essentially optimized based on "static performance snapshots" of the structure at a certain time or state. However, under truly strong shock, the structure will experience an overall process of power from elastic to nonlinear, damage-sustained accumulation. With the generation and development of plastic hinges and the degradation of the rigidity of the component, the overall dynamic characteristics of the structure (such as rigidity distribution and self-vibration period) and the internal force distribution relationship between the support and the frame are in continuous dynamic evolution. This effect of "cycle drift" and "stiffness redistribution" due to damage accumulation means that the internal force path and energy dissipation mechanisms of the structure are highly time-varying in the time domain. Therefore, the core limitation of the existing design method is that the quantitative index of the stability of the internal force redistribution path of the structure in the whole earthquake process and the corresponding design framework are lacked. This results in an inability to ensure that the support and frame system remains consistent and stable throughout the continuous dynamic load, but may only perform well at peak response times, but in other periods the energy consumption efficiency fluctuates dramatically due to internal force imbalance. Finally, the horizontal sharing rate beta value determined according to the existing method is difficult to ensure the anti-seismic robustness of the structure in the real seismic sequence. Disclosure of Invention The invention provides a buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization for solving the technical problems. The technical scheme adopted by the invention is as follows: the buckling restrained brace steel frame earthquake-resistant design method based on horizontal sharing rate optimization comprises the following steps: S1, establishing a parameterized analysis model of a buckling restrained brace steel frame, and taking the horizontal sharing rate in the parameterized analysis model as a core design variable, wherein the horizontal sharing rate is the proportion of the horizontal shearing force born by the brace in the total floor shearing force; s2, selecting at least one earthquake motion record as an input load; S3, performing elastoplastic dynamic time-course analysis on the parameterized analysis model to obtain overall process response data of the parameterized analysis model under the action of the earthquake motion record; S4, calculating the instantaneous equivalent horizontal sharing rate of the parameterized analysis model, which changes with time during the earthquake motion recording action period, based on the whole process response data, wherein the instantaneous equivalent horizontal sharing rate is a function of time; S5, calculating a stability index for quantifying the fluctuation level of the curve according to the curve of the instantaneous equivalent level sharing rate changing along with time; S6, the stability index and at least one other structural performance index are used as optimization targets together, and the horizontal sharing rate is optimized and solved, so that a horizontal sharing rate design value with optimal robustness is obtained; And S7, adopting the horizontal sharing rate design value with optimal robustness to carry out cross section design of the buckling re