Direct Analysis Method Of Steel Braced Frame Structure Based On Overall Structural Displacement Control

Most of the direct analysis methods applicable at this stage are based on the structural ultimate bearing capacity.For high flexible steel frame structures that are greatly affected by deformation performance,the horizontal displacement of the column top of the structure under its ultimate bearing capacity often exceeds the limit required by the code It is necessary to redesign the size of its components and then check the stability and deformation of the structural beams and columns.Repeat the design until the determined component size meets the requirements of the structure under the condition of the ultimate bearing capacity.Therefore,a direct analysis method based on the overall displacement control of the structure is proposed,and there are few such studies on the direct analysis method of structural deformation performance at home and abroad.In view of the above,this article mainly performs the following tasks:The low-cycle reciprocating load test was performed on a two-span,six-story steel frame and a steel frame-support specimen with a height of 4.5 meters and a span of 1.5 meters.The test passed three MTS at a ratio of 3:2:1 through the sixth,fourth,and second layers of the test specimen to apply a horizontal load to the test specimen.The entire process of the test used displacement control.The hysteresis curve of the structure and the related hysteresis performance are obtained through tests.At the same time,it is found that the maximum horizontal displacement of the structure during the test has far exceeded the limit required by the specification.ANSYS finite element software simulation was used to directly analyze the entire process of the low-cycle reciprocating test of the two-span and six-story steel frame and the steel braced frame structure.The beam and column selected the Beam 188 element and the support selected the Link 10 element.The constitutive relationship is based on the material property test data,and the actual initial geometric defects of the structural members are considered in the simulation.The finite element simulation results were compared with the test results mainly from the final failure shape,hysteresis curve,skeleton curve,ductility,stiffness degradation,and energy consumption.It was found that the simulation results were in good agreement with the test results.The correctness of the finite element model of this kind of problem.ANSYS finite element software was used to simulate the whole process of the low-cycle reciprocating tests of the steel frame and the steel frame-support structure,and the actual initial geometric defects of the structural members measured before the test were fed back into the model.Compared with the test results in terms of failure morphology,hysteresis curve,skeleton curve,ductility,stiffness degradation,and energy consumption of the two specimens.The results show that the finite element simulation results are in good agreement with the experimental results,which verifies the correctness of the finite element modeling for analyzing such problems.The finite element model proposed in this paper analyzes the hysteretic performance of the steel frame-support structure with different parameters under low-cycle reciprocating load tests,and studies the relationship between the maximum horizontal displacement that can be achieved at the top of the column and the specification limit.A study on the relationship between the limit displacement of the structure and the specification limit under the monotonic load of the steel frame-support structure,found that the bearing capacity of the high-rise steel frame-support structure is affected by the deformation performance,so a direct analysis method based on the overall displacement control of the structure is proposed.When the current direct analysis method based on the ultimate bearing capacity of the structure is adopted for the highrise steel frame-support structure,the horizontal displacement of the column top under the state of the ultimate bearing capacity of the structure exceeds the specification limit,it is necessary to continuously adjust the size of the component or reduce the bearing capacity,and the design process is cumbersome..When the direct analysis method based on the overall displacement control of the structure is used,the horizontal displacement of the column top in its normal use state is first calculated according to the predetermined size of the structural member.If the deformation meets the requirements of the code,the load of the structure under the allowable load factor is checked.Force can generally meet the requirements,which makes the design process simple and achieves the same results as the limit state design method.When determining the applicable range of the direct analysis method based on deformation control,a’ simple estimation of the overall displacement of the structure is needed first.Three methods can be proposed for the structural columns through the calculation of the fitting formula calculation,neural network prediction,and finite element analysis.The top horizontal displacement is simply estimated.When the estimated lateral displacement of the column top exceeds the limit required by the code,it is more appropriate to use the direct analysis method based on the overall displacement control of the structure to design the structure,otherwise the direct analysis method based on the ultimate bearing capacity of the structure may be used.