| The five-spiral stirrups steel reinforced concrete structure is a new type of stirrup configurations,in which the ordinary stirrups are replaced by five groups of spiral stirrups,four small spiral stirrups are located at the four corners of the rectangular concrete column,and a large spiral stirrup displaces the center of the rectangular concrete column to assist the steel to restrain the concrete in the core area.The center of the large stirrup has steel to improve the bearing capacity of the column,and the circular spiral stirrups can increase the deformation capacity of the concrete column.The mechanical properties are better when using the same material.This paper mainly carries out the numerical simulation analysis of the axial compression performance and hysteretic performance of five stirrup SRC columns,and puts forward the calculation formula for the axial compression bearing capacity of five stirrup SRC columns,the main research contents are as follows:（1）In order to more accurately simulate the different restraint effects of stirrup and section steel on concrete,the column section concrete is divided into strong restraint concrete,weak restraint concrete and unconstrained concrete.The mechanical characteristics of different restraint concrete are analyzed,and the constitutive models of stirrup restraint concrete and section steel restraint concrete are proposed,and the corresponding finite element analysis models are established.（2）The axial pressure analysis of five-spiral stirrups steel reinforced concrete column is carried out in ABAQUS finite element software.Compared with the existing test results,the error of axial bearing capacity is within 6%,the load displacement curves are close and the failure characteristics are similar.The analysis model established by constitutive model of concrete in different zones is reliable and can simulate the bearing capacity of the column accurately.Three groups of comparison groups were established by using the verified model.The parameters of the ratio of volume stirrup,steel distribution rate and the ratio of the cross-section area of the large and small stirrups were analyzed respectively.The results showed that the increase of the size of the section steel had the greatest influence on the bearing capacity and the greatest influence of changing the stirrup spacing on the ductility coefficient.（3）According to the stress nephogram distribution of finite element analysis,based on Mander model,the calculation methods of axial bearing capacity of strong restraint concrete and weak restraint concrete are modified.The superposition principle is used to derive the calculation formula of axial bearing capacity of five-spiral stirrups steel reinforced concrete column.Compared with the test results and finite element simulation results,the error is stable within 10%,and the calculation method is simple.The results are reliable.（4）Using ABAQUS finite element software,the hysteretic behavior of a series of five-spiral stirrup SRC columns and five-hoop stirrup SRC columns,rectangular-spiral stirrup SRC columns and normal rectangular stirrup SRC columns with the same steel consumption are studied.The hysteretic curve,skeleton curve,stiffness degradation curve and seismic energy consumption of each component are compared to evaluate the seismic performance of five-spiral stirrup SRC columns.The results show that increasing the amount of longitudinal reinforcement and stirrup and improving the strength of concrete can improve the hysteretic behavior of five stirrup SRC columns,and the seismic performance of the five stirrup SRC columns studied in this paper is good.The peak load,ductility coefficient and seismic energy consumption of the SRC column with five stirrups are 1.14 times,1.87 times and 3.08 times respectively,which are 1.14 times,1.87 times and 1.87 times respectively.The seismic performance of the SRC column with five-spiral stirrups is the best with the same amount of reinforcement.The results show that the SRC column with five-spiral stirrups has good mechanical performance in all aspects,and has good denaturation ability,so it is a better stirrup scheme in engineering design. |
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