内置十字型钢高强混凝土巨型圆柱的抗震性能

Seismic Performance of Encased Cross-section Steel Reinforced High-strength Concrete Circular Column

为研究含钢率对其抗震性能的影响,对2个大尺寸内置十字型钢高强混凝土圆柱进行低周反复荷载试验.分析破坏特征、滞回曲线、承载力、变形、刚度退化过程及耗能,并采用ABAQUS软件对试件抗震性能进行有限元模拟,分析轴压比、混凝土强度、配筋率、翼缘厚度和加载方向等参数对试件抗震性能的影响.结果表明:2个试件的破坏以弯曲为主,滞回曲线饱满,承载力下降缓慢;提高含钢率,试件承载力增大,刚度退化较慢,抗震性能好.提高轴压比和混凝土强度,峰值位移变小,峰值荷载提高,峰值荷载后,承载力衰减变快,延性较差;提高配筋率和改变加载方向,峰值荷载提高不明显,峰值荷载后,承载力衰减速度相似,对延性影响不大;提高十字型钢翼缘厚度,峰值荷载和延性提高,表现出更好的抗震性能.本文研究可为内置十字型钢高强混凝土圆柱的工程应用提供参考.

SRC columns are widely used in high-rise buildings because of their good seismic performance.To investigate the influence of steel ratio on its seismic performance,low-cyclic loading test was conducted on two big sized encased cross-section steel reinforced high-strength concrete circular columns.The failure characteristics,hysteresis curves,bearing capacity,deformation,stiffness degradation process and energy dissipation of the two specimens were analyzed.ABAQUS software was used to simulate the seismic performance of the specimens,and the influence of parameters such as axial compression ratio,concrete strength,reinforcement ratio,flange thickness and loading direction on the seismic performance of the specimen was analyzed.Results show that the failure of the two specimens is mainly bending,the hysteresis curves are full and the bearing capacity decreases slowly.With the increase of the steel ratio,the bearing capacity increases,stiffness degrades slowly,and seismic performance is good.With the increase of the axial compression ratio and concrete strength,the peak displacement gets smaller and the peak load increases.After the peak load,the bearing capacity decreases quickly and the ductility is poor.When the reinforcement ratio increases and the loading direction is changed,the increase of peak load is not obvious.After the peak load,the decay rate of bearing capacity remains unchanged,which has little impact on ductility.By increasing the thickness of the cross-section steel flange,the peak load and ductility are improved,and the seismic performance is better.This study provides a reference for the engineering application of the encased cross-section steel reinforced high-strength concrete circular column.