银川绿地中心型钢混凝土梁柱节点性能非线性分析

Nonlinear Performance Analysis of Steel Reinforced Concrete Beam Column Joints in Yinchuan Green Space Center

型钢混凝土结构具有承载力高、抗震性能好和裂缝可控制等优点,近年来在建筑结构中已经得到了广泛的研究和应用,但型钢混凝土现阶段存在钢筋可能贯穿内型钢,削弱型钢承载力的问题,同时造成施工过程中工艺复杂。银川绿地中心作为宁夏回族自治区的第一高楼,工程中两座塔楼均采用框架-核心筒混合结构体系,外框架由H型钢梁和型钢混凝土柱构成,在型钢混凝土梁柱节点处有大量箍筋需要穿透型钢,造成施工困难。根据工程实际情况,提出了一种新型箍筋加强型节点的构造方法,以解决施工存在问题。针对此背景,基于两种型钢混凝土梁柱节点试验,应用ABAQUS平台建立了箍筋穿透型节点和箍筋加强型节点的柱节点模型,在试验验证数值模型的基础上,深入分析箍筋加强型节点构造措施的可行性,考察了改进构造措施和原构造措施的承载力差别。为探究不同设计参数对改进构造措施的承载性能影响,以箍筋加强型节点试件数值模型为基准进行参数分析,考察了轴压比、型钢含钢率、柱中纵筋配筋率对箍筋加强型节点的骨架曲线的影响。结果表明:所建立的数值模型可以良好模拟节点构件在恒定轴压和水平低周往复位移作用下的承载力峰值、骨架曲线和破坏模式;所模拟的两种节点构造的变形能力、破坏特征与极限承载力基本相同,与试验现象一致,说明箍筋加强型能够满足结构承载力和破坏模式的要求,在施工困难的部位可采用箍筋加强型节点替代箍筋穿透型节点。参数分析结果表明:随着轴压比增大,骨架曲线的峰值荷载不变,节点试验延性逐渐降低;随着型钢混凝土含钢率的增加,构件承载力有一定幅度的提高,但研究范围的配钢率对改进工法构件延性影响很小;主筋配筋率对箍筋加强型节点的骨架曲线的影响较大,随主筋配筋率增加,峰值承载力显著增大。

Steel reinforced concrete structure has many advantages,such as high bearing capacity,good ductility in earthquake and controllable cracks.In recent years,it has been widely studied and applied in building structures.However,traditional steel reinforced concrete has the defects that reinforcement will weaken the bearing capacity of the steel during to penetrating the inner steel,and make the process of construction complex.As the tallest building in Ningxia Hui Autonomous Region,Yinchuan Greenland Center adopts steel reinforced concrete structure.A large number of stirrups need to penetrate the section steel at the beam column joints,which increases the processing capacity of the steel structure.A construction method of reinforcement without penetrating stirrup is proposed to solve the problem in construction according to the actural situation of the project.In view of this background,two kinds of steel reinforced concrete beam column joints model based on the completed tests was analyzed by using ABAQUS platform.On the basis of experimental verification of the numerical model,the feasibility of stirrup reinforced joint construction measures was analyzed,and the bearing capacity difference between the improved process and the prototypical process was investigated.In order to explore the influence of different design parameters on the bearing capacity of improved process,this paper analyzed the influence of parameters based on the numerical model of stirrup reinforced joint specimens,and investigated the influence of axial compression ratio,steel content of section steel,and reinforcement ratio of longitudinal reinforcement in column on the skeleton curve of stirrup reinforced joint.The results show that the numerical model can properly simulate the peak bearing capacity,skeleton curve and failure mode of specimens under constant axial pressure and horizontal displacement.The deformation capacity,failure mode and ultimate bearing capacity of the two processes are basically the same,which is consistent with the experimental phenomenon,indicating that the stirrup reinforced type can meet the requirements of structural bearing capacity and failure mode.The improved process therefore can be used to replace prototypical process where the process is complicated.The results of parameter analysis show that with the increase of axial compression ratio,the peak load of skeleton curve remains unchanged,and the ductility of joint test decreases gradually.With the increase of steel ratio of steel reinforced concrete,the bearing capacity of members has a certain range of improvement,and the steel ratio has little effect on the ductility of members with improved construction method.The ratio of main reinforcement has a great influence on the skeleton curve of stirrup reinforced joints,and the peak bearing capacity increases significantly with the increase of the ratio of main reinforcement.