The Nonlinear Analysis On The Seismic Performance Of Joints Between Prestressed Steel Reinforced Concrete Beams And Concrete-filled Steel Tubular Core Columns

With the rapid development of national economy and the need of urban construction,super high-rise and long-span buildings have be used in recent years,which promoting the development of steel-concrete composite structures.Prestressed steel-concrete structures can effectively adapt to the trend of modern buildings becoming high-performance and intensive,which promoting the development of modern structures in large span and good seismic performance.But for post-tensioned prestressd steel-concrete frame,the ultimate bearing capacity of the joint is weaken and construction techniques are complicated for complex joint construction.So,in order to solve the problems of joint constructions and construction techniques,joints between prestressed steel reinforced concrete beams and concrete-filled steel tubular core columns are taken as study objects in this paper.Baesd on the results of seismic experiments for joints between prestressed steel reinforced concrete beams and concrete-filled steel tubular core columns,the failure process of the joints and the influence factors of shear bearing capacity are researched by ABAQUS-6.10.First,numerical models for joints between prestressed steel reinforced concrete beams and concrete-filled steel tubular core columns under cyclic and monotonic loading are built by ABAQUS.The displacement-load curves for cyclic and monotonic loading are get in numerical models,which can verify the validity of numerical models by Comparing data of test and simulation.The results show that models built for experiments are reliable in the bearing capacity.Second,the failure mode is analyzed based on the numerical model under cyclic loading and the failure process,concrete damage and steel stress are analyzed based on the numerical model under monotonic loading.Third,parameter analysis and shear capacity calculation are done by calculating hysteretic curves which costing a lot of time based on the numerical model under monotonic loading.Based on the above,four parameters influencing shear capacity are analyzed,including degree of prestress,axial compression ratio,shaped steel ratio and stirrup ratio in the core region.Some results are shown as follows.First,two parameters,degree of prestress and stirrup ratio in the core region,influence a little on shear capacity,but it can reduce shear deformation in the core region.Second,shaped steel ratio makes a large difference in shear capacity,and axial compression ratio littler,but high axial compression ratio can reduce shear deformation in the core region on the failure stage.Third,appropriate thickness of steel tube and diameter of the stirrup in the core region can reduce shear deformation in the core regionFinally,the calculation method about shear capacity of joints between prestressed steel reinforced concrete beams and concrete-filled steel tubular core columns is proposed in this paper.The formula deducted from Finite element simulation and the formula which adjusted to apply in actual projects are verified valid by comparing it with test and relevant specifications.