Experimental Study On Seismic Performance Of Partial Prefabricated Steel Reinforced Concrete Short Columns

The partial prefabricated assembly steel reinforced concrete(PPSRC)structure is a new type of composite structure which combines the partial prefabricated assembly concepts with the steel reinforced concrete structures.The main idea of PPSRC is‘partial prefabrication,partial cast-in-place’,that is,the production of component shell parts in the prefabrication factory,and pouring the rest of the core area as soon as the prefabricated part met the specification requirements of strength and transported to the construction site for assembly.At present,there are few studies on seismic performance of PPSRC short columns at home and abroad,which greatly restricts its application and popularization.Therefore,combined with experimental research and theoretical analysis,this paper mainly carries out the following research on its seismic performance.Firstly,the seismic performance of PPSRC short columns and HPSRC(Hollow Prefabricated Steel Reinforced Concrete)short columns are studied under low cycle reserved loading test.According to the study of failure phenomena,failure modes,hysteretic curve,skeleton curve,stiffness degradation,deformation and energy dissipation capacity of the specimens,the effects of section shape,axial compression,ratios of longitudinal and transverse reinforcement and concrete strength of the inner part were critically investigated.The test results show that the failure modes of the test specimens could be divided into two typical types,namely,the flexural-shear failure mode and the shear failure mode.The specimens with lower longitudinal reinforcement ratios failed in flexural-shear failure,and the rest of the specimens failed in typical shear failure.During the test process,no obvious bonding cracks were found in any test specimens,indicating that the precast RPC,steel shape and cast-in-place concrete bonded well and no obvious concrete spalling were observed.In general,the PPSRC short columns show better energy dissipation and deformation ability than the HPSRC short columns.When the other parameters were the same,a higher stirrup ratio and lower axial compression led to a more satisfactory energy dissipation capacity,stiffness degradation and higher displacement ductility,and the load-bearing capacity increased with increasing inner concrete strength,stirrup ratio and axial compression.Secondly,based on the experimental results and current specifications,the calculation method of shear bearing capacity of PPSRC short column and HPSRC short column are proposed.The calculation results are in good agreement with the test results to verify the accuracy and applicability of the formula proposed in this paper.Finally,by using the combination of theoretical analysis and experimental research,the restoring force model of PPSRC short column is studied,and the calculation method of each characteristic point parameter of skeleton curve is put forward,and the model of degradation restoring force based on trifold line is established.The calculation skeleton curve and test skeleton curve are in good agreement,which shows the accuracy and applicability of the calculation method proposed in this paper.