Experimental Study On Seismic Behavior Of Square Steel Tube Reactive Powder Concrete Columns

As a new type of high-performance cement matrix composite material,reactive powder concrete(RPC)has high strength,good durability,good toughness and volume stability.However,its disadvantages include high brittleness and poor crack resistance.It is combined with square steel tube to form RPC square steel tube,which can give full play to the advantages of the two.At present,the research on the seismic performance of RPC steel tube mainly focuses on the compressive performance.However,the experimental data are relatively few,and the research is mainly confined to theoretical analysis.Therefore,the seismic performance research of RPC steel tube is of great engineering significance.In this paper,four square steel tube RPC column specimens were designed,and the influence parameters of axial compression ratio and steel rate were considered respectively.Under a certain axial compression ratio,the specimens were tested under low cyclic loading.Through the analysis of the test phenomena and results,the influence of different factors on the seismic performance of RPC column was discussed.Through the RPC filled steel tube column P-? hysteresis curve,found of hysteresis curve are full,smooth all party RPC filled steel tube column has good energy dissipation capacity.Through the skeleton curves and stiffness degradation curves of each column,it was found that the skeleton curves of each specimen decreased slowly at the later stage of loading,which showed that the reactive powder concrete column of square steel tube had good plastic deformation capacity.Before yielding,the stiffness is basically kept in a straight line without major degradation.After yielding,with the increase of displacement and cycle times,it can be seen that the strength of each specimen decreases continuously,and the downward trend is gradually gentle,until the specimen is destroyed.The mechanical properties were analyzed and studied by the finite element software ABAQUS.The parameters such as axial pressure ratio,steel-bearing ratio,friction coefficient and yield strength were changed to simulate 9 RPC columns of square steel tubes.The hysteresis curves of steel tubes with different parameters were obtained by the finite element software analysis.Will test results of the calculated results with the corresponding parameters of hysteretic curves are analyzed,and the resulting P-? hysteresis curve has good match compared with experiment.The main factors affecting the load-displacement relationship of RPC column were analyzed,and the skeleton curves of each specimen under different parameters were analyzed and compared,so as to obtain the influence law of each parameter on its seismic performance,which provided a basis for the seismic design of RPC column.