Experimental Study On The Properties Of Reactive Powder Concrete-Filled Square Steel Tube Columns

The reactive powder concrete is a new kind of high performance concrete with the advantages of ultra-high strength,high durability,high toughness and high modulus of elastic.It is in conformity with the engineering requirements of high strength,small weight,stability and high durability.However,the reactive powder concrete is same with the high-strength concrete,both have brittleness shortcomings,it can effectively improve this shortcoming to place the concrete under certain constraints.In this paper,the reactive powder concrete was poured into the square steel,forming a combined structure of strong and strong combination,which can make up for the lack of their own material performance at the same time,make full use to the advantages.At present,there are few experimental research on the reactive powder concrete columns at home and abroad.The research on the working mechanism and failure mode of the concrete pipe and concrete is not deep enough.Therefore,it is necessary to further study the reactive concrete column.In this paper,we use the combination of experimental and numerical simulation method to study the basic mechanical properties of square steel tubular reactive powder concrete columns under axial compression and eccentric compression.In the test part,21 reactive powder concrete filled square steel tube columns members were analyzed with slenderness ratio,steel content and eccentricity as parameters.The displacement behavior,the load-displacement curve and the load-strain curve under the parameters of different slenderness ratio and different steel content are analyzed.For the bias components,the cross section is assumed to be checked that the neutralization is determined.The test shows that with the increase of steel content,the higher the bearing capacity,the larger the increase of bearing capacity in the later stage of the test.With the increase of eccentricity,the neutral axis position gradually moves towards the compression side.By analyzing and comparing five existing calculation formulas of common concrete-filled steel tubular structures,it is concluded that the technical specification for concrete-filled steel tubular structures GB 50936-2014 is more suitable for calculating the bearing capacity of axially compressed members,and CECS 28: 2012 is more suitable for calculating the bearing capacity of eccentrically compressed members.On the basis of experimental research,the nonlinear finite element software ABAQUS is used to simulate and study the reactive powder concrete filled steel tube column.considering the actual situation of the interaction interface between steel tube and concrete,the axial thrust test is designed to get the load-slip curve of the interface between steel tube and concrete,and the test results are applied to theoretical analysis.Comparing and analyzing the failure modes and load-displacement curves of simulated and tested components,the two parameters are in good agreement,which verifies the reliability of the thrust test results.the results of load-slip curve can be used as the numerical basis for extended research.