Seismic Damage Behavior Of Square Steel Tube Column Filled With Aeolians And Concrete

There are large areas of deserts in northwestern my country.If aeolian sand is used reasonably,it can not only curb the desertification process,but also reduce the dependence on river sand in actual projects,thereby reducing project costs.Therefore,in order to promote the application of aeolian sand resources in steel tube concrete structures,this paper proposes square steel tube column filled with aeolian and concrete.Through low-cycle repeated load tests and comparative analysis,the seismic damage performance of such specimens is studied,and on this basis,the restoring force model and damage model of the specimens are established;in addition,the finite element simulation software ABAQUS is used to perform finite element analysis on the square steel tube column filled with aeolian and concrete.The main research contents are as follows:1.This paper selects the aeolian sand of the Kubuqi Desert in Inner Mongolia Autonomous Region as the raw material,designs and manufactures 4 square steel tube aeolian sand concrete columns with a scale ratio of 1:2,and carries out a low-cycle repeated load test.,Focus on the main seismic damage indicators of each specimen,including failure mode,hysteretic performance,ductility,stiffness,and cumulative energy consumption.The research results show that: compared with the ordinary aeolian sand concrete column,the specimen FARC has fuller hysteresis,better ductility,higher bearing capacity,and more rigidity degradation.Slow and more energy-consuming,the square steel tube can significantly improve the hysteretic performance,ductility,bearing capacity,stiffness,and energy-dissipation properties of aeolian sand concrete columns.2.Using Origin software and the least square method to fit and analyze the test data,a three-fold line restoring force model suitable for square steel tube column filled with aeolian and concrete was established on the basis of the test.The research results show that the established restoring force theory model is in good agreement with the experimental results,and the correlation is above 0.94,which can provide a basis for the elastoplastic analysis of such square steel tube column filled with aeolian and concrete.3.On the basis of experiments,the measured data is fitted and analyzed,and a dual-parameter damage model based on stiffness and energy consumption is established.At the same time,a theoretical analysis was made on the quantitative indicators of the damage of the square steel tube column filled with aeolian and concrete.The research results show that the revised two-parameter damage model and the quantitative index of damage in this paper are in good agreement with the seismic damage evolution process of the specimen.4.Use the finite element simulation software ABAQUS to perform finite element analysis on the square steel tube column filled with aeolian and concrete,Using ABAQUS finite element simulation software to obtain the characteristic points and skeleton curves of the specimens,the theoretical values are in good agreement with the experimental values,indicating that the established theoretical model can be used for the elastoplastic analysis of square steel tube column filled with aeolian and concrete.By changing the axial compression ratio of the specimen,the strength of aeolian sand concrete and the steel pipe wall thickness and other parameters,the influence of the above parameters on the seismic performance of the square steel tube column filled with aeolian and concrete is analyzed.The results show that:(1)When the axial compression ratio is 0.2～ Within the range of 0.4,the bearing capacity of the square steel tube column filled with aeolian and concrete increases with the increase of the axial compression ratio.When the axial compression ratio is in the range of 0.5-0.6,the bearing capacity of the specimen is not significantly improved,and the ductility is greatly reduced.(2)With the improvement of the strength level of aeolian sand concrete,the characteristic points such as the yield load,peak load and failure displacement of the specimens are slightly increased.(3)The wall thickness of the square steel pipe is in the range of 1-5mm.As the wall thickness of the steel pipe increases,the ultimate bearing capacity and ductility of the test piece have been improved to a certain extent,but when the wall thickness of the square steel pipe reaches 7mm,the seismic performance of the test piece does not increase significantly,indicating that it is appropriate Increasing the wall thickness of the steel pipe within the range is beneficial to improve the seismic performance such as the bearing capacity and ductility of the specimen.