Experimental Study On Axial Compression Capacity Of Welded Thin-walled H-shaped Steel PEC Short Columns

With the continuous promotion and use of the green buildings in the new era,PEC composite structure got more and more attention and the engineering application prospects were also more impressive.Such assembled structures not only have high carrying capacity,good fire resistance and good ductility,but also have good prefabrication performance,which can save formwork and reduce construction waste emissions.However,China’s current research on PEC thin-walled structure is not deep enough and has not yet established a complete relevant specification.Therefore,this paper aims to provide references for the application of such PEC components in actual engineering through test and finite element simulation analysis of thin-walled H-shaped steel PEC short column.In this paper,six thin-walled H-shaped steel PEC short columns were designed and tested for axial compression bearing capacity.The influences of different flange width-to-thickness ratio and concrete strength grade were considered as the test parameters.The deformation characteristics and ultimate bearing capacity of thin-walled H-shaped partially concrete composite short columns were studied.And the effects of concrete strength grade and flange width-to-thickness ratio on the ultimate bearing capacity of the specimen were analyzed.Based on the principle of superposition,the formula for calculating the ultimate bearing capacity of thin-walled H-shaped steel PEC short column was established.The finite element software ABAQUS was used to establish and analyze models,the simulation results were compared with the test results,and further research on the axial compression specimens with different flange width-thickness ratios and different strength concretes were studied.And the limiting value of PEC column flange width and thickness ratio is presented.The results show that the concrete cracks of the thin-walled PEC short column entering the elasto-plastic stage extend and widen gradually.After reaching the maximum bearing capacity,the flanges have a relatively obvious local buckling phenomenon.At the same time,the concrete were detached and thetie bars were broken.When the flange width-to-thickness ratio of the test series increased from 18.4 to 36.8,the ultimate bearing capacity of this kind of specimens decreased by 12.26%～21.35%.When the concrete strength grade increased from C20 to C35,the ultimate bearing capacity of the test series increased by 7.33%～9.64%.It indicates that reducing the width-thickness ratio of the flange and increasing the concrete strength grade can effectively improve the ultimate bearing capacity of PEC short columns.When the steel content increased from 4.613% to 7.227%,the column ductility coefficient increased.It shows that increasing the steel content will strengthen the constraint of the steel on the concrete and improved the column ductility.