Study On Mechanical Behavior Of Insulated Sandwich Concrete Wall With Embedded Columns

Insulated sandwich concrete wall has the advantages of good thermal insulation performance,low cost,bearing and retaining functions,and has attracted wide attention.In this paper,on the basis of traditional insulated sandwich concrete wall,adding cold-formed thin-walled steel embedded columns,horizontal distribution bar and tie bar,an insulated sandwich concrete wall with embedded columns(ISCW-EC)is proposed.Considering the different spacings of horizontal bar,axial compression tests were carried out on two full-scale specimens,eccentric compression tests were carried out on two full-scale specimens,and low cyclic loading tests were carried out on two┃-shaped full-scale specimens and two L-shaped full-scale specimens.The test results show that under axial compression,local buckling occurs in the embedded column,and splitting failure occurs in the concrete.When the horizontal bar spacing is small,the cracking load is small and the ultimate bearing capacity is large.Under eccentric compression,with the load increases the concrete cracks at the side away from the point of application of the eccentric load,while the depth of the concrete compression zone decreases at the side near the point of application.Ultimately,the concrete in the compression zone is crushed thus the failure of ISCW-EC under eccentric load is brittle.When the horizontal reinforcement spacing is small,the cracking load is large.Under the low cyclic loading,the final failure modes of the wall all show local buckling failure of the embedded column and serious loss of concrete at the corner.But the┃-shaped wall presents the bending shear failure mainly by bending and L-shaped wall presents bending-shear failure mainly by shear.In terms of mechanical properties,for the┃-shaped wall and L-shaped wall,when the intense arrangement of the horizontal reinforcement,it presents the brittle failure characteristics of super reinforcement and fails to effectively play the mechanical properties of materials.However,the shear capacity,ductility,and energy dissipation capacity are significantly improved when the horizontal reinforcement spacing is large.A comparative study with experiments,one hundred and twenty-one finite element models were established.Specifically,Thirty-five refined finite element models were established to perform the multi-parameter analysis in which the influences of horizontal reinforcement spacing,embedded columns spacing,concrete strength and steel wire gauge on the axial compression bearing capacity of ISCW-EC are evaluated.The finite element results show that the axial compression bearing capacity increases with the increase of concrete strength and steel wire diameter,and decreases with the increase of horizontal bar spacing and embedded column spacing.Forty-seven refined finite element models were established to perform the multi-parameter analysis in which the influences of horizontal reinforcement spacing,embedded column spacing,concrete strength,eccentricity and steel wire gauge on the eccentric compression bearing capacity of ISCW-EC are evaluated.The results show that the horizontal reinforcement spacing has little influence on the load bearing capacity.The load bearing capacity increases with the increases of concrete strength or steel wire gauge,while the capacity decreases with the increases of eccentricity or embedded column spacing.Thirty-nine refined finite element models were established to perform the multi-parameter analysis in which the influences of horizontal reinforcement spacing,axial compression ratio,concrete strength and steel wire gauge on shear bearing capacity of ISCW-EC are evaluated.The finite element results show that the shear capacity increases with the increase of concrete strength,steel wire diameter and axial compression ratio,and decreases with the increase of horizontal bar spacing.Finally,based on the test results and finite element results,referring to the existing standard,the calculation formulas of axial compression bearing capacity,eccentric compression bearing capacity and shear bearing capacity are proposed.The calculation results are in good agreement with the test and finite element analysis results.