The axial bearing capacity of prefabricated composite walls composed of inner and outer concrete wythes,expandable polystyrene(EPS)boards and steel sleeve connectors is investigated.An experimental study on the axial ...The axial bearing capacity of prefabricated composite walls composed of inner and outer concrete wythes,expandable polystyrene(EPS)boards and steel sleeve connectors is investigated.An experimental study on the axial bearing capacity of four prefabricated composite walls after fire treatment is carried out.Two of the prefabricated composite walls are normal-temperature specimens,and the others are treated with fire.The damage modes and crack development are observed,and the axial bearing capacity,lateral deformation of the specimens,and the concrete and reinforcing bar strain are tested.The results show that the ultimate bearing capacity of specimens after a fire is less than that of normal-temperature specimens;when the insulation board thicknesses are 40 mm and 60 mm,the decrease amplitudes are 20.8%and 16.8%,respectively.The maximum lateral deformation of specimens after a fire is greater than that of normal-temperature specimens,and under the same level of load,the lateral deformation increases as the insulation board thickness increases.Moreover,the strain values of the concrete and reinforcing bars of specimens after a fire are greater than those of normal-temperature specimens,and the strain values increase as the thickness of insulation board increases.展开更多
The concrete-filled corrugated steel tubular(CFCST)column is a novel steel-concrete composite column characterized by transverse corrugated steel plates.This unique application of the plates leverages their considerab...The concrete-filled corrugated steel tubular(CFCST)column is a novel steel-concrete composite column characterized by transverse corrugated steel plates.This unique application of the plates leverages their considerable out-of-plane stiffness,markedly enhancing the compression performance of CFCST columns while significantly reducing steel material consumption.However,the exact confinement mechanism of the corrugated steel on the infilled concrete remains unclear.To address this question,we analyzed the confinement effect of the CFCST columns under axial compression.The lateral displacement,lateral stress,and bending moment distributions were determined through differential equations,and parametric analysis was performed to examine the impact of varying corrugated steel plate dimensions and concrete strength on these distributions.The results indicated strong confinement effects at the boundary positions,while virtually no effect at the mid-span.The stiffness of the corrugated steel plates and the confinement effect were found to be directly proportional.Additionally,a relationship was established between the average lateral stress of the concrete and the effective confinement coefficient of the CFCST through data fitting,leading to a design formula for calculating the axial compression capacity of CFCST columns.Finally,the accuracy of the formula and its applicability in engineering design were confirmed through validation on experimental data,with the maximum deviation being within±5%.展开更多
To research the axial compression behavior of steel reinforced recycled concrete(SRRC)short columns confined by carbon fiber reinforced plastics(CFRP)strips,nine scaled specimens of SRRC short columns were fabricated ...To research the axial compression behavior of steel reinforced recycled concrete(SRRC)short columns confined by carbon fiber reinforced plastics(CFRP)strips,nine scaled specimens of SRRC short columns were fabricated and tested under axial compression loading.Subsequently,the failure process and failure modes were observed,and load-displacement curves as well as the strain of various materials were analyzed.The effects on the substitution percentage of recycled coarse aggregate(RCA),width of CFRP strips,spacing of CFRP strips and strength of recycled aggregate concrete(RAC)on the axial compression properties of columns were also analyzed in the experimental investigation.Furthermore,the finite element model of columns which can consider the adverse influence of RCA and the constraint effect of CFRP strips was founded by ABAQUS software and the nonlinear parameter analysis of columns was also implemented in this study.The results show that the first to reach the yield state was the profile steel in the columns,then the longitudinal rebars and stirrups yielded successively,and finally RAC was crushed as well as the CFRP strips was also broken.The replacement rate of RCA has little effect on the columns,and with the substitution rate of RCA from 0 to 100%,the bearing capacity of columns decreased by only 4.8%.Increasing the CFRP strips width or decreasing the CFRP strips spacing could enhance the axial bearing capacity of columns,the maximum increase was 10.5%or 11.4%,and the ductility of columns was significantly enhanced.Obviously,CFRP strips are conducive to enhance the axial bearing capacity and deformation capacity of columns.On this basis,considering the restraint effect of CFRP strips and the adverse effects of RCA,the revised formulas for calculating the axial bearing capacity of SRRC short columns confined by CFRP strips were proposed.展开更多
基金The National Key Research and Development Program of China(No.2016YFC0701703)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(No.2016TM045J)the Scientific Innovation Research of Graduate Students in Jiangsu Province(No.KYLX_0151)
文摘The axial bearing capacity of prefabricated composite walls composed of inner and outer concrete wythes,expandable polystyrene(EPS)boards and steel sleeve connectors is investigated.An experimental study on the axial bearing capacity of four prefabricated composite walls after fire treatment is carried out.Two of the prefabricated composite walls are normal-temperature specimens,and the others are treated with fire.The damage modes and crack development are observed,and the axial bearing capacity,lateral deformation of the specimens,and the concrete and reinforcing bar strain are tested.The results show that the ultimate bearing capacity of specimens after a fire is less than that of normal-temperature specimens;when the insulation board thicknesses are 40 mm and 60 mm,the decrease amplitudes are 20.8%and 16.8%,respectively.The maximum lateral deformation of specimens after a fire is greater than that of normal-temperature specimens,and under the same level of load,the lateral deformation increases as the insulation board thickness increases.Moreover,the strain values of the concrete and reinforcing bars of specimens after a fire are greater than those of normal-temperature specimens,and the strain values increase as the thickness of insulation board increases.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(No.LR24E080002)the National Natural Science Foundation of China(Nos.52522803 and 52478219).
文摘The concrete-filled corrugated steel tubular(CFCST)column is a novel steel-concrete composite column characterized by transverse corrugated steel plates.This unique application of the plates leverages their considerable out-of-plane stiffness,markedly enhancing the compression performance of CFCST columns while significantly reducing steel material consumption.However,the exact confinement mechanism of the corrugated steel on the infilled concrete remains unclear.To address this question,we analyzed the confinement effect of the CFCST columns under axial compression.The lateral displacement,lateral stress,and bending moment distributions were determined through differential equations,and parametric analysis was performed to examine the impact of varying corrugated steel plate dimensions and concrete strength on these distributions.The results indicated strong confinement effects at the boundary positions,while virtually no effect at the mid-span.The stiffness of the corrugated steel plates and the confinement effect were found to be directly proportional.Additionally,a relationship was established between the average lateral stress of the concrete and the effective confinement coefficient of the CFCST through data fitting,leading to a design formula for calculating the axial compression capacity of CFCST columns.Finally,the accuracy of the formula and its applicability in engineering design were confirmed through validation on experimental data,with the maximum deviation being within±5%.
基金The financial support of this work came from the project of National Natural Science Foundation of China(Grant No.51408485)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2022JM-258 and 2021JM-332)+1 种基金the Open Fund Project of Qinghai Provincial Key Laboratory of Plateau Green Building and Eco-community(KLKF-2021-001)thanks a lot for the financial support of the above institutions.
文摘To research the axial compression behavior of steel reinforced recycled concrete(SRRC)short columns confined by carbon fiber reinforced plastics(CFRP)strips,nine scaled specimens of SRRC short columns were fabricated and tested under axial compression loading.Subsequently,the failure process and failure modes were observed,and load-displacement curves as well as the strain of various materials were analyzed.The effects on the substitution percentage of recycled coarse aggregate(RCA),width of CFRP strips,spacing of CFRP strips and strength of recycled aggregate concrete(RAC)on the axial compression properties of columns were also analyzed in the experimental investigation.Furthermore,the finite element model of columns which can consider the adverse influence of RCA and the constraint effect of CFRP strips was founded by ABAQUS software and the nonlinear parameter analysis of columns was also implemented in this study.The results show that the first to reach the yield state was the profile steel in the columns,then the longitudinal rebars and stirrups yielded successively,and finally RAC was crushed as well as the CFRP strips was also broken.The replacement rate of RCA has little effect on the columns,and with the substitution rate of RCA from 0 to 100%,the bearing capacity of columns decreased by only 4.8%.Increasing the CFRP strips width or decreasing the CFRP strips spacing could enhance the axial bearing capacity of columns,the maximum increase was 10.5%or 11.4%,and the ductility of columns was significantly enhanced.Obviously,CFRP strips are conducive to enhance the axial bearing capacity and deformation capacity of columns.On this basis,considering the restraint effect of CFRP strips and the adverse effects of RCA,the revised formulas for calculating the axial bearing capacity of SRRC short columns confined by CFRP strips were proposed.
