In order to validate the accuracy of nonlinear fire simulation programs,comparison analysis is carried out between simulation and experiment induced from small-scale specimens,and then fire resistance of large-scale p...In order to validate the accuracy of nonlinear fire simulation programs,comparison analysis is carried out between simulation and experiment induced from small-scale specimens,and then fire resistance of large-scale prestressed concrete slabs is further investigated through parameter expansion.The influences on fire resistance ratings controlled by deflection are explored and discussed,including effective span,concrete cover thickness,load level,prestress degree,effective prestress,composite reinforcement index and other factors.The calculated results indicate that fire resistance ratings of large-scale bonded prestressed concrete simply supported slabs are bigger than those of small-scale ones.Finally,the calculation formulas of fire resistance ratings controlled by deflection are established,which rationally consider the influence of effective span,concrete cover thickness,load level,composite reinforcement index and so on key factors.展开更多
As the influence of the ratio of the characteristic value of structural resistance to that of frequent combination effect, K, on the thickness of concrete cover of prestressed concrete （PC） beams and slabs for fire ...As the influence of the ratio of the characteristic value of structural resistance to that of frequent combination effect, K, on the thickness of concrete cover of prestressed concrete （PC） beams and slabs for fire resistance is not considered sufficiently in design criteria for concrete structures in China and other countries at present, numerical analyses were carried out by ANSYS software on unbonded prestressed concrete （UPC） oneway simply-supported and continuous slabs and beams, and bonded PC simply-supported and continuous beams subjected to fire in 186 cases. In the analysis, K, section dimensions and the thickness of concrete cover are regarded as independent variables and some calculation parameters determined by trial and error based on test resuits. Calculation formula for fire endurance of UPC simply-supported and continuous slabs was proposed, and the recommended thicknesses of cover of PC beams and slabs was presented in consideration of the influence of K and section dimensions as well as fire endurance requirements. Comparison analysis of relevant design criterions in China and other countries was performed to verify the rationale of the proposed values.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.50678050)
文摘In order to validate the accuracy of nonlinear fire simulation programs,comparison analysis is carried out between simulation and experiment induced from small-scale specimens,and then fire resistance of large-scale prestressed concrete slabs is further investigated through parameter expansion.The influences on fire resistance ratings controlled by deflection are explored and discussed,including effective span,concrete cover thickness,load level,prestress degree,effective prestress,composite reinforcement index and other factors.The calculated results indicate that fire resistance ratings of large-scale bonded prestressed concrete simply supported slabs are bigger than those of small-scale ones.Finally,the calculation formulas of fire resistance ratings controlled by deflection are established,which rationally consider the influence of effective span,concrete cover thickness,load level,composite reinforcement index and so on key factors.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50678050)the Outstanding Youth Science Foundation of Heilongjiang Province(Grant No.2001-8)
文摘As the influence of the ratio of the characteristic value of structural resistance to that of frequent combination effect, K, on the thickness of concrete cover of prestressed concrete （PC） beams and slabs for fire resistance is not considered sufficiently in design criteria for concrete structures in China and other countries at present, numerical analyses were carried out by ANSYS software on unbonded prestressed concrete （UPC） oneway simply-supported and continuous slabs and beams, and bonded PC simply-supported and continuous beams subjected to fire in 186 cases. In the analysis, K, section dimensions and the thickness of concrete cover are regarded as independent variables and some calculation parameters determined by trial and error based on test resuits. Calculation formula for fire endurance of UPC simply-supported and continuous slabs was proposed, and the recommended thicknesses of cover of PC beams and slabs was presented in consideration of the influence of K and section dimensions as well as fire endurance requirements. Comparison analysis of relevant design criterions in China and other countries was performed to verify the rationale of the proposed values.
