Determining initial pretension values of pre-stressed cables is one of the key problems for a steel mega frame and pre-stressed composite bracing structure.Through the mechanical analysis of the composite bracing unde...Determining initial pretension values of pre-stressed cables is one of the key problems for a steel mega frame and pre-stressed composite bracing structure.Through the mechanical analysis of the composite bracing under vertical loading,the critical factors deciding the initial pretention value were found.According to these factors,a rule for the initial pretension value was put forward.The determination equations were acquired based on the principle of force equilibrium at nodes.The numerical results indicate that the internal force disequilibrium in composite bracings resulted from symmetrical load can be eliminated only in a symmetrical way,so that initial pretention values are decided only by vertical loads.The influencing coefficient leveling method,taking into account interactions between story and story,is accurate and feasible.展开更多
A "mega-earthquake" is one with an intensity larger than the most severe earthquake intensity category currently considered in design codes. For a "mega-earthquake," the design objective of a given...A "mega-earthquake" is one with an intensity larger than the most severe earthquake intensity category currently considered in design codes. For a "mega-earthquake," the design objective of a given structure is to "preserve living spaces for people in the buildings." In this paper,factors that may influence the collapse resistance of RC frames in a mega-earthquake are analyzed based on seismic damage observed in the 2008 Wenchuan earthquake. Methodologies to improve structural collapse resistance focus on three aspects:global strength margin,global redundancy and global integration of the structural system. Fundamental principles and design concepts for collapse prevention under a mega-earthquake are proposed,and issues that need further research are identified.展开更多
基金Project of Ministry of Housing and Urban-Rural Development of China(No.2012-K2-28)
文摘Determining initial pretension values of pre-stressed cables is one of the key problems for a steel mega frame and pre-stressed composite bracing structure.Through the mechanical analysis of the composite bracing under vertical loading,the critical factors deciding the initial pretention value were found.According to these factors,a rule for the initial pretension value was put forward.The determination equations were acquired based on the principle of force equilibrium at nodes.The numerical results indicate that the internal force disequilibrium in composite bracings resulted from symmetrical load can be eliminated only in a symmetrical way,so that initial pretention values are decided only by vertical loads.The influencing coefficient leveling method,taking into account interactions between story and story,is accurate and feasible.
基金National Natural Science Foundation of China Under Grant No.90815025 The National Key Technologies R&D Program Under Grant No.2009BAJ28B01,2006BAJ03A02-01 for Changjiang Scholars and Innovative Research Team in Universities
文摘A "mega-earthquake" is one with an intensity larger than the most severe earthquake intensity category currently considered in design codes. For a "mega-earthquake," the design objective of a given structure is to "preserve living spaces for people in the buildings." In this paper,factors that may influence the collapse resistance of RC frames in a mega-earthquake are analyzed based on seismic damage observed in the 2008 Wenchuan earthquake. Methodologies to improve structural collapse resistance focus on three aspects:global strength margin,global redundancy and global integration of the structural system. Fundamental principles and design concepts for collapse prevention under a mega-earthquake are proposed,and issues that need further research are identified.
