Study On Spatial Collapse Responses Of Reinforced Concrete Frame Structures Under Earthquake

A new 3D numerical model for collapse analysis of reinforced concrete (RC) frame structures is developed by discretizating a structure into beam elements, column elements and joint elements or into column elements and slab elements, constructing concrete springs and steel-bar springs on the interfaces between elements to represent the tensile, compressive, bending, shearing and torsional behavior of the elements, and defining the constitutive relations with failure criterion for springs. Introducing the numerical integral technique which is applicable to rigid elements with three greatly different principal moments, presenting practical calculation equations for structural dumping coefficients and calculation technique for integral time step, the discrete element method (DEM) is developed. Based on this new model and improved DEM, a software system is developed to simulate spatial responses of RC frame structures on the Visual C++ develop platform. Verifying the simulation system by the shaking table test of a RC frame model structure and other analysis examples covering single-degree-of-freedom systems and multiple-degree-of-freedom systems, elastic problems and elastoplastic problems, small-displacement analysis and large-displacement analysis, it can be concluded that the simulation system can commendably simulate the collapse responses of RC frame structures by choosing rational discretization method and constructing connective springs with appropriate hysteresis models under arbitrary routes of loading. The simulation system developed here can be used as an assistant tool for design of new building structures and assessment of existing building structures.