A Study On The Applicability And Parameter Defining Method Of The Beam-Column Model In OpenSees

The earthquake response of beam-column joints in a reinforced concrete subassemblage is so complicated. Up to now, researchers from home and abroad have done a lot of studies on the aseismatic capacity and design methods of a joint. With the rapid development of numerical simulation in structure engineering field, a new way which is to construct joint model by the finite element method and computer programming to simulate the response of a joint under reversed-cyclic load is invented and developed.The primary research object is a 2-D plane model for internal joint in reinforced concrete subassemblages. This model is developed on the basis of a new structure nonlinear analysis procedure OpenSees, which is produced by the PEER center of America. On the basis of this model, the following work has been done in this paper: The first part of this paper is to deeply study and analyse the component models of the joint model separately, and evaluate its feasibility and objectivity, then study how to implement this model in OpenSees. In addition, in order to define parameters for the proposed model, a program SSVS which is based on MCFT(Modified Compresion Field Theory) is worked out to calculate the shear stress-shear strain relationship for reinforced concrete. The author proposes that use displacement loading to seek the whole curve of the shear stress-strain relationship. At the same time, by a simplistic formula, this part has calculated out the envelope curve of shear stress-strain relationship for the former joint tests, which have also been simulated based on MCFT. Through comparison and analysis, propose that"Truss Mechanism"is the main factor to lead the shear deformation of the joint core.The second part is to use this joint model along with the parameter defining program to simulate the beam-column joint experiments in the laboratory, in which the specimens were sustained reversed-cyclic load. Also, the structure models, commands, material constitutive models and the element types supported by OpenSees, have been introduced during the simulating. A program procSKPC which is based on modified Kent-Park concrete constitutive model is worked out in this part to consider the restrict effect of stirrups to concrete.In the third part, through calibrating the parameters of the primary component models, find out the critical problem of the joint model and after an analysis of the load distribution in the joint core, a method of defining parameters for the Shear Panel has been proposed. Then redefine the parameters, simulate the former joint tests a second time and gain the preferable simulated response. Based on the preferable simulated response, it indicates that with the parameters defining method in this paper, the joint model can represent well the fundamental characteristics of the beam-column joint which is under reversed-cyclic load.