| Reinforced concrete(RC)frame is a popular structure style in the world.Constrained by economic conditions,technology and construction management level,the seismic capacity of building structures in developing countries is relatively weak compared with developed countries.Strong earthquakes brought greater threats and disasters to developing countries.Over the years,earthquake disasters shown that beam-column joint failure was found in RC frame,which even led to structure collapse.At present,seismic reinforcement methods for RC beam-column joints are more suitable for developed countries in terms of cost,materials and technical requirements.In this study,a simple and practical seismic reinforcement method is developed for RC frame structures with weak beam-column joints in developing countries.It is shown in this paper that the finite element analysis using ANSYS model of RC exterior beam-column joint without joint core shear reinforcements,which is from the building damaged in 2009 Sumatra earthquake in Indonesia,verifies feasibility and reliability of the simulation for strengthening beam-column joints with installed wing walls under earthquake.Moreover,using finite element method,strengthening effectiveness for RC interior beam-column joint("+" shape joint)designed according to the details of exterior beam-column joint was analyzed through quasi-static analysis,taking the number and arrangement of wing walls into account.It is found that it can be installed to only one side of the columns to obtain the same strengthening objective of a beam-yielding failure mode as that when wing walls were installed to both sides of the existing columns.The finite element model of two layers and two spans RC plane frame structure was established,then Pushover and quasi-static analysis were carried out respectively.It is found that shear failure of joints occurs in the plane frame without reinforcement,and seismic performance of the plane frame reinforced by wing walls is greatly improved achieving beam-yielding failure mode.Seismic behavior of the frame under different wing wall arrangements is analyzed,and a strengthening method by wing walls of strengthening the frame structure is proposed,which aims at forming beam-yielding failure mode,in consideration of the construction cost,construction period,labor force,internal space occupation and using function of the structure.In this paper,the design theory of strengthening interior beam-column joints by wing walls is proposed.In addition,based on the control of deformation of the structure,the seismic reinforcement design method of the frame structure is presented,which lays a foundation for the engineering application of strengthening RC frame structures with weak joints by wing walls. |
PDF Full Text Request