Upgrading of RC Beam-Column Connections with Steel Jacketing under Seismic Loads

Performance of reinforced concrete frames is highly depended on detailing of the ductile connections based on the philosophy of strong column-weak beam. There are several methods for seismic upgrading of connections. In this paper, using steel jacketing for seismic upgrading of Concrete Beam-Column connections subjected to constant axial and cyclic loads has been investigated using finite element method. Some experimental results are used to verify the finite element approach. Analyses are then conducted on main models upgraded with steel jackets in beam, column or both using parameters like beam jacket thickness, column jacket thickness and axial load ratio. The results are compared and the suitable model is proposed. Based on different analysis for the considered samples, several results obtained. Analysis result shows the positive impact of the use of steel jacketing for upgrading of Concrete Beam-Column connections. From these results, it can be noted that, regardless of the size of the axial load, using a steel plate increased the tangential rigidity of connection. And this increasing of rigidity in most cases is more than of increasing of final capacity of the connection. But in the case of high axial loads, the increase that can be seen in the final capacity of the connection is further of rigidity increasing. Also, depending on the size of the axial load, steel plate can increase the capacity of connection up to 7 time, and the capacity and ductility of connections was returned to better state with the average axial load.