Hysteretic Behavior of Concrete Connections Strengthened by X-Shape FRP Strips

Different methods may be used for strengthening weak concrete connections.Because of the unique characteristics of FRP composites, they are widely used for strengthening concrete moment resisting frames. These retrofitting techniques are widely considered in research and practical applications. The retrofitting cost is an important factor in the selection of the most suitable retrofitting techniques. In the application of FRP laminates, the cost of retrofitting is mainly the function of FRP volume and the surface preparation. In this research, using ABAQUSgeneral purpose finite element software, the effect of different FRP configuration in X-shape connection strengthening scheme were considered and the results were compared with full FRP coverage of connection. In this strengthening scheme, the effect of parameters such as strip width and thickness was examined. The results showed that in strengthening with x-shape strips, the connection could develop the capacity of connection strengthened by full FRP coverage, while it needs about 16 percent less FRP laminates, which meaningfully could reduce the price of connection strengthening.