Seismic Ductility Of Concrete Viaduct Piers And Design Of Steel Reinforced Plastic Hinges

Seismic design of bridge pier usually allows the plastic hinge appears in the specific parts of the pier under the strong earthquake, in order to resist earthquake by the energy dissipation of the plastic hinge. Ordinary reinforced concrete bridge pier usually couldn’t supply enough displacement ductility of structure needed. In this paper discusses that FRP jacket is used to improve the ductility in the potential plastic hinge region of reinforced concrete viaduct pier. The main contents in this paper are described as follows:1. Based on the stress-strain relation of confined concrete and the calculate assumption, a Matlab program that can draw moment-curvature curve of RC columns using FRP (Fiber reinforced Plastics) jackets with rectangular section is developed. And the main influence factors of curvature ductility of FRC(FRP reinforced concrete) pier are analyzed by this program.2. The formula of yield curvature and limit curvature of FRC section is derived theoretically and the expression of ductility factor is simplified. And then the feasibility of ductility factor has been tested and verified through the comparison with available experimental data.3. The design of ductility of plastic hinge and the analysing of rectangular piers with CFRP jackets of the viaduct bridge are given, and the pier is divided into three sections:the plastic hinge section, transition section and ordinary section. Then a finite element model is established which can exactly describes material properties by the finite element software to simulate the seismic performance of the pier under the strong earthquake. A calculation comparison with ordinary reinforced concrete pier is made under the premise of same reinforcing steel ratio, by which an estimate is given about the extent of the increasing of ductility performance of plastic hinge with CFRP jackets, and a design method is proposed based on this analysis.