Reinforced Concrete Pier Ductility Reinforcement Pilot Study

A large number of experimented researches and earthquake indicate that most damages belong to the areas of plasticity hinge of piers in server earthquake, because piers lack curve ductility. Strengthening reinforced concrete piers with Fiber Reinforced Plastic (FRP) and hoop stirrup are extensively paid attention at present. The text makes four reinforced concrete pier models. Three of them are strengthened by three different materials and tested to research the ductile capacity of piers and analyzed strengthen effects.Main research work is as follows.On the basis of describing the basic theory and method of ductility anti-seismic design, the equations of circular piers' ductile parameters are deduced, which establishes the theoretical foundation for analyzing strengthening piers' ductility.The models are designed simply as the background with 20m simple T bridges designed of "Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts "(JTJ 023-85) and static force similitude. The ratio of reinforcement, reinforcement stirrup, concrete mark and laying method of piers are similar to prototype ones. After the standard maintenance date, three different materials are adopted in reinforcing piers: Glass Fiber Reinforced Plastic (GFRP), Aramid Fiber Reinforced Plastic (AFRP) and hoop stirrup reinforce pier models separately in the same original press and are compared with the one without reinforcement. One dimension simulation static test is adopted, which uses displacement control. MTS system of U.S.A is applied to test the ductility of four test piers and the test data information is collected.Three reinforcement test piers' ductility is analyzed through hysteric curve and skeleton curve. The result expresses that the strengthened piers' maximum resisting power ,ductility and dissipating energy capacity are all increased compared with un-strengthened. The order of increase is AFRP, GFRP and hoop stirrup.Considering from economic benefit and strength of materials' exertion, strengthening piers with hoop stirrup not only increases the seismic ductility, but also saves strengthening investment. The research findings of the thesis can be supplied references to the same kind piers' ductility strengthen.