SEISMIC RESPONSE OF DOUBLE-COLUMN BRIDGE PIERS ON ELASTO-PLASTIC WINKLER FOUNDATION

For bridge piers with shallow foundation subject to intense earthquake excitations, the uplift of foundations occurs and the foundation soils enter into plasticity. It is rather difficult to simulate the uplift and yield of supporting soils accurately. An improved Winkler foundation model taking into account the uplift and yield of foundation is employed in the analysis. A tri-linear hysteretic model is employed in the analysis of reinforced concrete bridge piers. The El Centro earthquake record in 1940 is inputted to a double-column bridge pier with shallow foundation so that the nonlinear history response is obtained. It is concluded that the uplift and yield of supporting soil have important effect on the seismic response of double-column bridge piers. Compared with that of linear analysis, the displacement of the double-column piers increases and the internal force decreases. It is shown that the consideration of uplift and yield of foundation in design is significant in protection of bridge piers.