Effect of Soil-Structure interaction on energy dissipation and shock absorption of swing column control devizce

Abstract

The role of the bridge piers is mainly to bear the load of the superstructure and transfer the load to the foundation. Excessive lateral displacement of the bridge piers under earthquake action can lead to the overall destruction of the bridge structure. In this paper, an improved Swing Column Control Device (SCCD), which is mainly composed of a swing column and Tuned Viscous Mass Damper (TVMD), is proposed to improve the lateral movement stiffness and energy dissipation capacity of the bridge piers and protect the bridge structures from damage under external loads (seismic waves and wind loads). The impact of Soil-Structure Interaction (SSI) on the energy dissipation and shock absorption of the SCCD is not negligible due to the large mass of inertia coming from TVMD. To verify the correctness and effectiveness of this control strategy, based on the theory of elastic half-space and swing-rotation model, the motion equation of the bridge piers with SCCD was established and solved by programming. The case study provided in this paper shows that the bridge pier with SCCD installed on a rigid foundation has a significant absorbing vibration under unidirectional seismic wave. The displacement reduction rate of SCCD for bridge piers built on flexible foundations (category Ⅱ sites) ranges 10% to 16%, even with partial enlargement of displacements on other types of sites. The effects of SSI have weakened the absorbing vibration effect of bridge pier with SCCD constructed on flexible foundations. Therefore, it is necessary to consider SSI when using SCCD to strengthen the bridge piers. Another interesting finding in this paper is that flexible foundations also reduce the displacement response of the superstructure, but the acceleration response of the superstructure is affected by the nature of the seismic waves demonstrating the reverse absorbing vibration.