Experimental and computational assessment of shear beams as earthquake resilient measure for double-column piers supported by pile-group

Abstract

The double-column pier with energy dissipation members is an effective way for achieving the seismic resilience of bridges. However, there is short of shaking table tests to assess the impacts of the energy dissipation member on the seismic response and soil-foundation-structure interaction (SFSI) of the double-column pier. Therefore, this paper aims to evaluate the effects of the shear beams on the seismic response of the double-column pier supported by the pile-group in the mixed soil, rather than the cable-stayed bridge model. Two types of double-column piers-one is a conventional double-column pier, and the other is a new double-column pier with shear beams-were built and studied in a 1/70-scale cable-stayed bridge model using shaking table tests. The dynamic characteristics, seismic responses, and SFSI effects between two types of double-column piers were compared under different earthquake waves. Test results revealed that the shear beams significantly decreased the reinforcement strain and the bending moment of the double-column pier. The SFSI effects on the double-column pier with shear beams are more significant than the double-column pier. Also, the computational model developed in OpenSees could reproduce the seismic responses of the double-column piers with and without shear beams and detect the seismic response variations induced by the shear beams. The shear beam was earlier yielding than the column and dissipated the earthquake input energy so that the column could remain elastic under the El Centro with 1.4 g. Consequently, the effects of the shear beam on mitigating the seismic damage and enhancing the seismic resilience of the double-column pier were validated.