Title: Seismic Performance of Unreinforced Concrete Railroad Bridge Piers

Author(s): Qiang Gui, Zhongguo John Ma

Publication: Web Session

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Date: 3/24/2019

Abstract:
Unreinforced concrete railroad bridge piers show better-than-expected performance based on the post-earthquake survey records. The restraining effect of rail track structure is hypothesized in railroad design code to contribute to it. Several full-scale field experiments were conducted to investigate this restraining effect on the ultimate strength of railroad bridges subjected to lateral pushing load at span ends. However, limited study was conducted to evaluate the unreinforced concrete piers related to this restrain effect. This presentation firstly introduces a structural modelling scheme for quantifying the restraint stiffness of rail track system applied horizontally to the top of the unreinforced concrete pier. The scheme considers the nonlinear behavior of bearings and ballast structure and is calibrated and validated by the previous full-scale field tests. Then, the seismic performance of unreinforced concrete piers is evaluated based on the dynamic analysis and shaking-table model testing. The influence of the top restraining effect on the dynamic behavior of unreinforced concrete piers, e.g. vibration modal, damage mode, energy dispersion, will be discussed with respect of the damage modes of these piers in past earthquakes. The findings of this study are expected to assist engineers for the strength evaluation of numerous existing unreinforced concrete piers for an extended design life.