Extreme value distribution and dynamic reliability estimation of high-pier bridges subjected to near-fault impulsive ground motions

Abstract

The seismic behaviour of high-pier and long-span bridges in fault zones is significantly influenced by the near-fault impulsive effect. In view of this, this study evaluates the extreme value distribution and dynamic reliability of high-pier bridges built in fault zones. First, based on the improved maximum entropy method constrained with fractional moments, a new method is proposed to evaluate the extreme value distribution of nonlinear structure seismic response. In the proposed method, the fractional moments are evaluated by the Latin hypercube sampling, and a linear system of equations that determine the initial value of fractional exponents and Lagrange multipliers is illustrated to improve the stability of the simplex algorithm. Second, based on the obtained extreme value distribution, the seismic reliability of structure is estimated by the simple numerical integration. Two numerical examples, including a nonlinear single-degree-of-freedom system and a three-storey nonlinear shear frame, are adopted to validate the proposed method. Finally, the seismic reliability of a typical high-pier and long-span continuous rigid frame bridge located in southwest of China is evaluated by the proposed method and some critical conclusions are drawn. The results obtained from this study not only indicate the accuracy and efficiency of the proposed method but also can provide some direct guidelines for the seismic design of the high-pier and long-span bridges in fault zones.