Transient responses of girder bridges with vertical poundings under near‐fault vertical earthquake

Abstract

SUMMARYPrevious studies on pounding responses of bridge structures mainly focus on the horizontal pounding between adjacent structures. However, the vertical pounding responses of bridge are rarely studied. The aim of this paper is develop a theoretical approach to investigate the transient behavior of continuous bridge under near-fault vertical ground motions. The transient behavior of bridge manifests as the earthquake-induced response wave and pounding-induced response wave travel throughout bridge. Based on a new continuous model of beam-spring-rod, the theoretical solution of bridge responses involving multiple vertical poundings is derived by the expansion of transient wave functions in a series of eigenfunctions. A new theoretical solving approach of the multiple vertical pounding forces is presented based on the transient internal force on the contact surface of the girder and bearing. The numerical results show that the present method can reasonably capture the propagations of the earthquake-induced response wave and pounding-induced response wave. The calculations of pounding force by the present method are convergence of the time-step size and truncation number of wave modes. As the effect of transient wave is taken into account, the numerical results show several transient phenomena involving the vertical pounding, the high pounding force, the multiple-pounding phenomenon, the vertical separation of girder from the bearing, the dependence of poundings on earthquake period and the narrow period window of poundings.

Influence of Pier Size on its Failure Mode under Near-Fault Vertical Earthquake

“…e ratio of vertical seismic acceleration to horizontal acceleration in the near field is 2/3, which may underestimate the vertical seismic effect. For the value of V/H in the follow-up study, please refer to literature [24]. e specific formula is as follows:…”

“…e separation will increase the vertical contact force and change the longitudinal dynamic response of the bridge. For the impact force of the pier-beam, Yang and Yin [24] theoretically calculated the change of impact force of the pierbeam under different excitation conditions and structural parameters. Chen et al [25] calculated the influence of pier and beam separation under different excitation conditions on the bending failure of the pier.…”

Analytical Fragility Curves for Seismic Design of Glass Systems Based on Cloud Analysis

“…When possible, however, more complex setup configurations should be necessarily taken into account even for vertical load-bearing elements [63]. The vertical ground components should be definitely included for horizontal glass members (like slabs, roofs, or walkways that are sensitive to vertical vibrations [64]), in the same way of other constructional systems [65][66][67].…”

Transient Response of Bridge Piers to Structure Separation under Near-Fault Vertical Earthquake

“…In this study, a double-span continuous beam bridge model is established, and the forced resonance response of the bridge is calculated by using the transient wave function method [30]. The structural displacement response caused by the collision force is calculated by using the indirect modal function method [31]. The force and displacement response of the bridge are calculated by the theoretical approach, and the bending conditions of the bridge pier under different conditions are obtained.…”