Seismic response of multi‐span simply supported bridges to a spatially varying earthquake ground motion

Abstract

SUMMARYThis paper carries out a parametrical study of the pounding phenomenon associated with the seismic response of multi-span simply supported bridges with base isolation devices. In particular, the analyses focus on the causal relationship between pounding and the properties of a spatially varying earthquake ground motion. In order to include the e ect of the torsional component of pounding forces on the seismic response of the whole structure, a three-dimensional (3D) ÿnite element model has been deÿned and 3D non-linear time-history analyses have been performed. A parametrical study on the size of the gaps between adjacent bridge decks has highlighted that the pounding e ects are ampliÿed when the spatially varying ground motion time histories at each support are considered. Because of a spatially varying input, the pounding forces can assume values 3-4 times larger than those derived by a conventional seismic analysis with uniform input or with spatial input but considering ground motion wave passage e ect only. The numerical results show that in order to achieve an acceptably safe structural performance during seismic events, a correct design of the isolation devices should take into account the relative displacements calculated by means of a non-linear time-history analysis with multi-support excitation.

Non-linear viscoelastic modelling of earthquake-induced structural pounding

“…Several types of such elements, e.g., a linear spring, a bi-linear spring, a linear spring-damper and a non-linear spring, have been used for the simulation purposes. The simplest impact element consists of a linear elastic spring and does not account for the energy dissipation during collision [8,11,28,29]. The bi-linear spring element with di erent approaching and separation sti ness has been described by Valles and Reinhorn [30].…”

Influence of soil-structure interaction on pounding response of adjacent buildings due to near-source earthquakes

“…Fig. 1(h) (12) Using the governing equation of the uncondensed system we define the corrective result {un} due to the unbalanced load.…”

Behaviour of integral bridges under vertical and horizontal earthquake ground motion

“…interaction of all three components, for analytical simplicity researchers have divided this phenomenon into these three sources (Burdette & Elnashai, 2011). Zanardo et al (2002) stated that analyses of different cases showed that the spatial variation properties of the earthquake ground motion can drastically change the structural response of the bridge. Sextos et al (2004) stated that asynchronous motion cannot easily be replaced by an alternative reference uniform motion.…”