Earthquake Response of Long-Span Suspension Bridges

摘要

The earthquake response of long-span suspension bridges subjected to multiple-support seismic excitations for vertical, torsional, and lateral vibrations is investigated. Ground motion inputs are taken from existing ground motion records and compared to artificially generated records. A relatively large number of modes, closely spaced in frequency domain, is found to participate in the earthquake response of a suspension bridge. The vibrational stresses induced in the cable-suspended structure under multiple-support excitation are determined to be live loads that may come close to or exceed design yield stresses. It is concluded that the properties of soils underlying the bridges' foundations should be estimated and considered when designing the bridges.