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SUMMARYPast severe earthquakes indicate that pounding may cause considerable damage or even lead to collapse of colliding structures. The aim of this paper is to present an analysis of pounding between superstructure segments of an isolated elevated bridge induced by the propagating seismic wave. High-damping rubber bearings (HDRBs), used as isolation devices, are modelled by proposed non-linear formulation and the significance of the bearings model for pounding is indicated. The results of the study show that pounding leads to the increase or decrease of the forces acting on piers, depending on the gap size between superstructure segments.1998 John Wiley & Sons, Ltd.

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This paper investigates inspection of reinforced concrete elements sensitive to the splitting failure. The behaviour of a reinforced concrete specimen subjected to a tensile stress is considered. The damage detection procedure is based on the ultrasonic wave propagation technique. The piezoelectric transducers are located on both ends of the specimen and the measurements are taken periodically during the incrementally increased loading. The features of measured signals in time and frequency domains as well as wavelet transforms before and after the splitting failure are studied. The experimental results show that proposed method can be used for monitoring of damage evolution in concrete elements. The method makes possible detection of the moment just before the splitting failure occurs.

SUMMARYPounding of adjacent superstructure segments in elevated bridges during severe earthquakes can result in signi"cant structural damage. The aim of this paper is to analyse several methods of reduction of the negative e!ects of collisions induced by the seismic wave propagation e!ect. The analysis is conducted on a detailed three-dimensional structural component model of an isolated highway bridge. The results show that the in#uence of pounding on the structural response is signi"cant in the longitudinal direction of the bridge and signi"cantly depends on the gap size between superstructure segments. The smallest response can be obtained for very small gap sizes and for gap sizes large enough to prevent pounding. Further analysis indicates that the bridge behaviour can be e!ectively improved by placing hard rubber bumpers between segments and by sti! linking the segments one with another. The experimental results show that, for the practical application of such connectors, shock transmission units can be used.