Impact of load combination on the stability analysis of an arch dam subjected to stochastic non-uniform excitations

Abstract

In the present paper, impact of the non-uniform excitation due to spatially varying earthquake ground motion (SVEGM) is investigated on the linear response of a typical concrete arch dam. An iterative scheme is utilised to generate the stochastic acceleration time histories at several locations along the foundation boundaries which are compatible with the target response spectra and are correlated according to a given complex coherence function. A typical arch dam is selected as the case study in which the reservoir is modelled as a compressible medium and the foundation is assumed to be massless. Various load combinations are considered based on the corresponding reservoir water levels and the thermal loads. It is observed that, in general, considering SVEGM leads to higher tensile stresses and increases the percentage of the overstressed area within the dam body especially in vicinity of the foundation in comparison with uniform excitation. Thus, for more realistic assessment of the dam behaviour, SVEGM effect should be incorporated in seismic analyses especially in high seismicity regions.