Implications of seismic design aspects on a pile supported wharf structure

This paper illustrates the design issues of a pile supported wharf in a high seismicity area in Indonesia, a commonplace port structures in which the seismic response involves significant pile–slope interaction. Pile design in high-seismicity liquefiable areas involves different aspects of earthquake geotechnical engineering with important consequences both on structural and geotechnical calculation. For the structural design, non-linear soil structure interaction (pseudo-static analysis) has been considered. Moreover, in the geotechnical design, liquefaction mitigation measures and global stability assessment have been treated. The global stability assessment of the structure is deeply affected by simplified design methodology. In particular the hypothesis of simultaneous occurrence of maximum inertial forces and liquefaction during a seismic event is an assumption full of consequences in the current practice of geotechnical design in liquefiable soils; although international codes do not provide any specific recommendation. Such an example eventually shows very clearly that absence of precise recommendations may lead to an over conservative design.