Behavior of port structures under tsunami loading

Abstract

LPG and LNG terminals consist of loading platform, dolphins, jetties and trestles. Since these structures are required to berth large vessels for loading and unloading of the cargo they are located in near shore area. Due to that often terminals or parts of it are constructed with limited or no protection against tsunamis. After the 2004 Indian Ocean tsunami, severe damage to marine structures has been observed in many affected areas. In order to better understand responses of port structures during tsunami, an analysis of the berthing dolphin, mooring dolphin and loading platform is conducted. Behavior of port structures under hydrodynamic drag forces and buoyant forces is analyzed using linear elastic models. Tsunami amplitude and current velocity are chosen based on previous simulations and observed data. Tsunami amplitude between 1-3m and tsunami velocity between 1-3 m/s are considered in the analysis. Top deck displacement and internal forces in piles are compared and discussed. Effects of the structural and tsunami parameters on structure behavior are reported. An effect of utilization of batter piles with rake from 1:32 to 1:3 is studied. It is observed that using batter piles reduces displacement and bending moment values, however increases axial forces. For the mooring dolphin with piles raked 1:4, reduction of displacement is equal to 82% and reduction of bending moment is equal to 60% of the values of structure supported only by vertical piles.