Developing a Resilience Index for the Pile-Supported Piers of the Port of Batangas under Tsunami Load

Abstract

The roll-on/roll-off (ro-ro) transport system, which plays a huge role in the transportation and economy of the Philippines, mainly uses piers to provide smooth berthing of ships. However, its structural configuration attracts different hazards causing damage, particularly to piles. Tsunamis produce devastating wave forces. This may heavily result in discontinuity of the whole port operation as there will be no available berthing structure for ships. Hence, this study was conducted to determine the structural resilience of the pile-supported piers of the Port of Batangas against tsunami loads at different variations of wave height and water depth. Structural software was used to model the piers and incorporate calculated tsunami drag forces. Furthermore, pushover analysis was performed to produce the base shear versus displacement curves needed for the calculation of the robustness index. The rapidity index, on one hand, is based on an interview with the Philippine Ports Authority - Port Management Office (PPA-PMO) of Batangas resulting in recovery rates for demolition works and pile replacement. Combining these indices using the concept of resilience triangle, values of the resilience index ranging from 0.0 to 1.0 were calculated at both longitudinal and transverse directions. As a result, the piers were categorized as highly resilient in almost 50% of the tsunami load cases. It proved that the pier with existing batter piles exhibits higher resilience than the other which is only supported by vertical piles.