Structural performance investigation of ship lift hoist pile structure exposed to tropical marine environment

This paper presents a field investigation and numerical analysis of a ship lift hoist pile structure exposed to the marine environment. This structure is located at Lamong Gulf in East Java Indonesia. This study focused on analyzing the structural performance of the steel pile of the ship lift hoist structure against gravity and seismic load. The field investigation was conducted using several methods such as visual observation, ultrasonic pulse velocity, half-cell potential and ultrasonic thickness to observe the current condition of the structure. Furthermore, a structural analysis was also performed to investigate the performance of the structure before and after the corrosion presented. Based on the field investigation result, it was found that the steel pile of the hoist structure suffers a loss of thickness due to corrosion. The thickness loss of each pile varies from 0 to 1.9 mm. The half-cell potential on the pile cap also shows that the corrosion potential in more than half the hoist pile cap is very high. Furthermore, the structural performance analysis shows that the hoist pile structure is within the safe limit against gravity load when receiving a maximum ship load of 1,650 tons. However, when the gravity load is combined with seismic load, the analysis result shows that the steel pile structure is overstressed and cannot withstands the applied load.