Wharf Movements Due to Tidal Fluctuations

Movements of a pile-supported wharf due to tidal fluctuations acting on unstable sediment mounds are described and analyzed. A 244 meter long by 61.5 meter wide general cargo wharf (Berth 14) at Port Klang, Malaysia has moved approximately 135 millimeters horizontally since its construction in 1963. Results of a detailed investigation are summarized, along with an analysis conducted for the structure. A detailed geotechnical study was completed to characterize the soil, both within and underlying the sediment mounds down to firm bearing horizons for deep foundations. Additionally, a short-term tidal fluctuation movement- monitoring program was completed to measure the movements of the wharf during the peak tidal cycles. The gaps at the expansion joint between the access trestle and the wharf were measured at high and low tides for correlation purposes. The data gathered in the field confirmed movement of the wharf and supporting piles. Secondly, it allowed determination of maximum permissible dredge depth for the berth. Thirdly, it provided a determination of the cause of the movement. A correlation between the measured movements in the berth and empirical relationships for lateral load on piles was established using the procedure documented by C. Vigianni (1981) and a finite element model of the berth.