Babak Ebrahimian - Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran
Amir Hossein Shamshirgaran - Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran

This paper presents a comparative study to assess the ultimate axial compressive bearing capacity of offshore piles in two major marine bridge projects using piling records and field test results. The main objective is to propose a reliable methodology for designing offshore piles in both predominantly clayey and sandy sites. To this end, the results of four detailed full-scale pile loading tests (PLTs and PDAs) and high quality piezocone (CPTu) results adjacent to highway-bridge pile foundations of Urmiyeh lake causeway in Iran, and Tokyo port bay bridge in Japan, have been derived from the international scientific literature and employed in the analyses conducted in this research. Thirteen common estimation approaches are used to determine the axial compressive bearing capacity of offshore piles, four of which are based on static analysis and the rest are direct CPT-and CPTu-based methods. The prediction quality of different calculation methods is evaluated via six statistical criteria. The results show that the developed direct CPT- and CPTu- based methods propose higher accuracy in predicting the ultimate bearing capacity values rather than the employed static analysis methods in the both sites. Furthermore, the direct CPTu-based approaches are more reliable than CPT-based methods as time elapses.

Offshore piles, marine bridge, axial bearing capacity, CPT, static methods.