Stick-up stability of large-diameter steel pipe pile considering combined wave-current loads

With the increase of water depth in marine construction projects, characteristics of large diameter and deep penetration appear in the steel pipe piles used for jacket platform. Because the bearing capacity of piles is improved, constructions of piles become more difficult. It results in the need of hammers with larger blow energy and higher demand for safety in pile driving. The stick-up stability of piles is the first important part in the analysis of pile driving. Considering the transient characteristics of hammer load, a dynamic method is adopted to calculate the wave and current loads, and a dynamic simulation method is proposed to analyze the stick-up stability of pipe piles. The results show that the calculation of stick-up using the API code, which is different from the transient process and considers the long-term effect of load, is conservative. The API code can be used to check the stick-up stability of piles, and the strength reduction factor can be magnified 1.5 times.