Model studies on monopile foundation systems under long-term repeated lateral loads

Abstract

Wind energy plants, dolphins, and many other ocean engineering structures are supported on large diameter rigid monopiles. For such structures lateral loads are more critical for the design and analysis compared with the gravitational loads and foundation piles are required to withstand a large number of repeated lateral load cycles during their design life. In such applications, the lateral forces and bending moments resulting from wind/wave loadings must be economically and safely transferred to the sea bed. Such requirements make the pile response deflection sensitive in addition to be load earring capacity posturing. The behaviour of large diameter rigid monopiles in general, under long-term low-amplitude repeated lateral loading, is not well documented. Existing methods for estimating the accumulated lateral strain (rotation) response of monopiles are based on very limited field/experimental laboratory data and are currently not capable of explicitly accounting for site-specific soil properties and loading characteristics.