Abstract
The demand for economic and reliable foundations in offshore renewable developments has resulted in a need to more accurately understand the behavior of piled foundations subject to cyclic loading. Currently little information is published on the effect of cyclic loading on piled foundations in chalk. It is believed cyclic loading can cause degradation of the chalk strength and thus of ultimate pile capacity as a result. Generally, conservative designs are adopted to mitigate against the potential risks. This paper investigates the cyclic damage threshold of chalk strata regularly encountered in the North Sea by using cyclic triaxial and simple shear tests on chalk and specifically designed chalk-grout interface simple shear laboratory tests. Improved foundation design recommendations are provided as a result of the laboratory investigation.