The Dynamic Loads for the Strength Design of Moored Offshore Structures under Storm Conditions
Designs are under study of a surge barrier across the largest estuary of The Netherlands. In one of the designs a horse-shoe-type pontoon provided with a huge gantry crane would be used for transportation and installation of concrete modules weighting up to 10,000 tons. The crane pontoon carrying the heavy module has to withstand the storm conditions when it is moored by anchor wires in the open sea.This paper deals with the method applied to calculate the dynamic loads on complicated floating structures in a number of regular waves with unit wave amplitude. Per wave frequency the dynamic loads are inserted in a strength analysis program resulting in the wave frequency stresses. By means of spectral analysis the most probable maximum dynamic stresses occurring once during a storm are predicted. Some model tests on a rigid scale model of the crane pontoon were carried out. Good agreement between the calculated and model measured wave generated loads is shown.