In this paper, the results of model tests of impact energy and forces of moored ships from 20,000 dwt to 200,000 dwt in regular waves upon piers ace synthetically analyzed. Based on the concept of Wave energy transmission and the theory of vibration, a semi empirical formula for evaluating impact energy and forces are proposed.
In the design of detached piers or platforms in unprotected water areas, the impact loading of ship in waves upon the piers is one of the important problems that are mostly concerned by engineers. Recently, a model test investigating the impact and mooring loading of a 200,000 dwt ship upon a detached pier has been performed by the authors. The dimensions, of the prototype ship are: 315 m in length " 52 m in width and 26 m in depth. Three loading, conditions were taken in the tests, i.e., fully loaded with displacement tonnage of 255,600 t" half loaded with displacement tonnage of 166,000 t and ballasted with displacement tonnage of 106,000t, with drafts of 18.2, m. 13.1 m and 9.1 m for, each " case respectively. The natural frequency of rolling, of the prototype ship is 16,6 s. Together with the previous model studies on the i:m;p.act and mooring loadings of 20,000 dwt, 50,000 dwt ships upon piers by the authors (Gao, 1975 Huang et aI, 1988) and the tests of 20,000 dwt (Li,1982) and 50,000 dwt and 100,000 dwt; (Li, 1985) by other researchers in China, a synthetic analysis is worked out in this paper. Based on the concept of wave energy transmission and the theory of vibration, a semi-empirical formula is proposed for simplifying the evaluation of the impact energy and force of ship in regular waves upon the detached piers.