OPTIMUM DESIGN FOR ARMOR UNITS BASED ON THE MINIMUMLIFE CYCLE COST

摘要

The present paper has proposed the optimum design method which shows how to select an armor unit size of the minimum life cycle cost (LCC) for the seawall structures. The hydraulic model tests were carried out to confirm the stability of armor units and to obtain the empirical formulas for the estimation of the damage degree of the armor units in storms. The optimization procedures are presented by showing how to determine the optimum size of armor units which cover the front face of a caisson. The design method was applied to the selection of the optimum armor stone for the revetment with slope and terrace to confirm its applicability to a practical problem. The empirical formulas for the estimation of armor damage are obtained for the terrace and the slope separately because the damages of the armor units are characterized by the quite different damage features on the terrace and on the slope. The estimation of the life cycle costs for the armor stones of 1, 2, 3 and 4 tons and X-concrete block of 4 tons concludes that the armor stone of 2t becomes optimum because of its minimum LCC, though the initial construction cost is minimum for the armor stone of 1 ton.