Chapter 4 - Outline of design procedure

Abstract

The design procedure is usually divided into a preliminary (or conceptual) design phase and a detailed design phase. The objective of the preliminary design phase is to explore project's feasibility with respect to economy, technical performance, and societal and environmental impacts. This usually involves conceptual design of alternative LCS schemes. A preferred scheme is then selected for a detailed design that consists of optimizing the scheme with respect to impacts, structural performance, and costs. To establish necessary boundary conditions and hydrodynamic input, and to run such models is all together very costly and time consuming. Therefore, they are generally used only for finer tuning of larger schemes. In most cases, only more simple numerical models are used locally for short-term simulations. It follows that the uncertainty related to the long-term prediction of morphological response is large. The tools for a structural design are quite reliable formulae for the stability of various parts of the structures, and/or performance of model tests. The major part of the uncertainty of a structural response is related to the estimation of design wave climate and if scour is critical, to the local currents at the structures. Because the structure should preserve its shape for the whole project period and because repair cannot take place immediately after damage, it is a common practice in structural design to consider the most severe environmental conditions in structure lifetime.