Design Of Vertical Breakwaters Research Articles

직립방파제의 케이슨 활동에 대한 최초통과확률법의 허용기준 산정

Probabilistic design methods can consider uncertainties of design variables and are widely used in the design of vertical breakwaters. The probabilistic design methods include a partial safety factor method, reliability-based design method, and performance-based design method. Especially the performance-based design method calculates the accumulated sliding distance during the lifetime of the breakwater or during a design storm. Recently a time-dependent performance-based design method has been developed based on the first-passage probability of individual sliding distance during a design storm. However, because the allowable criteria in the first-passage probability method are not established, the stability of structures cannot be quantitatively evaluated. In this study, the allowable first-passage probabilities for two limit states are proposed by calculating the first-passage probabilities for the cross-sections designed with various water depths and characteristics of extreme wave height distributions. The allowable first-passage probabilities are proposed as 5% and 1%, respectively, for the repairable limit state (allowable individual sliding distance of 0.03 m) and ultimate limit state (allowable individual sliding distance of 0.1 m). The proposed criteria are applied to the evaluation of the effect of wave-height increase due to climate change on the stability of the breakwater. 핵심용어: vertical breakwater, first-passage probability method, allowable first-passage probability, probabilistic design method, ì§ë¦½ë°©íŒŒì œ, ìµœì´ˆí†µê³¼í™•ë¥ ë²•, í—ˆìš©ìµœì´ˆí†µê³¼í™•ë¥ , í™•ë¥ ë¡ ì  설계법

Safety and Design of Vertical Breakwaters

The design of the breakwaters based on the current design manual in Hong Kong uses the overall safety factor approach. This approach, in general, does not provide a safety consistent design, and lacks the invariant property by using different definitions for load effects and resistance Identified through the rewriting of equilibrium equations. This study is focused on the selection of the design format to be used far designing vertical breakwaters subjeded to wave loading. The required caisson width of a vertical breakwater is evaluated using Coda’s formulas and different definitions of the overall safety factor. Also simple probabilistic analysis is carried out. The numerical results show that one should treat the wave induced load effects consistently in order to provide a more safety consistent design. Further, it is Indicated that the overall safety factor format in the current design manual for designing breakwaters can be modified into the so-called partial safety factor format. This modification do...

Design and construction of caisson breakwaters — the Japanese experience

The history of breakwater construction in Japan is reviewed and present design methods of vertical breakwaters are discussed in terms of wave forces and breakwater stability. Current design techniques of vertical breakwaters in Japan are the culmination of many years of experiences and practical research in this field. The Goda formula, which accurately predicts the design wave forces under most conditions of vertical breakwaters, is an excellent aid in the design of the breakwaters. Under certain conditions, excessive impulsive forces due to the action of breaking waves are exerted on the upright section. Such conditions must be minimized in the design of vertical breakwaters, and the adoption of vertical breakwaters covered with wave dissipating concrete blocks or the wave dissipating caisson breakwaters offer potential solutions of this problem. The bearing capacity of rubble mound foundation and the stability of armor units are also discussed.