한국해안·해양공학회논문집 (Journal of Korean Society of Coastal and Ocean Engineers)

  • 제22권3호
  • /
  • Pages.191-201
  • /
  • 2010
  • /
  • 1976-8192(pISSN)
  • /
  • 2288-2227(eISSN)
한국해안·해양공학회 (Korean Society of Coastal and Ocean Engineers)
권호 표지

경사식 방파제의 비용 최적화에 기초한 부분안전계수 및 목표파괴확률 산정

Estimation of Partial Safety Factors and Target Failure Probability Based on Cost Optimization of Rubble Mound Breakwaters

  • 김승우 (서울대학교 건설환경공학부) ;
  • 서경덕 (서울대학교 건설환경공학부) ;
  • Kim, Seung-Woo (Department of Civil and Environmental Engineering, Seoul National University) ;
  • Suh, Kyung-Duck (Department of Civil and Environmental Engineering, Seoul National University) ;
  • Burcharth, Hans F. (Aalborg University, Department of Civil Engineering)
  • 투고 : 2010.04.07
  • 심사 : 2010.06.22
  • 발행 : 2010.06.30
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초록

방파제는 인명 피해의 우려가 적은 구조물이기 때문에 주로 비용 최적화를 고려하여 설계한다. 하지만 대부분의 국내 방파제는 비용최적설계를 고려하지 않았다. 본 연구에서는 비용최적설계를 국내의 경사식 방파제에 적용하여 최적설계중량과 목표파괴확률 그리고 부분안전계수를 산정하였다. 사용한 방법은 PIANC Working Group 47의 Hans F. Burcharth and John D. Sorensen에 의해 개발된 것이다. 최적재현기간은 많은 경우에 50년으로 계산되었고 실질이자율이 높을 경우에 100년으로도 계산되었다. 최적재현기간에 해당하는 파괴확률과 기존 구조물의 신뢰성 해석에서 얻은 파괴확률을 사용하여 목표파괴확률을 제안하였다. 국내 설계기준인 초기한계상태의 최종적인 목표파괴확률은 약 60%이며 이에 상응하는 전체안전계수는 1.09이다. 이는 현행 설계법보다 9% 큰 공칭직경과 30% 큰 설계중량을 요구한다. 또한 비용최적설계를 고려한 부분안전계수를 산정하여 비용을 고려하지 않는 Level 2의 부분안전계수와 비교하였고 목표파괴확률이 40% 미만일 때 두 방법이 비교적 잘 일치함을 보였다.

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

키워드

참고문헌

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