As a preparation of a design standard regarding road facilities, such as cantilever columns for traffic lights, optimum design and risk assessment for foundation of street lights on highways are proposed. The preliminary evaluation of optimization with reliability assessment resultantly makes it possible to reduce not only the duration of construction but the cost of construction as well. Ultimate limit states and constraints functions are selected for the sliding, overturning and settlement of the foundation under external loads from super and sub-structures itself. An example foundation under the super structure of height 12m, is optimized as 30% decreased embedded depth of foundation, in which as increasing the depth of embedded connection parts, the necessary depth of foundation is deceased. However, the optimum depths and the reliability indices are sensitively dependent with earth properties and dimensions of foundation.

1. 서 론
 2. 프리캐스트 하부구조의 최적설계
  2.1 최적설계
  2.2 극한한계상태식과 최적설계 모델링
 3. 지주구조물 기초의 최적설계
  3.1 프리캐스트 상부구조의 설계
  3.2 프리캐스트 기초구조의 최적설계
  3.3 지주구조물 기초의 한계상태 신뢰성평가
 4. 결론 및 향후 연구방향
 REFERENCES