As a preparation of a design standard regarding road facilities in terms of reliability based optimum design examples, such as cantilever columns for traffic lights, optimum design in deterministic and probabilistic ways for the foundation of traffic lights poles are proposed. Most of the previous study have focused on the foundation surrounded by cohesionless soil. However, the design would be governed by risky condition. Therefore the resistance by clay-soil is investigated compared with other design specifications. In deterministic optimization, GRG method is applied. It is found that both geometries of deep and shallow foundation provides optimum values. The resistance of cohesive soil is selected to represent the ultimate limit states, in terms of sliding, overturning and bearing pressures from super structures to the foundation under external loads. Example foundations with varying height of columns for traffic lights are optimized about 30% decreased embedded depth of foundation. The optimum coefficients of resistant and load factors may need to be developed with design load combinations in order to prepare design specifications as the next step.

1. 서 론
 2. 매립깊이의 설계 시방기준비교
  2.1 유럽(EN 40-2)시방서의 규정비교
  2.2 미국 AASHTO-LTS6 시방서의 규정비교
 3. 최적설계
  3.1 하중과 저항
  3.2 설계기법
 4. 신뢰성기반 최적설계
  4.1 목표신뢰도의 결정과 설계
  4.2 극한한계상태식과 최적설계 모델링
  4.3 프리캐스트 기초구조의 확정론적 최적설계
  4.4 프리캐스트 기초구조의 신뢰성기반 최적설계
  4.5 프리캐스트 기초구조의 신뢰성 민감도
 5. 결론 및 향후 연구방향
 REFERENCES

• 조태준(대진대학교 건설시스템공학과 부교수) | Cho, Taejun
• 박신전(㈜케이엠티엘 기술연구소 이사) | Park, Sinzeon Corresponding author