The number of aged bridges is increasing so that bridges over 30 years old account for about 11% of all bridges. Consequently, the development of a seismic performance evaluation method that considers the effects of ageing is essential for a seismic retrofitting process for improvement of the seismic safety of existing old bridges. Assessment of the damage situation of bridges after the recent earthquakes in Korea has been limited to the bearings, anchor, and concrete mortar on piers. The purpose of this study is to evaluate the seismic responses of PSC box girder bridges by considering the ageing effect of rubber bearings (RBs) and lead-rubber bearings (LRBs). The modification factor proposed by AASHTO is used to take into account the ageing effect in the bearings. PSC box girder bridges with RBs and LRBs were 3D modeled and analyzed with the OpenSEES program. In order to evaluate the ageing effect of RBs and LRBs, 40 near fault and 40 far field records were used as the input earthquakes. When considering the effect of ageing, the displacement responses and shear forces of bridge bearings (RBs and LRBs) were found to increase mostly under the analytical conditions. It was shown that the effect of ageing is greater in the case of RBs than in the case of LRBs.

ABSTRACT
1. 서 론
2. PSC-Box 거더 교량의 지진해석
    2.1 교량 모델링
    2.2 노후화를 고려한 교량받침 모델링
    2.3 입력지진의 특성
3. 교량받침의 노후화를 고려한 지진응답의 비교
4. 결 론
REFERENCES

• 정연희(강원대학교 건축·토목·환경공학부 토목공학과) | Jeong Yeon Hui (Department of Civil Engineering, Kangwon National University)
• 송종걸(강원대학교 건축·토목·환경공학부 토목공학과) | Song Jong-Keol (Department of Civil Engineering, Kangwon National University)
• 신수봉(인하대학교 사회인프라공학과) | Shin Soobong (Department of Civil Engineering, Inha University) Corresponding author