Fatigue Evaluation for Reinforced Concrete Box Culverts

Abstract

Prior research conducted on welded wire reinforcement and fatigue resistance has resulted in proposed changes to American Association of State Highway Officials (AASHTO) design standards for bridge superstructures that may be overly conservative for reinforced concrete box culverts. This paper describes an experimental program conducted to evaluate the fatigue effects on reinforced concrete (RC) box culverts, and whether the changes recommended for fatigue resistance were valid for box culverts. Two full-scale RC box culvert sections designed and manufactured according to ASTM C1577 were tested. The first specimen was 12 ft x 4 ft x 12 in. (3657.6 x 1219.2 x 304.8 mm), and the second was 7 ft x 4 ft x 8 in. (2133.6 x 1219.2 x 203.2 mm). Test results show a good distribution of the load resistance between the two reinforcement directions in box culvert sections. Fatigue effect on the flexural capacity of the RC box culvert sections was minimal. These findings indicate that the fatigue check for RC box culverts designed according to ASTM C1577 can be eliminated. This waiver of the fatigue requirements in box culvert design will appear in the next version of the AASHTO Load and Resistance Factor Design standards.