Appendix A - Evaluation of Galvanized Reinforcing Steel in the Longbird Bridge, Bermuda

Abstract

This chapter presents an investigation intended to evaluate the performance and corrosion resistance of the galvanized reinforcing steel in the Longbird Bridge in Bermuda, built in 1952. For this purpose, two concrete cores were extracted and forwarded to Construction Technology Laboratories (CTL). These cores were nominally 5.5 in. (140mm) in diameter and 12 in. (300mm) and 6 in. (150 mm) long. Core No. 1 was taken horizontally into the bridge deck from an outer exposed formed surface, while Core No. 2 was taken vertically through a curb sidewalk component of the structure. Core procurement was done in the fall of 1994. This petrographic examination of concrete cores, determination of acid-soluble chloride contents, and the various metallurgical analyses of the galvanized coating were included in the investigation. The petrographic examination revealed the concrete to be in good condition with no evidence of progressive degradation. There is neither an evidence of corrosion of the reinforcing steel substrate beneath the galvanized coating nor cracks associated with steel that might reflect corrosion of the steel.