Effect of Alkali-Silica Reaction/Delayed Ettringite Formation Damage on Behavior of Deeply Embedded Anchor Bolts

In Texas, many drilled-shaft concrete foundations of high-mast illumination poles (HMIPs) constructed in the late 1980s were found to have premature concrete deterioration due to alkali-silica reaction (ASR) and delayed ettringite formation (DEF). To investigate the effect of ASR/DEF damage on the structural performance of deeply embedded bolts anchoring the pole to the HMIP foundation, six full-scale field tests were conducted in Houston, TX. In this study, two types of drilled-shaft foundations were examined: drilled shafts with 16 anchor bolts supporting 150 ft (46 m) poles, and shafts with 20 anchor bolts supporting 175 ft (53 m) poles. One of the tested drilled shafts with 20 anchor bolts was repaired by wrapping it with carbon fiber-reinforced polymer (CFRP) sheets. Failure modes and related load-transfer mechanisms were investigated and design refinements were developed to current ACI requirements for these deep anchor bolts. [PUBLICATION ABSTRACT]