Anchor Bolt Behavior in ASR/DEF-Damaged Drilled Shafts

The primary objective of this research is to evaluate the effect of Alkali-Silica Reaction (ASR) and Delayed Ettringite Formation (DEF) on the structural performance of High Mast Illumination Pole (HMIP) foundations and if needed, to recommend a possible retrofitting method to strengthen them and prevent further damage. To achieve this goal, six full-scale field tests were conducted in the Houston area. Two types of drilled shafts were examined: 16-anchor drilled shafts supporting 150-ft high HMIPs; and 20-anchor drilled shafts supporting 175-ft high HMIPs. One of the 20-anchor drilled shafts was repaired by wrapping with Carbon Fiber-Reinforced Polymer (CFRP) laminate. Observed performance under field tests was also evaluated in the context of the design wind loads of the AASHTO Specifications (2001) and ASCE 7-05 (2005). Failure modes and the related load-transfer mechanisms were investigated and some design recommendations were suggested for better design of drilled shafts.