Anchor Bolt Projection

Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record. 

An illustration of such a realistic problem was the July 2006 failure of anchor bolts held in place by an epoxy adhesive that led to massive amounts of concrete to fall on motorists in the D Street portal of the Interstate 90 (1-90) connector tunnel in Boston, resulting in one death. The NTSB Highway Safety Board announced in July of 2007 that the cause of the failure was due to creep of the epoxy adhesive. The time from installation until failure was a number of years, perhaps as many as ten. Obtaining ten-year data in advance of a project is not realistic but perhaps well-defined creep to yield or rupture tests could have established a lower bound and given engineers a better understanding of how to make sure that such a failure would not occur. 

Lee, D. W., and J. E. Breen (1966), Factors Affecting Anchor Bolt Development, Research Report 88-lF, Project 3-5-65-88, Cooperative Highway Research Program with Texas Highway Department and U.S. Bureau of Public Roads, Center for Highway Research, University of Texas, Austin Austin, TX. 

A loose bolt type of fitting for the liner anchors would not be acceptable to liner designers because it would depend on a nut and washer to seal the preformed hole in the liner. Liner anchors penetrating and projecting from the liner face would not be acceptable either since the resultant thickness of liner around the perimeter of the preformed hole is only the thickness of the fillet weld to the anchor rod. The detail could be... 

---