The Michigan Department of Transportation has a large number of bridges that have hammerhead and cantilever concrete pier cap substructures that support the bridge superstructure.The bridge structures of the I-696 depressed Freeway in Detroit are an example where numerous hammerhead piers supporting both steel and concrete superstructures are used.Many hammerhead piers have developed diagonal cracks from the top of the pier column down through the cantilever section.The cracks are various lengths and widths and typically start at a bearing point at the top of the pier reflecting downward.Crack width was greater at the top of the pier than the termination point,which typically transitions to hairline.Rehabiliataion of three of these hammerhead piers required sealing the cracks with grout and epoxy injecting each crack.Then,a concrete wall was cast between the cantilever portion of the hammerhead pier and the shoulder of the highway below.Accessibility to the project and relatively low under clearance,made possible casting a concrete wall below the cantilever sections.
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