Assessments of Cracks in Hollow Prestressed Concrete Bridge Cylinder Piles

Some large river crossing bridges in Maryland are comprised of pile bents using large prestressed concrete cylindrical piles. Inspection of these bridges, above and below water, have identified cracks in these piles. This is concerning for several reasons. First, these piles are large and take large loads. There is little redundancy in this foundation system. Failure of one of these piles could have serious implication to the stability of the bridge. Second, because these piles are in deep water, possible methods of repair to date have proven difficult and costly. The intent of this research is to find an effective assessment measure of a prestressed concrete cylinder pile with cracks. In addition, when the assessment method determines the capacity of the pile has been compromised due to cracks, what are effective methods of repair and retrofit. Maryland has adopted several repair techniques and is familiar with installing pile jackets with grout as a protection scheme. However, Maryland Department of Transportation State Highway Administration (MDOT SHA) would like to know if there are coatings or some other means to provide better protection. The research will include: (1) literature review of existing research on this topic; (2) survey to state DOTs that use this pile type on a frequent basis to gather current practices; and (3) field testing of the recommended crack assessment method. The literature review and current practice synthesis should cover the methods/actions taken by other States to assess the piles condition, to repair defects, and to perform preservation actions, in order to manage and maintain these piles for a safe level of service.