This professional services agreement is for the final design and bidding of the Gurley Overpass Deck repairs. Preliminary design and mapping of the deck delamination was performed during the 2017 Barrier Rehab project. $20,556.18 was expended on the preliminary design under that project's contract.
The Bridge Deck Rehab construction scope will include milling the entire deck surface, spot removal of remaining delaminated and deteriorated deck concrete, a silica fume concrete overlay of the bridge deck, and an epoxy overlay. The epoxy overlay will provide surface wear resistance, protect the deck from moisture and salt infiltration, and provide frictional resistance equivalent to a high friction surface treatment.
The deck was last restored in 2010 with a surface mill, delaminated concrete removal and a silica fume concrete overlay. The main objective of that project was to replace failed bridge bearings on the north span and to replace the failed expansion device at the center of the deck. The previous deck overlay was not followed by an epoxy overlay. In 2013, numerous cracks were observed on the deck. The deck was sealed with a methacrylate "healer/sealer" to reduce moisture and salt infiltration as well as to restore some structural capacity to the joints. In 2015, additional work was done to restore water damage to the north abutment and to Pier #5, located beneath the mid structure expansion device. While trying to address wear of the deck surface and reduced surface friction, it was discovered that the deck is again delaminating. During the 2017 barrier rehabilitation work, a spall developed on the north span and led to the chain-dragging of the deck to identify the scope of the delaminated concrete. |