Abstract Manager

Constructed in 1967 as part of the Mactaquac Hydroelectric Dam near Fredericton, New Brunswick; the inlet channel bridge carries two lanes of traffic over the Saint John River adjacent the dam’s intake structure. The NB Power owned diversion sluiceway forms the south abutment while the remaining bridge is owned by the New Brunswick Department of Transportation and Infrastructure. The seven span superstructure is comprised of simply supported prestressed girders and a concrete deck. The six hammerhead piers are in 18 m deep water.  A condition assessment was completed in 2019 which included a visual inspection, underwater inspection, ground penetrating radar survey, a materials testing program, and  an evlaution of the superstructure The resulting renewal strategy includes: replacement of the deck overhang and barriers, partial depth deck replacement with a thicker deck and integral concrete wearing surface, jacking to replace the bearings, strengthening of the hammerheads, repairing the defects associated with alaki aggregate reactivity expansion of the pier shafts, and elimination of the deck joints by converting the simple spans into three continuous spans with a semi-integral conversion of the north abutment.  This paper reviews the challenges in design including: eliminating deck joints, smoothing excessive camber and enhancing the rideability of the bridge, using externally bonded carbon fiber reinforced polymer to strengthen the pier hammerheads, the development of  an encapsulation system for the pier shafts in deep water, and the development  of a jacking systems for bearing replacement at skewed substructure elements.  Constrution began in November of 2022 and the paper will discuss some of the construction challenges faced to date and the solutions provided to overcome them.