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Approach Channel Bridge Rehabilitation

Abstract

Constructed in 1967 as part of the Mactaquac Hydroelectric Dam near Fredericton, New Brunswick; the
Approach 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 seven 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 deck survey, a material testing program, and an evaluation of the superstructure. The resulting renewal strategy includes replacement of the deck overhang and barriers, partial depth deck replacement with a thicker deck and exposed concrete wearing surface, jacking to replace the bearings, strengthening of the hammerheads, repairing the defects associated with alkali 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, and the development of an encapsulation system for the pier shafts in deep water. As the rehabilitation of this bridge approaches the mid-point of construction, this paper will present the status of the rehabilitation.

Conference Paper Details

Session title:
Transportation Structures
Author(s):
Young, Jason L.
Topics:
Structures
Year:
2024