Portfolio Category: <span>Bridges</span>

This 12 span continuous, 2 lane, 342.5 m precast girder bridge crosses the Little Tracadie River estuary and was constructed in 2001.

Geotechnical considerations required the removal of unsuitable material and the construction of a new approach fill at the north end of the structure. The material to be excavated was below the fluctuating tidal water level. Shot rock was used to raise the approach fill above the tidal water level to the underside of the north abutment. The excavation of the unsuitable material was completed in a silt boom enclosure to conform with the environmental control requirements for the site.

The bridge superstructure consists of a concrete deck supported by NBDOT Type 1 precast, prestressed concrete reinforced girders. The superstructure was supported on economical pipe pile bents in an aggressive marine environment. At pier 1 and 11, H-pile leads were required to ensure anchorage into the bedrock. A cathodic protection system was developed to extend the life of the steel pipe piles considering the harsh marine environment.

This 8 span continuous, 4 lane, 226 m long precast concrete girder bridge crosses Bathurst Harbour and was constructed in 1997 to replace an existing bridge. The 28± m span configurations avoided interference with the existing piers. The bridge girders were constructed using precast prestressed concrete NBDOT Type 1 beams.

The prestressed concrete girder structure was supported on economical pipe piled bents in an aggressive marine environment. A cathodic protection system was developed to extend the life of the steel pipe piles considering the harsh marine environment.

In order to reduce the substructure costs, pile load testing was performed early in the design.

The bridge has a 2 m wide pedestrian sidewalk on the west side with a custom aluminum pedestrian railing and light standards.

This $10.5±M, 6 span continuous, 2 lane, 355 m long steel girder bridge was part of the Longs Creek – Grand Falls Trans Canada Highway project constructed by Brunway Group in 2005 – 07. The structure was constructed with 62.5 m – 68 m interior spans with 47 m and 50 m end spans.

The Meduxnekeag River at the crossing site is a medium size, fast flowing stream bounded on the south by a considerable expanse of flat low lying grassy river bank. Beyond the river’s flood plain area, wooded river banks slope steeply to a height of 30 m above the level of the valley below.

The bridge was constructed to replace an existing bridge that had been constructed in 1960. The spans and pier locations of the new bridge were selected to minimize interaction with the existing bridge’s deep substructure units.

The bridge girders were constructed using unpainted, weathering steel protected from spray and bridge deck run off by a waterproof membrane and concrete deck slab cantilevering well beyond the bridge’s steel spandrel girders.

The use of expansion joints was minimized with only two finger plate expansion joints located at the bridge abutments. Pot bearing assemblies were used to support the bridge superstructure.

Pier footings were placed below the existing gravel stream bed and supported either on bedrock or on driven steel H piling. As such, minimal amounts of moderately sized pier scour protection were required.

These two 4 span continuous, 2 lane, 157 m long prestressed concrete girder bridges were part of the Fredericton – Moncton Trans Canada Highway project constructed by MRDC in 2000. The superstructures consist of 4 span pre-cast, pre-stressed 1900 mm deep bulb tees. These bridges replaced a 1960s era two lane highway bridge. Technical challenges included designing the substructures for a very soft and deep over burden requiring monitored pre-loading, tied-back abutments and sleeved piles. In addition, the river piers had unique pipe piled elevated bath tub type pier footings which precluded the use of more expensive deep seated steel sheet piled cofferdams.