Dicks Brook Bridge Replacement Approach
Location: Gros Morne, NL, Canada
Client: Parks Canada
Duration: 2014
Key Staff: Michael MacDonald, Tim Jordan, Cory Baker
Project Description
In 2014, Gros Morne National Park began the process of replacing the Dick’s Brook Bridge. This would be one of the first in a series of bridge replacements required by the famous park.
Harbourside’s Role
Harbourside Transportation Consultants completed the design of the vertical and horizontal alignments, from initial concept layouts through to detailed design and tender for the new approaches to the Dicks Brook Bridge Replacement.
The alignment options developed conformed to the requirement that the bridge and realigned section of highway needed to conform to an RCU 80 cross section. A modified section was developed for use for Gros Morne projects. This standard assembly was used for highway realignment at Baker’s Brook. The revised typical section provides safety and comfort for the roadway.
Two main horizontal alignment/bridge location alternatives were developed. Within each of the two main alternatives, higher design speeds were investigated, including 90 km/hr and 100 km/hr. These higher design speeds resulted in excessive amounts of earthworks (both filling and cutting) to achieve the shallower vertical sag curve profiles required and are not practical. For completeness, vertical profiles for 80 km/hr, 90 km/hr and 100 km/hr were included.
A temporary detour bridge alignment and a permanent bridge alignment to the north of the existing structure were investigated. This was in addition to the two options presented to the south of the existing structure. However, with the extensive rock cuts that would be required for these options, they were ruled out as being impractical.
Each of the requirements/obstacles was handled through careful planning by both Harbourside and PCA throughout design and through the creation of innovative, complete and accurate drawings and technical specifications.
Unique Challenges
A major requirement of the Dick’s Brook Bridge Replacement Project was the need to maintain two lanes of uninterrupted traffic throughout construction. This requirement influenced the alignment options developed, the bridge design options, the global phasing plan and the overall project budget. The constrained site with close proximity to the rock road cuts North and South of the structure and the skew of Dick’s Brook through the site and the local topography also influenced global phasing plans by mandating that the on-site detour and the new bridge structure be located adjacent to each other so as to limit the overall project footprint and prevent the need for extensive rock cutting.
Social Impact
The Dick’s Brook bridge marked the first of several bridge replacement projects in Gros Morne. This renewal of infrastructure ensures that travel through Newfoundland’s most famous park is kept safe for years to come. Using detailed design, and thorough evaluation, the approach to the new bridge is modernized and compliant to TAC guidelines.