Utility Pipe Crossing & Pedestrian Bridge
The Town of Banff is pleased to announce the completion of the utility pipe crossing and pedestrian bridge. While flooding delayed the bridge opening event, the bridge itself was not damaged from high water. The bridge opened July 2, 2013, three months ahead of schedule.
Some Facts About The Bridge
- The request for proposal explaining the project requirements was close to 400 pages long. Seven design-build tenders were received.
- The project was designed with the dual primary goals of replacing sanitary lines running under the Bow River and providing a pedestrian bridge. Replacing the sanitary lines by excavation or drilling would have involved additional costs and environmental impacts over the solution to secure the pipes to the bridge. By combining the projects, environmental impacts were greatly reduced and cost savings on the pipe replacement portion could be directed towards the bridge portion. By combining the projects it was possible to save more than $2 million on the total of the two budgets.
- A computer generated model of the entire structure was built and developed during the construction process. The model was able to accurately predict, within millimetres, the deflection of the bridge sections as the central keystone piece was lowered into place. Design and geometry modeling was done using the latest parametric 3D software.
- Piles were drilled rather than hammered in place to significantly reduce noise during construction. A steel sleeve was pushed into the ground and the centre drilled out. This process was repeated until the design depth was reached. Reinforcing steel was then placed into the empty sleeve and the sleeve was then extracted while the hole was being filled with concrete —leaving a 15-metre reinforced concrete pile in place.
- The glulam beams were fabricated in Oregon, shipped to Vancouver for milling and then shipped to site in three 40 metre loads. The beams are cantilevered towards the centre of the bridge with central piers taking the downward loads while piles at the abutments resist upward forces.
- The bridge was assembled on the river banks to minimize instream interference. A 500 ton crane was used to lift the three bridge sections in place, in March 2013. High-density poly ethylene pipe was welded together on the south side of the river and winched into place.
- The bridge deck has a maximum 5 per cent grade to maintain a low profile and assist with accessibility while maintaining clearance over the 1 to100 flood event elevation.
- Wood decking was selected to allow drainage and reduce build-up of snow and ice in the winter. The 113 timber deck panels are removable for easy access to the pipes running underneath them, and can be replaced in as required in the future.
- The bridge won a prestigious, international award from The Institution of Structural Engineers on Friday, November 14. Banff took first place in the pedestrian bridge category at a ceremony in London, England.
Project Description - An Overview
Aging sewer pipes, installed some time before 1968, carry all sanitary waste from the north side of the town under the Bow River from the south end of Muskrat Street to Glen Avenue. An investigation in late 2010 showed they needed to be replaced as soon as possible.
Several replacement methods were analyzed, and the solution of raising the pipes over the river, attached to a pedestrian bridge was approved by Council.
- Read the project updates
The total approved budget for the project is $6.806 million. The raised pipe/pedestrian bridge is eligible for a $370,000 transportation grant.
Approvals & Communication
Council first considered the sewer pipe replacement/pedestrian bridge concept on May 9, 2011, approved it on July 18, 2011, and again on December 14 with the approval of the 2012 to 2021 capital plan. On January 23, 2012 Council authorized staff to proceed with the design-build proposal supplied by StructureCraft Incorporated. After the April 10, 2012 briefing on a further investigation of direct drilling (trenchless option), in response to requests from a group of residents, Council indicated they preferred to proceed with the raised pipes/pedestrian bridge option.
Approval from three federal agencies (Parks Canada / CEAA, Transportation Canada (Navigable Waters) and Department of Fisheries and Oceans was secured for the raised sewer pipe crossing/pedestrian bridge project in early September 2012.
Construction began in mid-October.
Design features include low-rise span to protect views, wood and stone construction, minimal change to trail alignment and grade and low lighting. In case of emergencies on the south side of Banff, the bridge can accommodate an ambulance or a rescue truck, though not a fire truck loaded with water.
StructureCraft’s previous projects include the wood wave ceiling in the Richmond Olympic Oval and Princeton’s pedestrian Bridge of Dreams.
Connecting to the Community Plan
A pedestrian bridge meets many of the goals in the Banff Community Plan. It encourages and complements walking and cycling, which reduces greenhouse gas emissions; encourages active living; enhances the resident and visitor experience and amenity offerings; and is a reinvestment in vital infrastructure.