Temporary bridge permits critical access during construction

Bolton, Ontario — Acrow Bridge, an international bridge engineering and supply company, furnished a modular steel panel bridge being used during replacement of the Montroyal Bridge over Mosquito Creek in the District of North Vancouver in British Columbia. The old structure was a 60-year-old timber bridge which was both under-capacity and at the end of its useful life.

Because the existing bridge was in close proximity to a fire station, it was critical that the detour structure be in place before demolition began in order to provide continuous passage for emergency vehicles. In addition, the route is heavily traveled by commuters.

The rented two-lane TL24 structure from Acrow is 130 feet long by 24 feet wide curb to curb, with guard rails and a 4.9-foot sidewalk.

“The Acrow structure was chosen over other temporary bridge options due to its lightweight modular components, allowing for staged installation that otherwise would have presented many challenges with a beam structure,” said Lyle Johnson, Manager of Field Operations for Eurovia BC. “The bearing to finished deck clearance at each end of Bridge minimized the excavation required for foundation installation.”

The launching and erection of the bridge posed numerous challenges. Because no room was available to stage components onsite, the Acrow components were delivered to a laydown area 2.5 miles from the site and brought to the work zone as needed. The build area for the Acrow detour bridge was limited to 40 feet by 32 feet on the west approach. The bridge was erected on rollers, with additional rollers on top of a temporary launching pier necessary for ease of erection and a safe launch.

For the final launch, a large crane positioned on the east approach was attached to the east end of the bridge. The bridge was moved to final position and held 2 meters above the East Bearings while the temporary pier was removed. The bridge was then lowered and set on both abutment bearings.

“We are pleased to have been involved in this important job,” said Ken Scott, President of Acrow Limited. “It was particularly gratifying to have helped overcome the challenges of this difficult installation and assist with a solution for Eurovia BC and the Stakeholders.”

The owner of the project is the Corporation of the District of North Vancouver, BC. The contractor is Eurovia BC Inc. which selected the Acrow bridge for the job. The design engineer for the detour for Eurovia was All-Span Engineering & Construction Ltd. and McElhanney Consulting Services Ltd. The design engineer for the owners was WSP Canada Inc.

The Acrow bridge installation was started on June 21 and completed in less than three weeks. It is anticipated that the temporary bridge will be in place throughout the construction, which is scheduled for completion in summer 2018.