Type: Center Bearing Highway Swing Span
Location: Port Severn, ON
Owner: Parks Canada
Stafford Bandlow Engineering personnel provided the mechanical and electrical engineering for the replacement of all machinery and electrical power control systems for this heritage center bearing swing span bridge. Services included a scoping condition survey and inspection, preparation of plans, specifications and cost estimates for all machinery, new electric service and bridge and vehicular traffic control systems, as well as provision of construction testing and start up services.
The intent of the project was to return this non-functional 1915 designed bridge back to a serviceable condition with significant upgrades to the original live load capacity without altering the appearance of the structure. The Owners preference was for the design to utilize hydraulic slewing cylinders similar to the existing machinery which was installed circa 1979.
As part of the scoping study it was found that the end lift machinery and span drive machinery did not meet existing code requirements and necessary upgrades to conform to current codes were incorporated into the design. The bridge superstructure was found to be in such poor condition that complete replacement was necessary to meet the objectives of increasing the bridge live load capacity. Analysis also indicated that the existing end support casters and center pintle were not adequate for the proposed increased live load. New designs were provided for each mechanical element with the intent of upgrading the capacity of the components while maintaining the basic appearance and functionality of the structure, which was critical to meeting the heritage objectives of the project. The design provided complete details for all span drive machinery, center bearing machinery, end support casters, balance wheels and rail, end lift and wedge machinery, hydraulic power units and electrical power and control systems. System reliability and longevity under minimal maintenance was a large consideration in the selection of the span drive and span support components. The electrical systems design included re-routing the existing electric utility to the bridge, designing and specifying a new motor control center and a semi-automatic bridge control system, and developing a code conforming vehicular traffic control system for this single lane highway bridge.
Construction Services for this project included shop drawing review, source inspection of machinery, supervision of machinery installation, periodic inspections of ongoing electrical installation work, and start up and testing of the completed installation.