Mossington Bridge safety modifications

The following briefly summarizes the project:

• In September 2023, the safety assessment study of the Mossington Bridge was completed.
• The safety assessment study recommended the following measures be implemented to deter hazardous behaviour:
  • Enhanced signage and safety campaign
  • Security cameras
  • Bylaw enforcement
  • Physical barrier
• In October 2023, staff proceeded with implementation of the recommendations of the safety assessment.
• In February 2024, the Town retained the services of Doug Dixon and Associates (DDA) – a highly qualified bridge design engineer – to evaluate options for a physical safety barrier system and complete the detailed design.  In the following months, options analysis, multi-criteria analysis and structural feasibility culminated in the options proposal via the preliminary design report.
• In April 2024, the preliminary design report was discussed in two subsequent workshops, resulting in a combined proposal of improving the fence so it could not be climbed (remove lattice and replace with 2.4m fence) and installing the shrouds. This concept was the recommended approach.
• In May 2024, the preliminary design report results and recommended approach were reviewed:
  • The evaluation of several options was presented including large acrylic (i.e. see-through) panels enclosing the sides of the bridge; localized acrylic plates mounted on the structural frame members to cover hand-holds; installation of net/fencing mesh enclosing the sides of the bridge; taller (2.4m) steel railing and steel plates mounted on the structural frame members to cover hand-holds.
  • The use of acrylic panels was found to be unfeasible as the resultant vertical and wind loads would exceed the structural capacity of the bridge.
  • The use of acrylic plates and net/fencing mesh were determined to be inconsistent with historical materials of construction of the bridge and these approaches were also found to be less effective in deterring hazardous behaviour.
  • The 2.4m steel railing and steel cover plates approach was recommended as the most effective option that would also be in keeping with the cultural heritage of the Mossington Bridge.
  • Staff were authorized to proceed with detailed design of the 2.4m steel railing and steel cover plates barrier system; and to preserve confidentiality of the project, identify a well-qualified contractor to negotiate for fabrication and installation of the safety modifications, in line with the procurement policy.
• In July 2024, staff retained LHC Heritage Planning and Archaeology (LHC), to prepare a Heritage Impact Memo and Letter assessing the cultural impacts of the proposed safety modifications to the bridge. LHC’s assessment concluded that the proposed modifications to the bridge are consistent with good heritage conservation practices.
• In August 2024, staff engaged with Bau Meister Mechanical Fabrications Ltd. partnered with H.T.E Ltd. These firms came highly recommended and capable, having been previously contracted by several government agencies at all levels, and demonstrated the necessary financial, technical and operational capacity to deliver a project such as this. Following a fulsome reference check, and following guidance under the Town’s procurement Policy, a firm quotation for fabrication and installation of the safety modifications to the Mossington Bridge was obtained that met all specifications, both technical and administrative. The Town’s bridge design engineer for the project (DDA) independently reviewed HTE/Bau Meister’s quotation and confirmed the pricing offered as competitive and providing the Town with good value.
• In September 2024, staff confirmed the final design for the safety barrier system and the results of LHC’s cultural heritage review. The overview of actions, implementation timing of the safety modifications, financial implications and contract execution were reviewed and approved to proceed with advanced public notice.
• In October 2024, traffic control preparation and curb repairs took place.
• In November 2024:
  • Council Report OID-2024-0018 Mossington Bridge Study Results and Implementation Plan was released providing an update on the project.
  • Public notices were posted, traffic management measures were put in place.
  • The Mossington Bridge was temporarily closed on Nov. 19, 2024.
  • Following the installation of the safety barrier system, signage and security cameras, the bridge was then reopened.

In December 2024, as built drawings were submitted to the Town.

• Appendix A: Mossington Bridge - Final Draft Report, Safe Roads Engineering, July 27, 2023 (Safety Assessment Study)
• Appendix B: Mossington Bridge Modifications, Doug Dixon and Associates, April 2024 (Preliminary Design)
• Appendix C: Cultural Heritage Impact Opinion Memorandum, Mossington Bridge, LHC Heritage Planning and Archaeology, July 12, 2024
• Appendix D: Letter of Opinion Mossington Bridge Modifications Cultural Heritage Review, LHC Heritage Planning and Archaeology, July 12, 2024
• Appendix E: Mossington Bridge Modifications, Detailed Design Drawings, Doug Dixon and Associates, July 2024
• Council Report OID-2024-0018 

Due to the long history of hazardous behaviour that has been associated with the Mossington Bridge, it was determined there was a safety risk and action was needed to deter hazardous behaviour. The safety modifications that have been installed are the result of this.

While there may be a visual impression of the bridge feeling more ‘closed in’ due to the increased height and spacing of the new barrier rails, there has been no change to the lateral clearance between the existing curbs on the bridge deck and only a negligible change to the inside clearance between the rails above the deck. 

The Mossington Bridge is designated under Part IV Section 29 of the Ontario Heritage Act (OHA) through Bylaw 2002-0015. The Town retained the services of LHC Heritage Planning and Archaeology to provide a formal opinion from a heritage conservation perspective regarding the Town’s plans to implement safety modifications on the Mossington Bridge. LHC confirmed the proposed bridge modifications constructed using steel, are generally consistent and compliant with good heritage conservation practices. 

As one example of the Town’s commitment to preserving the heritage value of the Mossington Bridge, given the unique and widely recognizable colour of the “Blue Bridge,” staff took samples of paint chips and had a custom colour paint match prepared to ensure the new steel components would exactly match the existing bridge.