Our partners won an award - Ontario Road Builders Association
Design Evolution
Some elements of the bridge design have evolved through various phases of the project: planning and design process (otherwise known as the Environmental Assessment); preliminary design and current design. Changes have been made in consultation with various federal departments and agencies and working with the Integrated Project Delivery team.
Changes have been made to the following three areas: main and approach spans, the high point of the bridge and; bridge piers.
Design changes were necessitated by the following considerations:
1. Respect for the natural environment and cultural heritage
- Reduce the overall in-water footprint of the bridge
- Minimize the visual impact on the Rideau Canal
2. Design optimization
- No need for structural arch
- Able to reduce navigation span
- Simple span with under arch design
- Minimize long-term operation and maintenance costs
3. Price certainty
- The risk associated with steel pricing and 2018/2019 steel tariffs
- Concrete girders for approach, spans – stable pricing
4. Accelerated construction techniques optimized
Weathering steel for the main span
Did you know that the steel used to build the main span of the Third Crossing is called weathering steel? Weathering steel is a type of steel alloy that forms a protective layer on its surface and is resistant to atmospheric corrosion. As a result, weathering steel forms a stable and protective coating that gives the steel a rust-like appearance after being exposed to weather.
The significant benefit of using weathering steel is the elimination of the need to paint the steel to provide corrosion protection. In addition, it also eliminates the expense and environmentally sensitive work to regularly re-paint the steel over its entire life.
Safety
- Railings, barriers, and lighting will be designed to ensure the safety of those travelling on or underneath the bridge.
- Concrete barriers separating the multi-use path from the traffic roads will be used.
- Lighting design will provide safe, effective illumination that is focused on the roadways, multi-use pathway and navigation channel.
Stormwater management
Stormwater management both on the bridge and at the approaches is an important aspect of bridge design, and something the City has heard is important to local residents. Stormwater management will entail several water treatment measures, including:
- Grassed swales for quality/quantity control of runoff
- Oil grit separators (e.g. stormceptors) for quality control at the outlet of swales
- Stormwater piping with rip rap protection conveying runoff from the approach and bridge to the enhanced grass swales
- Catch basins and sewers
Bridge Maintenance
Snow and ice on the bridge will be managed according to the City of Kingston’s Winter Operations Level of Service Policy. The Public Works department will strive to provide safe winter road and sidewalk conditions for vehicles/cyclists and pedestrian traffic. The City will apply pre-treatments in the form of Direct Liquid Application in advance of snowfall events to prevent and/or treat ice formation.
The bridge design will incorporate the following:
- The bridge deck, including shoulders adjacent to the vehicular lanes that will provide for temporary snow storage and drainage;
- Durable materials to withstand snowplow wear;
- No obstructions on the roadway or multi-use pathway to impede the efficient removal of snow from the bridge deck; and
- Multi-use pathway sloped towards the centre barrier to facilitate the flow of snowmelt to the deck drains.
