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A landmark lifting bridge that stands in the central part of the LaSalle Causeway in Kingston, Ont. is set to be rebuilt so it can remain in service for another three decades.

Landform Civil Infrastructures Inc., a Hamilton-based heavy civil construction firm that specializes in bridge reconstruction and rehabilitation, will start work this fall on the green metal structure.

The company has been awarded an $8.8-million contract to strengthen and replace various components of the crossing — known as a bascule bridge — at the causeway near the mouth of the Great Cataraqui River.

Crews are scheduled to start work in November on strengthening the structure and replacing various components.

The steel deck grating and supporting stringers are to be replaced along with deteriorated concrete on the counterweight. The contractors will also strengthen supporting steel truss components at the main trunnions.

Trunnion is a French word for “pivot point.” Trunnions are a key operational component of the bridge that require regular overhauls.

The counterweights allow the bridge to be raised and lowered. Earlier inspections of the counterweight system indicated repairs and renovations were needed to ensure the safety of pedestrians and public and commercial traffic that use the bridge.

The project is expected to extend the service life of each of the components by another 30 years, improving the condition and operation of the bridge.

The work will take approximately 18 months, with the project scheduled to be completed by May 2025.

Design and engineering consultant on the project is Parsons Inc. of Ottawa.

The causeway, which was opened in 1917, links downtown Kingston to Pittsburgh Township and is part of Highway 2. It connects the city to suburbs in the east.

The causeway itself consists of three separate bridges and two wharfs.

Two of the bridges are fixed and located at each end of the causeway.

The bascule bridge spans the central channel.

Public Services and Procurement Minister Helena Jaczek recently announced the federal government is contributing the funds for the project.

“The bascule bridge is a vital link for the local community in Kingston,” she said.

“This contract is an important step in ensuring the bridge remains safe and operational, and continues to serve local and commercial traffic needs.”

On average, 23,000 vehicles a day cross the causeway in addition to cyclists and pedestrians.

To minimize disruptions, construction work on the bridge will take place during two periods in the off-season — from November 2023 to April 2024 and November 2024 to April 2025 — when the bridge is traditionally closed to marine traffic.

Although marine traffic will not be allowed under the bridge, the construction team will be making arrangements so pedestrians and cyclists will still be able to cross via a temporary sidewalk.

Plans to rehabilitate the bridge began in early 2021. As part of the planning, the project team consulted with the City of Kingston, marine-based businesses in the area, downtown business associations, the Royal Military College of Canada, provincial ministry of transportation and a number of federal authorities and departments with jurisdiction.

The bridge rehabilitation project was originally scheduled to begin in November 2022 but was delayed for a year because no responsive bids were received from the construction tender.

Public Services and Procurement Canada posted a new tender in February. The contract to Landform Inc. was announced in late June.

A virtual public information session is scheduled to be held in the coming months prior to the start of construction in order to provide an overview and more details for residents.

The bridge is of historical significance and, due to its proximity in the middle of the causeway separating the inner harbour from the river, it’s a recognizable local reference point.

The original structure on the causeway was a wooden toll bridge that was built in 1829 with a swing section to allow passage of boats. It was eventually replaced with the bascule bridge, a single-leaf Strauss heel-trunnion crossing designed by Joseph Strauss of the Strauss Bascule Bridge Co. of Chicago who designed the Golden Gate Bridge in San Francisco.

The bridge is one of the few examples in Canada of a Strauss heel-trunnion bascule bridge. They were common along railways but are now rare in Canada as many of them have been demolished.

The bridge is unique as a rocking truss that holds the counterweight and rotates around the trunnion has more angles and diagonals extending outwards than with a typical heel-trunnion bridge, giving it a more curved look. The top chord of the bascule leaf is also not parallel to the bottom chord.

Over the years, the bridge has undergone a series of renovations.

In 2010, an extensive rehabilitation was done, and 10 years later the mechanical systems were repaired to address deficiencies that impacted operations.

More work was done in 2021 to address fatigue issues in the steel structural truss and the following year concrete repairs were completed to address deficiencies on the road as well as structural issues.