The Herd Road bridge that crosses Richards Creek will be closed for approximately four months as North Cowichan carries out major upgrades on the structure.
North Cowichan’s council approved the $1.7-million project at its meeting on April 16, and the work is expected to commence later this year.
The bridge, which connects the communities of Crofton and Maple Bay to the Trans-Canada Highway, is on Herd Road, which is a major arterial road carrying more than 2,500 vehicles per day east and 2,500 vehicles west.
The concrete 37-year old bridge is deteriorating, putting the structural integrity of the girders that support the bridge deck at risk.
In addition, some other structural components, such as the pile cap and piles that support the bridge girders, need minor repairs.
John Dehoop, North Cowichan’s manager of infrastructure, said in a staff report that the deterioration of the bridge has been caused by the application of road salt in the winter months, which, while necessary, can compromise the integrity of the structure’s concrete deck.
He said that this will eventually lead to undermining the girders supporting the bridge deck.
“If salt-laden water is able to make its way through the bridge deck and migrate into the underlying structural components, the bridge structure itself may be damaged,” Dehoop said.
“This type of deterioration is typical for bridges of this age on Vancouver Island, and the proposed work is considered normal based on the age of this structure. Based on an assessment from 2024, if the upgrades and minor repairs are not done, more extensive and costly repairs will be necessary. Such work would also require the bridge to be closed for a longer duration.”
The project will address the deficiencies with the bridge deck and the underlying structure, as well as the bridge barriers that don’t currently meet the latest design standards.
Dehoop said the bridge work is being coordinated with the Bell McKinnon Road/Herd Road roundabout construction project to reduce inconvenience to the public as much as possible.
Seismic 2000 Construction Ltd.was awarded the contract with its bid of $1.7 million, which is well below the original estimate of $2.4 million for the bridge work.
Coun. Mike Caljouw asked if 37 years is the normal lifespan for a bridge like the one on Herd Road.
Clay Reitsma, North Cowichan’s director of engineering, said a bridge of this type typically has a lifespan of about 50 years before it has to be replaced.
“We’re at year 37 and it’s typical to have to do these kinds of repairs midstream so that we can extend the life of the bridge and get the 50 years out of it,” he said.
Coun. Bruce Findlay asked Reitsma what would the cost be if the bridge had to be entirely replaced.
“Don’t quote me on this, but based on some of the estimates we have on other bridges, we’re thinking about $7 million to $10 million,” Reitsma said.
“It’s really tough right now to predict these prices and, as each year goes by, I’m continually shocked by the increase in infrastructure costs.”
