The Gardiner Expressway will need "significant rehabilitation" over the next decade, which will cost millions to complete and will leave Toronto drivers coping with unwanted delays.

Peter Crockett, the city’s executive director of technical services, said that the Gardiner is safe for use, despite a pair of incidents last week in which chunks of concrete fell from its underbelly.

"The Gardiner is safe, it’s structurally sound," Crockett told CBC News. "We obviously have an issue with respect to some fallen concrete, but we’re dealing with that as well."The pieces that fell were part of what is known as superficial "cover" concrete.

However, Crockett said that the Gardiner is simply at a point in its life when it needs some major repairs.

"We’re entering an era of a need for some significant rehabilitation over the next 10 years in the Gardiner," he said.

This year, the city will be conducting repairs along a stretch of the Gardiner between Jarvis and Bay streets, Crockett said.

"We’re doing some major rehabilitation work in there," he said.

"It’ll involve some ramp closures — the Jarvis off-ramp, eastbound on the Gardiner will be closed at some point over the course of the summer, as will the on-ramp from northbound Bay onto [the] eastbound Gardiner as well."

Crockett said those repairs could last as long as six weeks and could result in lane closures on Bay Street, York Street and Yonge Street, as well as lane closures on the Gardiner itself.

"We’re going to manage that as much as we can around the peak hours, so that we minimize the impact as much as we can," he said.

The CBC’s Jamie Strashin reported that the city will spend $150 million on repairs to the Gardiner over the next decade.

City staff gave an update to councillors Wednesday on the condition of the Gardiner and what the city is doing to maintain it.

Coun. Denzil Minnan-Wong, the chair of the public works committee, is looking at more thorough and frequent inspections for the Gardiner, which Crockett said is already inspected each year.

The inspections will involve "going up on the cranes and looking under and tapping on to the cement, just to make sure and double-check that the structure’s safe," Minnan-Wong told CBC News.

The update from city staff came after a week in which chunks of concrete fell off the Gardiner in two separate incidents. One piece of concrete fell from the underside of the overpass onto Lake Shore Boulevard near Lower Jarvis Street last Monday. Three days later, another piece fell from the underside of the Gardiner onto Parkside Drive near Lake Shore Boulevard West.

There were no injuries or damage to vehicles in either of the incidents.

Staff said pieces crumble after salt and water seep into the concrete and cause the steel rebar to corrode and expand. This expansion fractures the surrounding concrete.

Those fissures expand in the freeze and thaw cycles caused by the change of the seasons, which in turn results in crumbling concrete.

With files from the CBC's Jamie Strashin