On April 29, 2016, a portion of Canal Street in downtown New Orleans collapsed, forming a massive 600 square-foot sinkhole between Harrah’s Casino and the Shops at Canal Place.
The sinkhole was above a long-abandoned 700-foot-long, 98-foot-wide tunnel originally constructed as part of a plan to run an expressway along the Mississippi River.
To reduce the sinkhole’s impact on the local business community, tourists and commuters, the mayor of New Orleans quickly declared a state of emergency.
Speed and flawless execution were of paramount importance, as the city set the repair schedule at 90 days and offered incentives if the construction team finished early. Hard Rock Construction, the project’s general contractor, and the Lafarge team set a more ambitious completion date to get this great city moving again.
The project scope involved building a new structural concrete support wall from within the sinkhole, backfilling the space and resurfacing the damaged sections of Canal Street. In constructing the wall, workers poured a 4-foot-high concrete footing and then built masonry walls on top, filling every CMU block with concrete. Using the masonry walls as permanent forms, the workers finished the job by installing a 26-inch-thick cast-in-place reinforced concrete wall to seal the tunnel.
To accelerate the construction repairs, Lafarge's ready-mix concrete operation in New Orleans supplied 500 cubic yards of a customdesigned Chronolia® concrete mix, a concrete solution by LafargeHolcim. Chronolia® allowed for easier placement and delivered—in only 24 hours—the same strength that conventional concrete gains in 28 days.
The repairs were completed in only 39 days—sooner than expected, by months—at a cost of approximately $2.9 million, which was significantly less than the initial budget of $5 million.
“Chronolia® made a tremendous contribution to speeding up the repairs, getting businesses back in operation and returning tourism in New Orleans back to normal,” said Chris McLellan, project manager at Hard Rock Construction. “For the city and business community, the economic benefits of getting Canal Street up and going again as quickly as possible were significant.”