In 1966, the Canal Street Tunnel in New Orleans was constructed to accommodate an expressway that was never built. It runs for 700 feet (213 meters) between two major thoroughfares: Canal Street and Poydras Street.
Fifty years later, the timber endwall dam at the Canal Street portal collapsed, causing a major sinkhole to form. Water, sewer, drainage, and electrical infrastructure were damaged, and Canal Street was closed to traffic during a busy tourist season.
In response to an emergency request from the city, Mott MacDonald quickly assembled a team of project managers, structural engineers, geotechnical engineers, and civil engineers from around the country.
Mott MacDonald provided the structural design for a reinforced concrete mudsill that would protect the site from inclement weather, and assessed a variety of structural solutions for the collapse. A decision was made to install a poured-in-place reinforced concrete endwall to replace the failed timber endwall.
The chosen solution offered the least impact to existing infrastructure, the lowest cost, and the fastest completion schedule. The project was completed under budget and in record time, and Canal Street was reopened to traffic.