Hard Rock Hotel
The Hard Rock Hotel, at the corner of Canal and North Rampart Streets in New Orleans, was already topped out, when a progressive failure started the morning of October 12, 2019, in the 10-story, structural steel framing above the 8-story post-tensioned garage, below. That failure proceeded to the point where the two (2) Liebherr tower cranes serving the construction were free-standing above the 8th Floor slab and moving freely in the wind coming off the Gulf.
Immediate efforts by New Orleans authorities focused on locating three workers who were unaccounted for following the collapse and ensuring the area around the damaged structure/cranes was cleared. All three workers were located, deceased; however, two were trapped in post collapse debris.
Once the condition of the structure and cranes was reviewed by the City of New Orleans (NOLA), they cordoned off a 16-square block area of downtown, including Canal Street and a portion of the French Quarter, effectively shutting down traffic in an even larger area due to one-way street configurations.
Given their emergency contract relationship with the State of Louisiana and City of New Orleans, D.H. Griffin Wrecking Co., Inc. (DHG) was called to the site within 24 hours following the collapse. After looking at the condition of the structure and cranes, David Griffin contacted CDI about mobilizing toward developing an explosives crane lowering solution given the approach of a tropical depression which could bring winds that would topple the cranes in an uncontrolled fashion, causing damage to private property, City infrastructure and the newly renovated Saenger Theater directly across North Rampart Street.
Liebherr was contacted the day of the collapse on an emergency basis regarding traditional lowering or emergency pick-down of their equipment. Review of photographs/video of the cranes and the extent of damage sustained to the towers during the initial failure caused Liebherr to back away from recommending such efforts.
Mark Loizeaux, President of CDI, reviewed structural and crane conditions before conferring with DHG and their structural engineer, Thornton Tomasetti (TT) on the safest path forward. An agreement was put in place between DHG, NOLA, the State of Louisiana and the developer to permit the use of explosives to stabilize site circumstances by lowering the cranes to an extent where adjacent properties would not be threatened and the safety zone could be reduced to a tenable size.
Working with the cooperation of the Louisiana State Police Department, explosives division, CDI mobilized their DOT explosives transport vehicle to Tennessee to pick up the shaped charge explosives needed to sever the crane booms and counterweights hangers while severing the four (4) tubular corners and diagonal struts in the towers to allow CDI to allow CDI to control the direction of fall of crane debris.
The boom of the southernmost or Alpha Crane, closest to Canal Street, was close to the hotel roof. CDI felt it could be dropped into the Hard Rock building, and hook the boom over the southern edge of the hotel structure, preventing the upper portion of the tower and the A-frame above from kicking backwards toward the newly renovated Saenger Theater to the west across North Rampart Street.
“Thanks so much for your team’s hard work and professionalism in lowering the tower cranes in an incredibly difficult environment. Our community is much safer now and we appreciate the fast and good work.” – Ramsey Green, Deputy Chief Administrative Officer – City of New Orleans
The height of the boom of the northernmost or Charlie Crane, closer to Iberville Street, precluded the hooking of the boom over the eastern edge of the hotel, and the natural failure mode of tower cranes dictated that if the counterweight arm released from the tower, the counterweight would likely pull the upper tower and crane boom backwards to the northwest following explosives severance of the boom and counterweight hangers. The latter worst-case scenario is what CDI planned for with the northern structure.
DHG worked on a fast-track basis to place protection for the Saenger Theater and surface protection above gas and electric utilities just beneath the surface of North Rampart and Iberville to protect them against impact and penetration of debris from the fall of the Charlie Crane to the northwest.
NOLA Police and Fire Department agencies, well experienced in crowd control, evacuated the area on the morning of October 20, 2019, and CDI felled both tower cranes, exactly as discussed with Mayor Latoya Cantrell and Fire Chief Tim McConnell, prior to the crane lowering operation.
With the threat of uncontrolled crane collapse removed, NOLA was positioned to work with the Project Developer, 1031 Canal, LLC, to finalize a plan for demolition of the structures and recovery of the two deceased workers.