Investigators from the National Institute of Standards and Technology (NIST) say they have found no evidence of underground voids on the site of the Champlain Towers South collapse, according to a new NIST report.
The team of investigators have studied the site’s subsurface conditions to determine if sinkholes or excessive settling of the pile foundations might have caused the collapse. They have found no such evidence to support that potential cause.
Preliminary evaluation of data indicates about one quarter of an inch or less of settling in the pile foundations supporting the pool deck structure and basement. This would have had minimal impact on the pool deck structure, NIST says.
“Understanding exactly what caused this collapse is taking meticulous investigation and the collection of copious amounts of evidence and information,” said Joannie Chin, director of NIST’s Engineering Laboratory. “Our team members are dedicated to unraveling the complexities of this tragic event, and their rigorous research and analysis will not only help us understand the likely technical cause of the collapse but will improve the safety of our communities.”
The team’s preliminary evaluation of physical and historical evidence found that the pool deck construction deviated from design requirements. Specifically, the number of slab reinforcing bars centered over vertical columns was inadequate, and the reinforcing bars in the top of the slab in the vicinity of the columns were spaced farther apart than the design required, according to investigators. These deviations weakened the slab-column connections, they said.
NIST expects technical work on the investigation to be substantially completed in late June 2024 and aims to release a report with findings and recommendations in late June 2025.
Related Stories
| May 19, 2011
BD+C’s "40 Under 40" winners for 2011
The 40 individuals profiled here are some of the brightest stars in the AEC universe—and they’re under the age of 40. These young architects, engineers, contractors, designers, and developers stood out among a group of 164 outstanding entrants in our sixth annual “40 Under 40” competition.
| May 18, 2011
8 Tips for Designing Wood Trusses
Successful metal-plate-connected wood truss projects require careful attention to detail from Building Team members.
| May 18, 2011
Major Trends in University Residence Halls
They’re not ‘dorms’ anymore. Today’s collegiate housing facilities are lively, state-of-the-art, and green—and a growing sector for Building Teams to explore.
| May 18, 2011
Former Bronx railyard redeveloped as shared education campus
Four schools find strength in numbers at the new 2,310-student Mott Haven Campus in New York City. The schools—three high schools and a K-4 elementary school—coexist on the 6.5-acre South Bronx campus, which was once a railyard.
| May 18, 2011
Addition provides new school for pre-K and special-needs kids outside Chicago
Perkins+Will, Chicago, designed the Early Learning Center, a $9 million, 37,000-sf addition to Barrington Middle School in Barrington, Ill., to create an easily accessible and safe learning environment for pre-kindergarten and special-needs students.
| May 18, 2011
Raphael Viñoly’s serpentine-shaped building snakes up San Francisco hillside
The hillside location for the Ray and Dagmar Dolby Regeneration Medicine building at the University of California, San Francisco, presented a challenge to the Building Team of Raphael Viñoly, SmithGroup, DPR Construction, and Forell/Elsesser Engineers. The 660-foot-long serpentine-shaped building sits on a structural framework 40 to 70 feet off the ground to accommodate the hillside’s steep 60-degree slope.
| May 18, 2011
New center provides home to medical specialties
Construction has begun on the 150,000-sf Medical Arts Pavilion at the University Medical Center in Princeton, N.J.
| May 18, 2011
Improvements add to Detroit convention center’s appeal
Interior and exterior renovations and updates will make the Detroit Cobo Center more appealing to conventioneers. A new 40,000-sf ballroom will take advantage of the center’s riverfront location, with views of the river and downtown.
| May 18, 2011
One of Delaware’s largest high schools seeks LEED for Schools designation
The $82 million, 280,000-sf Dover (Del.) High School will have capacity for 1,800 students and feature a 900-seat theater, a 2,500-seat gymnasium, and a 5,000-seat football stadium.