|Front Page Previous Story Next Story||Garage Accident Investigation Continues
By Rich McManus
Photos By John Crawford, Ernie Branson, Brad Moss
On the Front Page...
The cause of the Nov. 29 accident at Multi-Level Parking Garage 9 that killed one worker remains under investigation by the Occupational Safety and Health Administration, which was sifting through debris for evidence during December. Work will eventually continue on the 6-story pre-cast concrete structure once authorities complete their review.
"The purpose of the investigation is to determine from the physical evidence what exactly happened," said Leonard Taylor, acting director of the Office of Research Facilities. "We know generally what happened one of the precast concrete double-T beams that form the floor of the garage slipped and caused a death. But until OSHA releases the site, we can't complete the cleanup and start rebuilding. We all want to mitigate the chances of this reoccurring."
The accident happened around 9 a.m. when a 30-ton section of pre-cast concrete that had previously been set in place with tack (as opposed to final) welds suddenly collapsed from the fifth floor onto the fourth, pinning 25-year-old construction worker Ronal Alvarado Gochez, a recent immigrant from El Salvador. Alvarado Gochez "more than likely died on impact," said Pete Piringer, spokesman for Montgomery County Fire and Rescue Services. The victim's body was not recovered until nearly 12 hours later as rescue workers gingerly made their way toward his position. Shortly after the body was recovered, several more sections of pre-cast concrete called "double T's" also collapsed, although no one was injured in the second incident.
Accidents involving placement of double T's, which are 64 feet long and 12 feet wide, "usually happen when the floor is being lowered, but that's not what happened here," Piringer said.
Taylor explained that garages such as MLP-9, and the newly opened MLP-10 near Bldg. 31 (which engineers examined for possible structural flaws on Nov. 29 and found none), are constructed of pre-cast concrete pieces that are pre-fabricated at a factory then set in place at the construction site. This is opposed to "cast-in-place" concrete, where builders create forms for each floor, place the concrete, wait for it to cure, then proceed up to the next floor. Pre-cast construction "is kind of like an Erector set," he said. "The structure is vulnerable at some points during construction. There are points where all of the elements that make it stable aren't yet fully fastened."
He said that inspectors checked all welds and connections in the already-built portions of MLP-9 and that "all were found to be okay. Where the incident occurred was where [pre-fab sections] were just being put together."
Taylor said the construction job, by contractor Coakley & Williams Construction, Inc., had been proceeding well up to the day of the accident. "The contractor had been conscientious about everything brought to their attention, and everyone associated with the job was very pleased with the overall progress." He explained, "Even though [MLP-9 construction] looks simple, its location made this a very complicated project. It's adjacent to a lot of buried utilities, it involves access to some loading docks and you've got the Clinical Center next door. It's already a greatly constrained site, and there was lots of safety monitoring going on all the time."
He continued, "There is a great deal of quality assurance throughout the design and construction process, just so we can avoid these kinds of things [job-site accidents]. But construction is an inherently dangerous process."
Taylor emphasized that the area affected by the collapsed floors was a very small portion of the overall project, representing about 4 percent of the total. "The actual structural failure was very limited," he said, adding that the extent of damage was still under review as of mid-December. Of a total of some 350 double T's in the project, about 284 had been set without incident when the accident occurred, he noted. "It was number 284 or 285 that fell. Most of the garage is there and stable."
He used an egg-crate image to illustrate the damage: "If you had an egg crate with 3 rows of 9 eggs each, that would total 27 slots or 'bays.' The problem at MLP-9 is confined to one portion of one bay."
Response to the accident was massive. The NIH Police took the first call, Taylor said, and sent out a request to Montgomery County for "mutual assistance." The NIH Fire Department was on the scene moments after being alerted by NIH Police. "The county called in their experts in collapse we don't have that [kind of expertise]," Taylor noted. "They responded with anything and everything they could muster that might be helpful in this situation."
The county Urban Search and Rescue Unit pulled a tractor-trailer onto the scene to augment an array of police and fire command posts already present. Despite the amassed manpower, including several trained canines, many of the responders had to wait for hours until the structure was deemed safe to enter. "It took about 8 hours of erecting temporary shoring before the Fire Department felt it was safe to begin the body recovery operation," Taylor said.
Portions of the west side of the Clinical Center were temporarily evacuated on the order of CC director Dr. John Gallin, in case of any further structural collapse, and netting was strung in front of windows that might have been vulnerable to the flight of debris.
Long-time NIH construction authorities could not recall another construction-related fatality in campus history, although there have been industrial and traffic-associated accidents on campus in which individuals have died, Taylor reported.
He noted that contractors' safety records and past performance are always evaluated prior to selection for work at NIH, and that "in construction, the contractor is responsible for the means and methods of achieving safety...in the United States, contracts are written so that the owner [the government] does not take on the safety liability of the contractor." Taylor also said that Coakley & Williams will remain the prime contractor on MLP-9 once the rebuilding phase starts. "Based on what we know today, there's no reason for us to change."
MLP-9, with space for almost 1,000 cars, had been scheduled to open in March 2005. Its new estimated time of completion has not been set.
A memorial trust to aid Alvarado Gochez's son has been established. Checks should be made out to "Emerson Mauricio Trust Fund," c/o United Bank, 9872 Liberia Ave., Manassas, VA 20110-9821.
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