Emergency Shoring At The Paul E. Garber Preservation, Restoration, and Storage Facility
On February 10, straining under the weight of a record snowfall, the roof of a storage facility in Suitland, Md., collapsed. The Paul E. Garber Preservation, Restoration, and Storage Facility belongs to the Smithsonian Institution’s National Air and Space Museum and serves as the primary repository for the museum’s irreplaceable artifacts, , and works of art. The Smithsonian turned to Clark Construction Group, LLC, to stabilize the structure and prevent further damage. After working with a structural engineer to survey the site, Clark used its full breadth of capabilities to shore up the falling facility so the Smithsonian could safely recover its artifacts.
Clark Interiors, which has been working at the Smithsonian’s Museum Support Center on the POD-3 Renovation project since 2008, initially received the call for assistance from museum officials. The company brought in renowned structural emergency specialist Allyn Kilsheimer of KCE Structural Engineers PC to evaluate the Garber building’s damage and design an emergency shoring system to prevent further collapse.
The building’s roof had completely caved in and rested on top of high load shelving units and the crates stored on them. This put hundreds of artifacts at risk, including a prototype of the Mars Exploration Rover. To complicate matters, as snow melted and eased the burden on the structure’s roof, the warehouse continued to move as much as two inches.
One of the most damaged sections of the building also contained some of the most fragile items. During the collapse, a roof member pierced a specially-controlled environmental chamber for the museum’s 1,200-piece art collection, exposing it to the raw atmospheric conditions and moisture.
The stabilization effort began on March 16. Clark Foundations first welded rakers to columns along the warehouse’s perimeter. For maximum support, the rakers were bolted to adjacent concrete on the ground and anchored by large concrete weights. Clark Concrete then installed 38 high-strength shoring towers that arrived on-site from Georgia less than 48 hours after Clark’s first damage assessment.
Throughout the shoring process, safety was a primary concern. Clark’s Safety Department developed a site-specific emergency plan shortly after the structural shoring system was devised and all workers reviewed the plan before the start of work each day. Special equipment, including the Jaws of Life and airbags capable of lifting 20 tons, were brought on-site as a precaution. A crane was erected and placed on stand-by in the event of emergency lifting.
In addition to these precautions, a crew of field engineers constantly evaluated the building’s structure for movement. A wind monitor was set up to alert workers to any sudden gusts or dangerous changes in weather conditions. Both Clark Concrete and Clark Foundations brought extra workers to the site as observers. Crews performed work in teams of two or three. Each work crew was watched by a similarly-sized group observing for safety purposes. Each observation crew was equipped with an air horn to notify workers inside the structure of any imminent danger and need for evacuation.
An identification system ensured that each worker was accounted for at all times. All workers were assigned a number and two corresponding tags. Before entering the building, a worker moved one of his or her tags from “Out” to “In” on a public bulletin board and carried the second tag at all times. Clark assigned one person to solely oversee the bulletin board.
Clark completed the stabilization efforts on Friday, March 19. The following week, Smithsonian officials began removing artifacts and collections for relocation. With nearly 100 percent of the items safely recovered, the Smithsonian had the Garber building demolished.