Evaluation of Precast Roof Channel Slabs

Building 103 at the Michoud Assembly Facility in New Orleans, Louisiana, is used to house critical fabrication and assembly operations for the Space Shuttle External Tank. Its roof is approximately 1.66 million sq ft in area and contains approximately 128,000 precast concrete roof panels. After experiencing some incidents of concrete pieces falling from the roof and observing distress in some of the roof panels, Lockheed Martin Manned Space Systems commissioned CTLGroup to evaluate the precast concrete roof panels.

The roof consisted of precast concrete panels spanned between purlins, which in turn were supported by long-span steel trusses. The study was designed to assess the present condition of the panels by investigating a statistically representative population of roof panels. The firm was asked to propose corrective actions and preventive measures to ensure the panels' structural integrity and avoid any possible injury or damage to personnel, equipment, and flight hardware due to roof panel distress.

CTLGroup inspected approximately 25 percent of the in-place roof panels to assess representative conditions throughout the building. Field and laboratory tests were performed on samples removed from the panels to evaluate the concrete's condition and quality, and determine the causes of noted distress. The firm also estimated the costs to address deficiencies.