Failure Investigation & Litigation Support: Projects

Lowe’s Motor Speedway Bridge Collapse

Charlotte, North Carolina

On May 20, 2000, after the finish of a NASCAR event at the Lowe’s Motor Speedway, one span of a four-span, simply-supported, pretensioned concrete pedestrian bridge that was approximately five years old collapsed injuring 114 people, several with life-threatening injuries. Although this was a private structure used to facilitate crowd movement from the speedway to parking lots, it spanned a major US highway.

The litigation that resulted from this collapse was settled over the following years. WDP was retained by one of the principal parties in the lawsuits and given the task to determine the probable cause of the collapse. The investigation included an extensive review of information from public and private sources; field investigation of the debris from the double-tee beams that collapsed and of those that were dismantled from the other three spans that did not collapse; and an extensive laboratory investigation.

Although the initial investigation concluded that the cause of the collapse was corrosion of the prestressing strands, the reason for the accelerated corrosion of the strands remained an important issue. Through an extensive testing program conducted at WDP’ s laboratory, the precipitator of the corrosion was found to be an accelerating admixture added to a grout material used to fill the cavity left by hold down hardware during fabrication. The admixture was not approved for use in prestressed concrete and was found to be used at a dosage level significantly greater than recommended.

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University Balcony Collapse

Charlottesville, Virginia

On Sunday, May 18, 1997, just prior to the commencement of the 168th final exercises at the University of Virginia, approximately one-third of the Pavilion I balcony collapsed. On May 19, 1997, the University of Virginia Office of Facilities Management requested that WDP conduct an independent engineering investigation to determine the cause of the collapse. The design was traced back to Thomas Jefferson and was constructed in the 1820’s. WDP issued an expert report summarizing the investigation in August 1997.

As part of the investigation, WDP visited the site to make visual observations of the debris, take measurements, gather material samples, and determine the existing conditions of the structure. Laboratory investigations and testing were conducted on two of four hanger rods and on portions of the face beam. Eyewitness accounts of the collapse and conditions prior to the collapse were studied. Analytical studies of the structural system and individual structural elements were conducted.

The most probable cause of the partial collapse was the tensile failure of one of four primary hanger rods used to support the cantilevered edge of the balcony. Laboratory testing revealed that the hanger rods were of late 18th century to mid-19th century vintage and were most likely the original rods used to construct the balcony during the 1820’s. The failed hanger rod had experienced a 96% reduction in effective area due to the long-term corrosion of the rod concealed within the balcony face beam.

WDP redesigned the balconies to meet modern building codes while remaining faithful to the original Jeffersonian architectural design.

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McCaskey East High School

Lancaster, Pennsylvania

WDP was retained by the School District to investigate cracking and spalling observed in masonry bearing walls within McCaskey East High School. The 300,000 sq. ft. school was opened in 1996 and is a four story masonry and precast concrete structure. WDP performed a detailed field investigation including destructive and nondestructive testing to verify construction details of reinforced concrete masonry bearing walls and reinforced masonry columns. The evaluation also included structural analysis of the facility to assess the adequacy of the original design and the effect of construction defects.

The field investigation and analysis results revealed significant structural defects which resulted in closing of the school in July 2001. WDP was tasked with production of a repair design, solicitation of repair bids, and management of the repair project to assure completion of the repair program so that the school could reopen for the 2002 school year.

WDP designed a repair program consisting of four prime contracts. Work was started in January 2002 and was substantially completed in August 2002 permitting opening of the school on time for the 2002 school year. The total repair program cost was approximately $7 million.

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