Aviation | Transportation

Broad River and Chechessee River Bridges

Beaufort, South Carolina

Structural Investigation of the cause of transverse deck cracking and evaluation of crack repairs and the long-term effects of the repairs on bridge deck as part of the SC 170 project for durability and long term maintenance. Each bridge consists of precast bulb-tree girders with cast-in-place deck on cast-in-place piers.  RRJ performed resurveys of the deck cracking 6 and 12 years after construction of the initial crack repairs.

Federal Aviation Administration | Air Traffic Control Towers

Ann Arbor and Flint, Michigan; Fargo, North Dakota; LaCrosse, Wisconsin

Building enclosure condition assessments of four air traffic control towers to identify abnormalities and deficiencies in the exterior building wall envelope contributing to water intrusion and to determine the general condition and serviceability of the exterior wall materials. Based on the condition assessment, RRJ prepared recommendations for future maintenance and/or repairs options for consideration by the FAA.

I35 Bridge Collapse

Minneapolis, Minnesota

The I35W freeway bridge that spans over the Mississippi River suddenly collapsed, killing 13 motorists during the evening rush hour. At the time of the collapse, four lanes of the eight-lane 1,900-foot-long bridge were closed to traffic with staged construction materials and equipmment in preparation to began paving the overlay concrete on the deck top surface that was removed.  Investigation by The National Transportation Safety Board (NTSB) began immediately and RRJ was retained by the deck resurfacing contractor's legal counsel to investigate the cause including whether the contractor's resurfacing operations played any role in the collapse. RRJ gathered physical evidence at the bridge site and off site including information shared by NTSB. RRJ conducted structural analysis computational modeling of the bridge structure to evaluate the original design, the design as subsequently modified, the as-constructed structure including the deformations reported in several steel gusset plates, and comparison of required highway design live loading to the traffic and construction loads present on the bridge at the time of collapse. RRJ and NTSB both determined the probable cause of the collapse to be a gross inadequacy in the original bridge design which had escaped discovery for over 40 years.