Arctic Structure Forensic Study

Performing repairs in the Arctic presents obvious logistical and environmental challenges. Geotechnical concerns must also be considered given the nature of permafrost and the effects of varying subsurface conditions. Many structures on the oil fields of the North Slope of Alaska consist of large modules housing various types of industrial equipment. The equipment often generates significant amounts of heat resulting in large temperature differentials between module interiors and outside arctic air. This temperature differential along with several other factors result in unique deterioration mechanisms throughout the buildings. Given the age and harsh environment of these structures, it is not surprising many are in need of structural repair. This paper is targeted at structural design and inspection professionals and will focus on the forensic study of a specific module located on the North Slope with a deteriorated roofing system. Before implementing repairs, identifying the root cause of the damage is of critical importance. A field investigation was initially performed to assess the structure’s condition. During the investigation, multiple buckled diagonal braces were noted throughout the lateral bracing system, potentially leaving the structure vulnerable to wind and seismic events. Forensic efforts to identify root causes of bracing failures and evaluations performed to assess the criticality of damage as it related to the roof repairs will be discussed. Ultimately, through the forensic study, the root cause of the damage was identified and an appropriate repair strategy is currently in process to mitigate potential instabilities resulting from the failed lateral bracing members.