This Rapid Research Grant (RAPID) provides funding to collect structural damage data that was caused by the EF 5 tornado in the city of Moore, Oklahoma on May 20, 2013. The damage path of this tornado overlaps the damage paths of two previous tornadoes of 1999 and 2003. It would be interesting to see how the houses reconstructed after the previous tornadoes perform in this tornado. Even though there are close to 1,000 tornadoes recorded each year, typically less than 10 tornadoes are rated EF 4 and EF 5. When an EF 5 tornado impacts a city there is a unique opportunity to document and learn from the building damage. This tornado damaged two schools, dozens of commercial buildings, and over one thousand residential structures. RAPID funding provides an opportunity to document the structural damage before cleanup efforts remove the debris.
The project team will work with other RAPID grantee teams in the field to improve coverage of the damage area and avoid duplication. The team of faculty members and students will travel to the damage site and document failure modes, materials of construction, location of structures with respect to the center of the path, and debris impacts for each documented structure. Social media (twitter) will be used to obtain photos and comments made by citizens. The mining of the social media will enhance damage documentation at specific locations. The RAPID team will develop contour maps of EF ratings and wind speeds based on observed Degrees of Damage. These maps will be compared with past tornado studies to evaluate the similarities and differences. This comparison will contribute to the understanding of the spatial characteristics of tornado wind forces on structures. Building failure progression will be determined in different wind speed zones. The benefits and challenges of using social media to improve disaster assessment will be determined.
On May 20, 2013 a tornado struck Moore, Oklahoma that was classified as an EF5 level wind storm. The total economic loss from this single event was estimated at $3 billion, and was the third major tornado to hit Moore in the previous 15 years. A team of faculty, research scientists, professional engineers, and civil engineering students were tasked with investigating and documenting the performance of critical facility buildings and residences in Moore. The primary objectives of this study included describing a methodology for an easily-reproducible rapid damage assessment, assessing performance of building components, assessing performance of above and below ground storm shelters, analyzing how social media can positively impact communities in the wake of extreme events, and conducting specialized depth studies. The data and recommendations are presented to support future development and/or modification of design guidelines, standards, and the use of social media to mitigate loss caused by extreme events. It was found that 85% of the damage caused by this storm was classified between EF0 and EF2 level winds, as seen in the uploaded wind speed contour map od Moore. Tornado damage is particularly extensive when medium- to large-sized cities with dense concentrations of buildings are hit by strong tornados. Damaging effects from moderate (EF0 to EF2) winds may be avoided by following hurricane coastal design guides. These robust designs are rarely employed for residential construction in tornado-prone areas. The mortality rates from tornado events have not decreased in years, while building damage and overall economic losses continue to grow. New methods are needed to improve engineering design and construction practices in tornado-prone areas. In addition, revision of structural retrofit practices should be considered for mitigating future losses from tornadoes. The findings from this field study are instrumental in validating recent results on tornado loads from laboratory experiments and numerical analyses. A web based map along with the final report can be found at: http://esridev.caps.ua.edu/MooreTornado/MooreTornado.html . The findings of the assessment team are based on observations over three days spent surveying damaged homes and storm shelters in Moore, OK. Key findings are presented in the following bullet points below. A geolocation data methodology was developed and tested for use by extreme event damage assessment teams to collect, attribute, store, and distribute perishable damage data. A web portal was created where the data from the RAPID inspection trip is stored in a GIS-based format. That web portal is free to the public and is found at http://esridev.caps.ua.edu/MooreTornado/MooreTornado.html . Within the web portal is a button which opens the final report from the RAPID inspection. An analysis of residential storm shelter performance was conducted including above and below ground shelters. The results show that no inspected below ground shelters failed from perforation or penetration although these shelters were sometimes found flooded by rain and water from severed water pipes, and in some cases the exits were blocked by debris. One perforation, through an area of poorly consolidated concrete, was observed on an above ground insulated concrete form waffle-grid residential shelter. Residential structures in lower wind speed areas were examined and found to begin to fail at garage door openings and at connections. The comparison between the damage data from this assessment and total force predictions from a laboratory tornado simulator showed promise for lab simulations. Social media websites were mined for images of damage beginning immediately after the storm and continuing after the inspection team left the area. These images added to the level of detail of the overall damage assessment and the research has proven that social media websites can be a viable means of collecting perishable data following extreme events. Remotely sensed aerial imagery gave an understanding of flow and spreading of debris. Using aerial imagery from Moore, it was observed that debris flow is typically manifested in thin "streak lines" spreading out in the direction of travel of the storm.
