the back of the building survived. According to a study of the collapse, the tornado hit the south corner of the store and lifted the roof up causing the west walls to collapse into the store. The walls on the east side (where the people survived) collapsed out. Only two walls remained standing. Engineers said that stronger roof-to-wall connections might have tempered the collapse. Two other big box stores at the corner that had concrete block construction (an Academy Sports + Outdoors and Walmart) lost their roofs but the walls remained intact. Those buildings were not directly hit by the tornado but the Home Depot building suffered a direct hit. Three people died in the Walmart, but 200 survived. The engineers told the Star that when concrete blocks fail they usually break apart, and do not come down in huge slabs. Home Depot, which has hundreds of stores built with tilt-up, said it disagreed with the finding and that it would use tilt-up when it rebuilt the Joplin store. Shortly after publication of the Kansas City Star article, the technical committee of the Tilt-Up Concrete Association (TCA) formed a task force to investigate the claims presented in the article. With the cooperation of Home Depot, the task group performed detailed engineering calculations, research and investigation of the claims posed in the article. This task force consisted of a nationwide group of practicing structural engineers with a diverse range of experience in tilt-up construction and "big box" buildings. The final report was published on January 12, 2012. "The information provided in these findings will help Association efforts to promote the benefits of site cast Tilt-Up construction and dispute many of the claims presented in The Kansas City Star article." Findings of the Task Force One of the conclusions of the Task Force's report was "Recommend to ICC and direct to building owners the use of storm shelters in lieu of designing buildings for high winds. The TCA should develop specific Tilt-Up based storm shelter designs for winds of up to 200 MPH that would compete against alternative masonry, precast, or cast-in-place designs. Storm shelter design is addressed in 2009 IBC, section 423 and ICC-500." Gallery See also Lift slab References External links Tilt-Up Concrete Association TCA Awards Tiltup.com Tilt Up Panels Safety Procedures Building engineering Structural system Building Concrete