Grappler bucket teeth of Caterpillar 345B backhoe rip out open web joist/bar joist that supports roof, leaving roof to sag into opening. Basic building is concrete block structure that supports bar joist roof structure. Steel tension straps/bars in background provide diagonal X bracing/shear bracing against wind and other forces against the side of building. Washtenaw near Huron Parkway, Ann Arbor, Michigan. January, 2007.