An Award-Winning Project
An extremely hot fire occurred inside a metal coating facility that caused serious structural damage to the concrete roof. The building was constructed in the 1950’s and had a conventionally reinforced, concrete-folded roof plate slab designed at 3 & ½ in. thick. The roof span measured 85 ft. between supports. Significant testing, both destructive and non-destructive, was utilized to determine the extent of fire damage. Both structural analysis and modeling of the roof plate stresses were conducted. The stress distribution models and the facility’s unique design eliminated several possible repair options. It was determined that partial depth hydro demolition was required for the highest possible degree of concrete bond strength to the existing structure. Epoxy-bonded composite materials were installed to restore the roof’s flexural strength. Both trial repairs and subsequent trial testing proved this method’s effectiveness. Code analysis of the structure determined that the 1950’s standards for shear were less stringent than the current code. This was evident, as numerous shear cracks were found on the roof plate slab. The epoxy injection was completed in order to bond the shear cracks. Epoxy-bonded composites were installed to provide additional shear strength to the roof plate slab. This project required intricate shoring, construction phasing, 7,140 sq. ft. of hydro demolition concrete repair, 60,000 sq. ft. of epoxy-bonded composite, and 3,150 lineal feet of crack injection.