KBP Coil Coaters Structural Concrete Repair

An Award Winning Project

An extremely hot fire occurred inside a metal coating facility causing serious structural concrete roof structure damage. The building was constructed in the 1950’s using a conventionally reinforced concrete folded roof plate slab, designed at 3-1/2-inches thick. The roof span was 85 feet between supports. Significant testing, both destructive and non-destructive was utilized to determine the extent and boundaries of the fire damage. Structural analysis and modeling of the roof plate stresses were completed. The stress distribution models and unique original design eliminated several conceptualized repair schemes. It was determined that partial depth hydro-demolition was required to ensure the highest concrete bond strength. Epoxy bonded composite materials were installed to strengthen the repaired roof section in flexure. Trial repairs and subsequent trial testing proved the repair scheme effectiveness. Code analysis of the structure determined that the 1950 code for shear was less stringent than the current code. This was evident as numerous shear cracks were found in the roof plate slab. Epoxy injection was completed to bond the shear cracks. Epoxy bonded composites were installed providing additional roof plate slab shear strength. Intricate shoring, construction phasing, 7140 square feet of hydro demolition concrete repair, 60,000 square feet of epoxy bonded composite and 3150 lineal feet of crack injection was completed.

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