A
medical facility building located in Houston, Texas incorporating a
basement housing equipment and laboratories
implemented a flood protection system
consisting of multi-layered internal and external flood walls. Part of the
flood protection system included strengthening of a portion of the
existing basement roof to carry the weight of seven feet of water. The basement roof
structure is formed by a
reinforced concrete pan-joist system supported by
girders. A review of the structure showed that the slab and joists had sufficient
capacity to resist the loads due to the floodwaters. However, the girders did
not have adequate flexural capacity and required strengthening. Several repair
options were considered. The final option consisted in the use of Carbon Fiber
Reinforced Polymer (CFRP) to strengthen the existing girders. CFRP was
epoxy-bonded to the soffit of the girders. To simplify the retrofit, the design
allowed for cracking and ensuing moment redistribution at the column supports.
Construction was performed without any disruption to the existing mechanical,
electrical, and plumbing (MEP) lines at the basement ceiling, and was completed
in a timely fashion without any impact to building operations.