PERFORMANCE OF FRP CONNECTORS FOR SEISMIC REHAB OF MICHIE STADIUM

摘要

A seismic evaluation of the West-end bleachers of the United States Military Academy football stadium at West Point, NY, USA, indicated deficiencies that required a retrofit to correct. The selected retrofit design called for fibre reinforced composite (FRP) connectors to connect the columns to the beams and beams to the seating slab and risers. After five years of use, a study was conducted to evaluate the condition of the connectors using an acoustic guided wave (AGW) non-destructive inspection technology. An AGW inspection device was developed to indicate the relative condition of the FRP composite structural upgrade. Since this technology is "non-destructive," it does not require any manual intrusion into the composite material or physical sampling of the composite patch, as did the piezoelectric sensor. This technology was applied to a representative sample consisting of 268 FRP structural upgrade connectors installed at Michie Stadium. The bleachers were divided in 39 sections distributed in three tiers, lower, middle and upper, inside the stadium. The results indicate that a total 5 structural upgrades, located in 2 sections, one on the lower and one of the upper tier, need follow up for potential repair or replacement. The rest of the upgrades were well above the established 40% of AU amplitude threshold.