AASHTO FRPS-1:2012 GUIDE SPECIFICATIONS FOR Design of Bonded FRP Systems for Repair and Strengthening of Concrete Bridge Elements. When concrete and atmospheric temperatures exceed 90°F, difficulties may be experienced in application of the epoxy compound owing to acceleration of the reaction and hardening rates. if ambient temperatures above 90°F are anticipated, work should be scheduled when the temperature is lower, such as in the early morning hours. if it is necessary to apply epoxy compounds at temperatures exceeding 90°F, the work should be supervised by a person experienced in applying epoxy at high temperatures. Epoxy systems formulated for elevated temperature are available (ACI 503R-93). At temperatures below 40°F. difficulties may occur due to deceleration of the reaction rates. The presence of frost or ice crystals may also be detrimental to the bond between the FRP and the concrete. Evaluate moisture content or outgassing of the concrete by determining if moisture will collect at bond lines between old concrete and epoxy adhesive before epoxy has cured. This may be accomplished by taping a 4 x 4 ft (1 x rn) polyethylene sheet to the concrete surface. If moisture collects on the underside of the polyethylene sheet before epoxy would cure, then allow concrete to dry sufficiently to prevent the possibility of a moisture barrier between old concrete and new epoxy(ACI 503R-93). During installation, sample cups ot mixed resin should be prepared according to a predetermined sampling plan and retained for testing to determine level of curing in accordance with ASTM D2583. The relative cure of the resin can also be evaluated on the project site by physical observation of resin tackiness and hardness of work surfaces or hardness of retained resin samples. C1.4.1 The resistance criteria in these Guide Specifications were developed using modern principles of structural reliability analysis, which are consistent with those on which AASHTO LRFD is based. Structural reliability analysis takes the uncertainties in concrete, steel, and FRP material strengths and stiffnesses into account using rational statistical models of these key engineering parameters. The criteria for checking safety and serviceability of structural members and components that have been strengthened with externally bonded FRP reinforcement are based on a target reliability index, 1, equal to 3.5 under inventory loading, which was the target value assumed in the development of AASHTO LRFD. The factored resistance and factored loads used in these checks are consistent with those found in customary engineering...
Download Address
Download