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原文传递 Development of Resistance Factors for LRFD Design for FRP Strengthening of Reinforced Concrete Bridges.

题名：	Development of Resistance Factors for LRFD Design for FRP Strengthening of Reinforced Concrete Bridges.
作者：	atadero, r. a. karbhari, v. m.
关键词：	fiber reinforced composites, prestressed concrete structutres, strength, structural engineering, calibration, durability, loads(forces), reliability, degradation, methodology, simulation, evaluation, trends, california
摘要：	Externally-bonded fiber reinforced polymer (FRP) composites are an increasingly adopted technology for the renewal of existing concrete structures. In order to encourage the further use of these materials, a design code is needed that considers the inherent material variability of the composite, as well as the variations introduced during field manufacture and environmental exposure while in service. Load and Resistance Factor Design (LRFD) is a reliability-based design methodology that provides an ideal framework for these considerations and is compatible with existing trends in civil engineering design codes. This investigation studies the application of LRFD to FRP strengthening schemes, with an emphasis on wet layup, carbon-fiber composites applied to reinforced concrete T-beam bridge girders. Models to describe variation in the existing structural materials and the structural loading are drawn from the literature. Techniques for reliability analysis are discussed and existing work on externally bonded FRP reliability is surveyed. Stochastic variation in the FRP is characterized based on tensile testing of several sets of field manufactured wet layup composites. A General design procedure applicable to many different situations is proposed using a composite specific resistance factor to consider material variability, a set of Application Factors to account for deviations introduced through field manufacture and an environment and service-life specific factor for FRP degradation. Preliminary resistance factors for design of FRP strengthening are calibrated over a range of design scenarios. FRP degradation is considered based on existing durability models, and continued degradation of the structure due to general corrosion of the reinforcing steel is included. The girders used for calibration are selected as representative examples from a sample of California bridge plans. The reliability has been evaluated using simulation and first-order methods. An example of the proposed design procedure, using the calibrated resistance factors, is provided. / NOTE: Final rept. / Supplementary Notes: Sponsored by California State Dept. of Transportation, Sacramento. Engineering Service Center. and Federal Highway Administration, Sacramento, CA. California Div. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
总页数：	u0816；410p
报告类型：	科技报告