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原文传递 Effect of Fatigue on Understrength Shear-Critical Reinforced Concrete Beams Reinforced with External CFRP Stirrups.

题名：	Effect of Fatigue on Understrength Shear-Critical Reinforced Concrete Beams Reinforced with External CFRP Stirrups.
作者：	budek, a. taylor, j. nash, p. taylor, j. nash, p.
关键词：	reinforced concrete, carbon fiber, retrofitting, shear reinforcement, force displacement
摘要：	This is a technical report detailing the testing of six under strength reinforced concrete beams subjected to fatigue loading. Three beams were tested as-built, and three were reinforced with external carbon fiber stirrups. Tests to failure of as-built/retrofitted beam pairs were conducted statically, and after 100,000 and 1,000,000 cycles respectively. The beams subjected to fatigue loading were first loaded quasi-statically to first cracking. The load amplitude for fatigue was set to give a peak load at 75% of that for first cracking. The as-built beams failed through rupture of the internal steel shear reinforcement. The CFRP beams failed through rupture of the concrete under the CFRP-concrete interface. The load distribution mechanism in the fatigue loaded CFRP-reinforced beams was different from the statically loaded example in that the strains in the CFRP were substantially higher through the post-fatigue loading regime. This suggests that the crack surfaces were 'worked', or polished by fatigue loading, degrading the concrete shear-resisting mechanism. The CFRP-reinforced beams also displayed different crack patterns from the unreinforced examples, in that a small number of wide shear cracks formed, inclined at 45 degrees. Cracking in the as-built specimens was more widely spread, and the cracks were narrower. The force-displacement response of CFRP-reinforced beams was found to be bilinear in all cases, as was the response of the as-built beam subjected to 1,000,000 cycles. The as-built beams subjected to no cyclic loading, and 100,000 cycles, had a linear force displacement response. An equation is presented which predicts ultimate shear strength of the CFRP-reinforced beams within an LRFD framework. / Supplementary Notes: Sponsored by Department of Transportation, Washington, DC. Office of Research and Special Programs. / 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：	u0713；24p
报告类型：	科技报告