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原文传递 DESIGN OF SEMILIGHTWEIGHT BRIDGE GIRDERS: DEVELOPMENT-LENGTH CONSIDERATIONS.

题名：	DESIGN OF SEMILIGHTWEIGHT BRIDGE GIRDERS: DEVELOPMENT-LENGTH CONSIDERATIONS.
作者：	Peterman-RJ; Ramirez-JA; Olek-J
关键词：	Beams-; Bonds-; Compressive-strength; Cracking-; Failure-; Flexure-; Girders-; Laboratory-tests; Lightweight-concrete; Moments-Mechanics; Rectangular-beams; Semilightweight-concrete; T-beams; Transverse-reinforcement
摘要：	In a recent study, 25 development-length tests were conducted on rectangular and T-shaped semilightweight beams having design compressive strengths of 48 MPa (7,000 psi) and 69 MPa (10,000 psi). In the rectangular beam tests, the design moment capacity was exceeded in every case. However, in the tests on T-shaped beams, bond failure occurred in some specimens immediately after the formation of a flexure-shear crack. Additional tests were then conducted on similar T-shaped beams having varying amounts of transverse reinforcement near the point load. These tests showed that bond failure could be prevented by increasing the transverse reinforcement near the point of maximum moment. The study showed that the shift in the tension force that occurs when flexural cracks turn diagonally may lead to bond failure if sufficient anchorage of the strand is not provided. Therefore, the investigators recommend that the current AASHTO requirements for strand development be enforced at a "critical section" located at a distance d sub p from the point of maximum moment toward the free end of the strand, where d sub p is the distance from the extreme compression fiber to the centroid of the prestressed reinforcement.
总页数：	Conference Title: Fifth International Bridge Engineering Conference. Location: Tampa, Florida. Sponsored by: Transportation Research Board
报告类型：	科技报告