Because of the optimization of I-girder shapes for maximum flexural efficiency and increasing use of high-strength concrete, shear strength control of member design is becoming more common. The American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications require that the nominal shear resistance of section considered not exceed 8 times the square root of the compressive strength of concrete at service (f' sub c) times the product of width of the web (b sub w) and distance from extreme compressive fiber to centroid of prestressing force (d). If not, the section web must be widened or the depth increased. On the other hand, AASHTO Load and Resistance Factor Design (LRFD) Specifications require a maximum shear limit of 0.25(f' sub c)(b sub w) time the effective shear depth (d sub v). The difference between the two limits may be as high as 100%. The purpose of this research is to theoretically and experimentally establish a limit on shear capacity before member size must be increased. Full-scale experiments have shown that the limit on shear capacity specified in the LRFD Specifications can be reached. A key factor is anchorage of the longitudinal flexural reinforcement at the member end.


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  • Accession Number: 00789061
  • Record Type: Publication
  • Contract Numbers: CMS-9640570
  • Files: TRIS
  • Created Date: Mar 29 2000 12:00AM