Re-Evaluation of the Ultimate Shear Behavior of High-Strength Concrete Prestressed I-Beams


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Title: Re-Evaluation of the Ultimate Shear Behavior of High-Strength Concrete Prestressed I-Beams

Author(s): M. K. Kaufman and J. A. Ramirez

Publication: Structural Journal

Volume: 85

Issue: 3

Appears on pages(s): 295-303

Keywords: beams (supports); compressive strength; deflection; detailing; ductility; high-strength concretes; I-beams; prestressed concrete; prestressing steels; shear strength; span-depth ratio; stress transfer; trusses; web reinforcement; Structural Research

Date: 5/1/1988

The ultimate behavior of high-strength concrete prestressed I-beams is studied with trusses as fundamental behavioral models. Six high-strength concrete prestressed American Association of State Highway and Transportation Officials (AASHTO) I-beams were tested. Three modes of failure were observed--flexural, web crushing, and shear tension. Additional comparisons to study the effect of high-strength concrete are conducted with truss models using tests reported in the literature. Higher strength concrete can increase the utilization of web reinforcement by providing sufficient capacity to the compression struts, which flatten and cross more stirrups. The shear tension failures present a potentially serious detailing problem. Adequate ductility of high-strength concrete members can be obtained with proper design of reinforcement. Current ACI and AASHTO procedures are conservative in properly detailed members. Detailing aspects of these members are also illustrated with the aid of truss models.