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原文传递 Fatigue and Shear Behavior of HPC Bulb-Tee Girders, Interim Report. Interim rept. Feb 00-Oct 03.

题名：	Fatigue and Shear Behavior of HPC Bulb-Tee Girders, Interim Report. Interim rept. Feb 00-Oct 03.
作者：	bruce, b. russell, h. roller, j.
关键词：	Bridges-(Structures; Shear-strength; Girders-; Fatigue-.;High-strength-concretes; Concretes-; Concrete-durability; Welded-wire-fabric; Concrete-reinforcement; Prestressed-concrete.
摘要：	Three 96-ft (29.3-m) long, 72-in. (1.83-m) deep, precast, pretensioned bulb-tee girders were tested to evaluate behavior under flexural fatigue and static shear loadings. The three girders had a design concrete compressive strength of 10,000 psi (69.0 MPa) and incorporated 0.6-in. (15.2-mm) diameter, Grade 270, low relaxation prestressing strands. The shear reinforcement quantities at the ends of each girder were selected to evaluate the applicability of the shear strength design provisions of the AASHTO Standard Specifications for Highway Bridges and the AASHTO LRFD Bridge Design Specifications. Shear reinforcement consisted of conventional bars or deformed welded wire reinforcement. The three prestressed concrete girders were produced in a commercial plant. Prior to testing, a 10-ft (3.05-m) wide reinforced concrete deck slab was added to each girder. After completion of fatigue testing, each girder was cut in half and the six girder ends tested to evaluate static shear strength. The bulb-tee girder performed satisfactorily under 5,000,000 cycles of flexural fatigue loading when the tensile stress in the extreme fiber of the bottom flange was limited to a maximum value of 610 psi (4.21 MPa). When the tensile stress was 750 psi (5.17 MPa) or larger, fatigue fractures of the prestressing strand occurred and the fatigue life of the girder was reduced. Measured shear strengths consistently exceeded the strengths calculated according to the AASHTO Standard Specifications for Highway Bridges and the AASHTO LRFD Bridge Design Specifications using both design and measured material properties. The existing limitation of 60,000 psi (414 MPa) for the design yield stress of transverse reinforcement in both AASHTO specifications is conservative. Higher reinforcement yield strengths can be utilized in the design of prestressed concrete beams. Welded wire deformed reinforcement can be used as an equally effective alternate to deformed bars as shear reinforcement.
报告类型：	科技报告