Structural performance of precast/prestressed bridge double-tee girders made of high-strength concrete, welded wire reinforcement, and 18-mm-diameter strands

This paper presents the development of high-strength precast prestressed double-Tee girders for bridge construction. These girders use high-strength concrete (103 MPa), Grade 550 welded wire reinforcement, and 18-mm-diameter Grade 1860 prestressing strands at 51- by 51-mm spacing. The double-Tee section was used to simplify girder production and erection and to maximize span-to-depth ratio, which improves the construction economy and speed. To evaluate the efficiency of the developed girders, two full-scale 15.24-m long, 1.21-m wide, and 0.5-m deep single-Tee girders were fabricated by a precast producer and tested at the University of Nebraska structural laboratory. Transfer length measurements, development length testing, flexure capacity testing, and vertical and horizontal shear testing were conducted for each specimen. Test results have shown that the proposed high-strength bridge double-Tee girder can be designed using current LRFD bridge design specifications. Preliminary design charts for different girder sizes were presented to demonstrate the efficiency of these girders for short- and medium-span bridges.