A six-span prestressed concrete bulb tee beam bridge, designed to eliminate the need for a conventional cast-in-place concrete deck, was constructed in minnesota in 1986. two end spans of this 484.7-ft (147.8-m) long structure were 70 ft (21.3 m) clear, and four interior spans were 85 ft (25.9 m) clear. Bars 1 in. (2.54 cm) in diameter were used to transversely posttension 6-ft (1.8-m) wide top fanges of five 40-in. (100-cm) deep bulb tee beams. A slip-formed, cast-in-place, reinfored concrete railing limited required formwork to only the low-slump wearing course, expansion devices, and pier diaphragms. A 2-in. (5.1-cm) minimum concrete overlay provided a good riding surface. Construction of this structure was completed in just 5 months at a cost of $450/sq yd ($538/sq m), with a savings of about 25percent over a conventional design. this paper appears in transportation research record no. 1180, bridge design and testing.
Samenvatting