Flexural Behavior of CFRP Prestressed Decked Bulb T-Beam Bridge System

• Published in: Journal of composites for construction
• Main Authors: Grace, Nabil, Ushijima, Kenichi, Baah, Prince, Bebawy, Mena
• Format: Journal Article
• Language: English
• Published: 12.11.2012
• Subjects: Bridges (structures); Bulbs; Diaphragms; Failure; Flanges; Mathematical models; Shear; T beams
• ISSN: 1090-0268
• DOI: 10.1061/(ASCE)CC.1943-5614.0000345

An experimental/numerical investigation was conducted to evaluate the performance of a newly developed bridge system. Through the investigation, a decked bulb T-beam bridge model was constructed, instrumented, and tested under service and ultimate loads. The bridge model had a width of 2.59 m (8.5 ft), an effective span of 9.45 m (31 ft), a depth of 356 mm (14 in.), and was composed of five adjacent decked bulb T-beams. The T-beams were interconnected at their top flanges using 76-mm (3-in.) wide ultra-high performance concrete (UHPC) shear key joints and five full-depth equally-spaced transverse diaphragms along the span. Each diaphragm was post-tensioned with two un-bonded transverse carbon fiber composite cable (CFCC) strands. The investigation revealed that the developed decked bulb T-beam bridge system maintained its structural integrity under service loads with no signs of distress in the shear key joints or the top flanges. UHPC shear keys with the transverse diaphragms were adequate to achieve the monolithic action across the width of the bridge model. In addition, transverse post-tensioning (TPT) forces were effective in restoring the structural integrity of the bridge model when cracks were artificially induced in the shear key joints. At ultimate limit state, the bridge model exhibited compression failure by crushing of the concrete in the top flange. The compression failure was associated with low ductility, dense cracking pattern, and excessive deflection.