First Two-Stage PT Wide-Flange Girder Bridge in California

摘要

The first post-tensioned spliced wide-flange girder bridge, which is Riego Road Overcrossing, has been designed by California Department of Transportation (Caltrans) two years ago. Now it has been constructed and the new bridge is expected to be open at the end of this year. The project is a new interchange at Riego Road and State Highway 99 in southern Sutter County. The bridge has two spans, 154’ and 141’, over Hwy 99. Cost of the project is $31 millions. Caltrans’ new standard PT wide-flange girders have been used for this project. Since this is the first California post-tensioned spliced wide-flange girder bridge designed by Caltrans, it faced many challenges from the different phrases. Feasibility, design ability, constructability and cost are being challenged along the whole project process. During the design, manufacture and construction, Caltrans worked with the Contractor and the precast sub-contractor to have solved various problems. There are several lessons learned from this project. Caltrans has developed two new and improved standard precast wide-flange girder shapes in recent years. One of the new girder types, post-tensioned WF girder type, has the span capability of exceeding 200 ft, which is very comparable to those of cast-in-place post-tensioned box girders. Combined with the use of high-strength concrete, the spans and girder spacing can be maximized. The standard 8-inch web is for post-tensioned girders where splicing for continuity is applied. The new girders serve to promote the Accelerated Bridge Construction (ABC), as well as economic design. This paper illustrates Riego Road Project as a case study to present the design, shop drawing review, manufacture and construction for this new post-tensioned spliced WF girders project. The author wants to share the valuable experience and important information with other State Agencies and PCI members about using precast girders for long span bridges.