Colorado. Dept. of Transportation. Research Branch
Abstract
This report presents the development of tub girders for prestressed concrete bridges complying with the Load and Resistance Factor Design (LRFD) method. In addition, the use of 0.7 in. strands is elaborated for the B618-U girders of the Colorado Department of Transportation. In the first part of the report as regards a state-of-the-art review, technical parameters are categorized in accordance with physical characteristics and corresponding contents are examined. The second part of the report suggests a new tub girder series. After understanding the performance of tub girders selected from six transportation agencies in the nation, an optimization algorithm is employed to generate efficient prototype sections. Afterward, detailed investigations are conducted to appraise various practical aspects. A simplified version of the prototype sections is also delineated for regional precasters. A comparative study is carried out to evaluate the geometric stability and production costs of the prototype, simplified, and existing B618-U girders. Implementation: A new tub girder series is proposed to improve structural efficiency and the potential implementation of 0.7 in. strands is discussed for bridge construction in Colorado
