Title: Development of load-resistance-factor-design-based prestressed concrete tub girders in Colorado
Date Published: March - April 2024
Volume: 69
Issue: 2
Page Numbers: 66 - 88
Authors: Yail J. Kim and Jun Wang

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This paper presents a new tub girder series for Colorado, conforming to the articles of the American Association of State Highway and Transportation Officials’ AASHTO LRFD Bridge Design Specifications. Although the B618 tub girders developed by the Colorado Department of Transportation in the 1990s have been successfully used for decades, the need for an upgrade is essential to satisfy the requirements of contemporary bridge design and construction. After examining the performance of tub girders selected from six transportation agencies in the United States, an optimization algorithm was employed to generate efficient prototype sections. Then, detailed investigations were conducted to examine various practical aspects concerning the serviceability and ultimate limit states of AASHTO LRFD specifications. Parametric analysis with five bridge superstructures that accommodate up to four traffic lanes demonstrated the applicability of the prototype girders. A simplified version of the prototype sections was also delineated for regional precasters. Furthermore, a comparative study was carried out to evaluate the geometric stability and production costs of the prototype, simplified, and existing B618 girders.