State-of-Practice and Design Examples for the Use of Noncontact Hooked Bar Lap Splices in Accelerated Bridge Construction

Abstract

Hooked bar lap splices are used in accelerated bridge construction (ABC) operations even though this detail is not addressed in the AASHTO LRFD bridge design specifications. To address this knowledge gap, this paper synthesized the current state of practice of such splices in the US to provide practitioners knowledge of how to use, design, and construct hooked bar lap splices. To accomplish this objective, a survey was distributed to all state Departments of Transportation (DOTs) of the US. Thirty-one responses were received. After discovering that more than half of the survey respondents had some degree of experience using hooked bar lap splices, it was decided to conduct follow-up interviews with representatives from three state Departments of Transportation that had compelling experience with this detail. These efforts revealed that the predominant application of hooked bar lap splices was in the connections of precast deck elements. However, these splices also were reported to have been used within continuity diaphragms, to connect large precast elements (e.g., bent caps), and in cast-in-place construction to reduce required splice lengths. Most DOTs preferred the use of such splices in a noncontact configuration to avoid interference during alignment of precast elements. Furthermore, in the absence of dedicated design guidance and relevant test data, hooked bar lap splices typically have been designed using code provisions for lap splices of straight bars and the tension development length of hooked bars. Despite issues with constructability such as reinforcement congestion within closure joints and interference of hooked bars during splice alignment, practitioners believe that hooked bar lap splices offer a number of advantages in ABC operations. Design examples regarding the use of hooked bar lap splices to connect precast concrete decks and bent caps were developed to complement the survey results.