NCHRP 18-18 [Final]
Design and Construction of Deck Bulb Tee Girder Bridges with UHPC Connections
| Project Data
||Ohio University |
||Dr. Eric Steinberg |
||Published as NCHRP Research Report 999|
Many state DOTs and the Federal Highway Administration (FHWA) are actively promoting accelerated bridge construction (ABC) to reduce traffic impacts, onsite construction time, environmental impacts, and life-cycle costs. However, the usage of prefabricated deck bulb tee (DBT) girders has been limited to relatively short-span and low traffic bridges because of (1) difficulties in accommodating super-elevation transitions on bridge decks, pier skews, differential camber, and stability; and (2) concerns of long-term performance of connections between DBT girders. For example, skewed DBT girders cause bridge deck profile problems because the cambers in adjacent girders do not "line up," and if diaphragms are used to bring the DBT girders into line, large forces are induced.
For the longitudinal and transvers connections between DBT girders, there are a wide range of potential variables to be considered during design and construction of the connections including connection width, bar size, bar spacing, bar detailing (straight, bent or headed), black or epoxy bars, flange thickness, and closure pour materials. The typical DBT girders connected by longitudinal joints with welded tie and grouted connection are not performing well and are not suitable for long-span DBT girder bridges as the load transfer demand on the connection is high. Addressing these topics and use of ultra-high performance concrete (UHPC) as closure pour materials could result in a dramatic improvement in reliability and economy of DBT girders for ABC.
The objective of this research was to propose draft AASHTO LRFD Bridge Design Specifications and AASHTO LRFD Bridge Construction Specifications for design and construction of DBT girder bridges using UHPC for connection.
STATUS: Final, NCHRP Research Report 999