Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Civil Engineering

Major Professor

Zhongguo (John) Ma

Committee Members

Edwin G. Burdette, Richard M. Bennett, Cheng-Xian Lin


Speed of construction has become a critical issue to minimize disruption of traffic and commerce. One of the promising systems for accelerated bridge construction is the use of the decked bulb-tee (DBT) girders for the bridge superstructure. An integral deck that is precast and prestressed with the girder provides benefits of rapid construction along with improved structural performance. However, the limited research and concerns about the use of longitudinal joints as well as intermediate diaphragms limit widespread of the DBT bridge system.

This dissertation presents a study of the continuous for both moment and shear transfer longitudinal joint detail and the optimized use of intermediate diaphragms. Eight concrete beams connected by different reinforcement details were statically tested and the potential continuous joint detail was proposed. Four concrete slabs connected by the proposed joint were statically and cyclically tested. Based on the testing results evaluated on flexural capacity, curvature behavior, cracking, deflection and steel strain, the developed continuous longitudinal joint detail is a viable connection of the DBT bridge system.

The effect of intermediate diaphragms on the performance of the DBT bridge system was investigated by the finite element modeling which was calibrated by field testing data. Five bridge models with different diaphragm details were developed and analyzed. It is recommended that one intermediate diaphragm at midspan be used for the purpose of accelerated construction of the DBT bridge system.

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