Tranverse Deck Reinforcement for Use in Tide Mill Bridge

Abstract

The objective of the research presented in this thesis was to study and optimize the transverse deck reinforcement for a skewed concrete bridge deck supported by Hybrid Composite Beams (HCB's). An HCB consists of a Glass Fiber Reinforced Polymer outer shell, a concrete arch, and high strength seven wire steel strands running along the bottom to tie the ends of the concrete arch together. The remaining space within the shell is filled with foam. The concrete arch does not need to be cast until the beam is in place, making the HCB very light during shipping. This lowers construction costs and time since more beams can be transported per truck and smaller cranes can be used. HCB's are quite flexible, so AASHTO LRFD's design model for bridge decks, as a one-way slab continuous over rigid supports, might not apply well to the HCB's deck design.

A skewed three HCB girder bridge with a reinforced concrete deck and end diaphragms was built in the laboratory at Virginia Tech. Concentrated loads were applied at locations chosen to maximize the negative and positive moments in the deck in the transverse direction. The tests revealed that the transverse reinforcement was more than adequate under service loads.

An Abaqus model was created to further study the behavior of the bridge and to help create future design recommendations. The model revealed that the HCB bridge was behaving more like a stiffened plate at the middle section of the bridge, indicating that the flexibility of the girders needed to be considered.