Experimental Behavior of Full-Depth Precast Concrete Panels for Bridge Rehabilitation

A significant number of highway bridges in the U.S. are in need of replacement or rehabilitation. The rehabilitation process is dependent upon the urgency and magni-tude of the damage reported, as well as the type and extent of rehabilitation in terms of time and cost of construction. An effec-tive and economic design concept can be implemented for the rehabilitation of existing highway bridges and new bridge construction involving the application of full-depth precast or precast prestressed concrete panels that can be installed on concrete or steel beams. The potential to adopt the proposed system is promising and can be of great interest nationwide. To verify the effectiveness of these struc-tural systems, an experimental study was conducted on the proposed system to inves-tigate the joints between adjacent precast panels, shear pocket connection between the precast panels and its supporting system to achieve full composite action, and the amount of concentric prestressing force that is needed in the deck system in the lon-gitudinal direction to provide continuity and to secure the tightness of the transverse joints. The experimental objectives of the study included modeling a continuous pro-totype bridge with full-depth precast pan-els on steel stringers. These models were subjected to static and fatigue simulated AASHTO truck loading. For the purpose of studying the effect of post-tensioning, the bridge deck system for the first bridge model was not post-tensioned longitudi-nally, while the decks for the second and third bridge models were post-tensioned with a prestress level of 1.43 and 2.62 MPa (208 and 380 psi), respectively. The effect of post-tensioning was clearly evi-dent in that first cracking initiated in the transverse joints near the central support (maximum negative moment region) for the nonpost-tensioned bridge model, while first cracking initiated in the central panel (over the central support) for the last two bridges. The applied load that caused the nonpost-tensioned bridge deck to crack was about 1/3 that of the post-tensioned bridge deck models.