Advantages of Prefabricated Deck System Bridge Components

Bridge components can be prefabricated offsite and assembled in place in Prefabricated Deck System. This is the main advantage of this construction method.Other advantages include removing deck placement from the critical path of bridge construction schedules, cost savings, and increased quality due to controlled factory conditions. However, proper design and construction of the joints must be adequately addressed to ensure adequate performance. 

Partial-depth prefabricated deck panels act as stay-in-place forms and not only allow more controlled fabrication than fully cast-in-place decks, but also could increase the strength of the finished bridge deck due to the utilization of prestressed panels. They have been commonly used in many states; however, there is a reported history of performance problems associated with cracking and spalling of the cast-in-place deck.

The full depth prefabricated panels allow reducing the construction time and thus traffic disruption. For example, the Dead Run and Turkey Run Bridges located on George Washington Memorial Parkway, Virginia needed to be kept open to traffic on weekdays during replacement of bridge decks in 1998. The Dead Run Bridge consists of two structures carrying two traffic lanes each; the bridge is 305 feet long with a three-span configuration (Figure 2.37). The Turkey Run Bridge is also two structures that each carry two lanes of traffic having a length of 402 feet in a four-span configuration. Both bridges have an 8-inch thick concrete deck supported on steel beams with non-composite action. The non-composite aspect of the original design, along with the use of prefabricated concrete post - tensioned full-depth deck panels, facilitated quick deck replacement and allowed the structures to be kept open to daily traffic between Monday morning and Friday evening.

The construction sequence closed the bridge on Friday evenings and included: saw-cutting the existing deck into transverse sections that included curb and rail; removing the cut sections of the deck; setting new prefabricated panels; stressing longitudinal tendons after all panels in a span were erected; grouting the area beneath the panel and above the steel beam; opening the bridge to traffic by Monday morning. This construction sequence allowed the complete replacement of one bridge span per weekend.