A Field Installation Using Prestressed Panel Subdecks

About the report:

This final report is a supplement to an earlier report that covered the installation of the first precast, prestressed panel subdecks installed on a bridge in Virginia. The report discusses the inspection of the decks one year after they were completed and the relative ease of construction using the precast subdeck technique as opposed to permanent steel forms and conventional timber forming. Estimates of the relative costs between the three types of forming and consideration of the speed of construction suggest that the precast subdeck technique can reduce superstructure costs and save time and labor during construction. The original bridge design incorporated epoxy-coated reinforcing steel in the cast-in-place upper portion of the decks. This provision was made to protect the reinforcing steel against the intrusion of chlorides since the deck was expected to crack over some of the joints between the subdeck panels. Hairline cracking was observed on some of the decks above the joints between the subdeck-panels. There was no definite pattern to the cracking in some of the other spans, but this may have been due to lack of traffic loading on all but one lane of the twin bridges at the time of the final inspection. While similar cracking is often found in conventionally constructed decks, the joints between the subdeck panels appear to control the location of cracking that might otherwise occur at random locations. It was recommended that the precast subdeck panels technique be considered as a viable alternative for use in the design and construction of bridge decks.

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