Effect of Bridge Deck Placement Sequences on Cracking Performance

About the report

Uncertainty persists regarding the influence of continuous deck placement on cracking performance. This study evaluates the effect of bridge deck placement sequence—that is, continuous versus sequential (checkerboard)—through a literature review, a survey of state departments of transportation and Virginia Department of Transportation (VDOT) districts, and an analysis of VDOT bridge condition data. Findings consistently support that shrinkage‑related mechanisms (drying, autogenous, and thermal) are the primary contributors to deck cracking, with placement sequence considered a secondary factor. Furthermore, the study underscores that achieving low cracking performance depends primarily on controlling concrete paste content (preferably below 26.5% by volume) and ensuring high-quality construction practices, particularly proper consolidation, finishing, and curing.

Although continuous placement is often perceived to cause more cracking, most survey respondents reported no significant differences in long‑term deck performance for continuous placement relative to sequential placement. However, some reported taking measures to reduce the risk of cracking, such as limiting the volume or length of continuous placements, using low-shrinkage concrete, or using retarding admixtures to maintain the concrete plastic for extended times. Analysis of Condition State 2 cracking data from 76 VDOT multi‑span continuous steel beam bridges, including 8 placed continuously, showed no statistically significant difference in cracking between placement methods. All the decks were constructed since 2017, reflecting modern materials and construction practices.

Overall, the results suggest that when appropriate materials and construction practices are employed, continuous deck placement may be suitable for multi‑span continuous bridges with concrete volumes less than 360 yd³, provided that the concrete can be maintained in a plastic state during the entire placement (or at least one full span behind the active placement) and the contractor has demonstrated successful experience with continuous deck placement.

Supplemental materials can be found at https://library.vdot.virginia.gov/vtrc/supplements.

_{Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.}

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