Shrinkage Restraint and Loading History Effects on Deflections of Flexural Members

This paper examines the effects of shrinkage restraint cracking and loading history on deflection of reinforced concrete flexural members. Findings show that deflections of lightly reinforced members are highly sensitive to both shrinkage restraint cracking and loading history, while deflections of more heavily reinforced members are insensitive to these effects at full service load. Results of a deflection example are presented along with recommendations for changes to ACI 318. One recommended change is the adoption of a lower cracking moment than the one currently specified in the code to account for shrinkage restraint stresses. It is also recommended that the code evaluate deflection using an effective moment of inertia based on the full dead plus live service load to account for preloading from construction loads prior to installation of nonstructural elements. An evaluation of these changes show that the recommendations will have a significant influence on deflection of lightly reinforced concrete members.

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  • Authors:
    • Scanlon, Andrew
    • Bischoff, Peter H
  • Publication Date: 2008-7


  • English

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  • Accession Number: 01109918
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 28 2008 5:54PM