Flexural Testing of Structural Insulated Panels Before and After Creep Testing

Laya Khademibami, Rubin Shmulsky, Christopher Adam Senalik, Roy Daniel Seale, Robert J. Ross, Mostafa Mohammadabadi, Keith Ward, Thomas Williamson

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The effect of duration of load testing on flexural properties of structural insulated panels was investigated herein. Structural insulated panels were manufactured by a member of the Structural Insulated Panel Association (SIPA) in accordance with International Code Council-Evaluation Service Report 4689. Two panel depths 16.5 cm and 31.1 cm (6.5 in. and 12.25 in.) were tested in short duration 1/3-point bending per American Society for Testing and Materials standards. All structural insulated panels had joints or discontinuities in the foam layer in a location that was subject to shear stress during the bending tests. Failure mode for all panels was horizontal shear within the foam layer. Within each panel depth, no statistically significant differences were detected between the maximum load values before and after creep testing. This finding indicates that the creep test loading was not detrimental to the strength of the structural insulated panels. While the results were not deemed to be statistically different for the Δymax (midspan deflection at Pmax) for the 31.1 cm depth class, they were statistically different from the 16.5 cm depth class. Overall, it appeared that there was minimal effect of the creep test loading on Δymax of the SIPs.

Original languageEnglish (US)
Pages (from-to)3319-3327
Number of pages9
Issue number2
StatePublished - May 1 2023
Externally publishedYes

Bibliographical note

Funding Information:
This publication is a contribution of the Forest and Wildlife Research Center, Mississippi State University. The authors acknowledge the support from USDA Forest Service Forest Products Laboratory (FPL) in Madison, Wisconsin, as a major contributor of technical assistance, advice, and guidance to this research. The authors also acknowledge USDA Forest Products Laboratory, Madison, WI and the Structural Insulated Panel Association (SIPA) for providing funding and materials, respectively. Additionally, the authors would like to express appreciation to Dr. Jane Parish and the staff at Mississippi Agriculture and Forestry Experiment Station’s North Mississippi Research and Extension Center, Mississippi State University, Verona, MS.

Publisher Copyright:
© 2023, North Carolina State University. All rights reserved.


  • Bending test
  • Building products
  • Construction materials
  • Duration of load testing
  • Foam
  • Structural insulated panels (SIPs)


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