Ground Breaking: What Everyone Needs to Know About Wood Structural Panel Performance

Originally published by: SBCRIJune 28, 2012

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As most everyone is aware, the lateral bracing sections of the International Residential Code (IRC) and International Building Code (IBC) are challenging to understand and implement. This is particularly true with respect to the IRC. Qualtim, in concert with the Structural Building Components Research Institute (SBCRI), has undertaken $1.43 million worth of testing, analysis and finite element modeling of braced wall panels (BWP) in SBCRI’s 12' x 30' building and single-element testing stations. This work was undertaken to understand real BWP resistance, from a code compliance point of view, and to provide a foundation for evaluating equivalent performance, where Wood Structural Panels (WSP) are the benchmark code defined resisting elements. 

This work resulted in the creation of the following table. It summarizes the current publicly available test data and the various factors that need to be applied to the test data to match up with the current code defined Nominal Unit Shear Capacity (NUSC) values that provide IRC and IBC/SDPWS lateral resistance.

The NUSC values in the yellow highlighted cells are created from the publicly available data, which have been confirmed through SBCRI testing.

SUMMARY TABLE

View Table

The goal with this work is to transparently outline the fundamental test data that defines the actual real-world WSP lateral resistance. This work also defines the implied factors that allow the use of better-than-tested WSP NUSC lateral resistance values to be codified into law.

For all of the publicly available test data and related background material we have used in our work, Qualtim/SBCRI confirmation and comparative equivalency testing PowerPoint presentations, IRC/SDPWS/IBC/WFCM code compliance engineering evaluations, and graphics of our finite element analysis that aided our engineering evaluations, please visit our Braced Wall web page.

Our Qualtim/SBCRI work was undertaken to better understand BWP lateral resistance because, when we began proprietary testing, we found test results that were confounding and incompatible with current law. This led us to the strong belief that there was a very un-level playing field. Our goal then became to find ways to use benchmarking data to aggressively help all clients working with Qualtim/SBCRI to fairly compete in the market place of engineering innovation and actual lateral resistance performance. We believe that we have solid testing and analytical data to support our approach. Until data is brought to the table that shows that we are wrong, we will use our data to aggressively support engineering innovation of all companies that are like-minded.