Connectors in Concrete Used in Light-Frame Construction
The performance of cast-in-place and post-installed bolts in concrete continues to be an important issue in the concrete anchoring industry. New design provisions (ACI 318 Appendix D), referenced in the 2000, 2003 and 2006 International Building Code, are much more calculation intensive. They also typically yield much smaller design strengths and larger concrete members than previous methodologies, and require more stringent testing for cast-in-place and post-installed bolts installed in concrete when testing is performed. Cracks typically occur when concrete is in tension. ACI 318 Appendix D permits up to a 40% increase in design strength when analysis indicates there are no cracks at the anchor location at service load levels.
Simpson Strong-Tie has been working diligently to test and analyze its embedded connector products for light-frame construction to determine if some of new code methodology and requirements for cast-in-place and post-installed bolts might be applicable. Based on the lack of observed failures, our testing and analysis, and our understanding of the new methodologies for cast-in-place and post-installed bolts in concrete, we believe that most of the new code requirements for bolts should not apply to embedded connector products used in typical light-frame applications, such as foundations in one and two-story structures.
Currently, Simpson Strong-Tie is continuing its testing and analysis program for embedded connectors as well as having discussions with the ICC Evaluation Service to determine what, if any, revisions to the current load rating methodology for embedded anchorage products should be required. We will continue to keep you updated as more information becomes available.