May 1998
Executive Summary
Historically, cast-in-place concrete for residential construction has been primarily limited to below grade applications such as footings and foundation walls. Such construction was relatively labor intensive, and, therefore was not considered a viable alternative for other parts of the building. However, the recent advent of insulating concrete form (ICF) wall construction has resulted in a competitive and energy efficient alternative for above grade walls in residential construction.
The purpose of this Lintel Testing for Reduced Shear Reinforcement in Insulating Concrete Form Systems program is to investigate the structural capacity and performance of the concrete lintels typically used in ICF construction. Lintels are reinforced concrete structural elements that support loads above openings in concrete walls. Shear reinforcement is generally difficult to install in ICF systems and, therefore, adds to the construction costs.
The major goal of the testing program is to support the development of economical lintel designs for ICF construction by eliminating shear reinforcement when feasible. An analysis was conducted to evaluate the current lintel design provisions in ACI 318-95. Experimental studies, on various configurations of ICF lintels, were conducted to further evaluate existing design provisions and determine whether certain restrictive provisions could be waived for ICF lintels in typical residential construction applications.
Additional experimental and analytical work is recommended to expand this cost-effective benefit to ICF lintels that are longer in span.
Prepared for:
The U.S. Department of Housing and Urban Development
Office of Policy Development and Research
Portland Cement Association
National Association of Home Builders
26 pages