David Biggs, Jason Thompson, and Arturo Schultz
i Principal, Biggs Consulting Engineering, Saratoga Springs, NY, USA, biggsconsulting@att.net
ii Owner, Coltivomae, LLC, Hamilton, VA, USA, jason@coltivomae.com
iii Professor and Director, School of Civil & Environmental Engineering, and Construction Management, The University of Texas at San Antonio, San Antonio, TX, USA, arturo.schultz@utsa.edu
ABSTRACT
In the United States, pre-insulated concrete masonry units (CMU) for single-leaf (single-wythe) have become more popular in the past decade due to their thermal performance. However, thermal considerations, coupled with broader objectives to increase operational energy efficiency, have driven the development of an array of various integrally insulated concrete masonry units that can be used with either partially grouted walls or fully (solid) grouted walls. These units were made possible by changes to ASTM C90, Standard Specification for Loadbearing Concrete Masonry Units, which now allows reduced web areas connecting the face shells. For the assemblies evaluated in this paper, the web height for the partially-grouted units is reduced only at the insulation inserts, while the full width of the webs is reduced for the fully-grouted units. In either case, however, the reduced webs increase the possibility of web shear failures. This paper will present shear testing results from research that demonstrates such reduced-web units, when reinforced and partially- or fully-grouted, exhibit performance like the design models stipulated in TMS 402, Building Code Requirements for Masonry Structures, which were originally developed for uninsulated, full web height CMU. In addition, web shear test results will be presented and compared to ASTM and TMS design criteria.
KEYWORDS: Integrally-insulated, Concrete Masonry, Shear Strength, Web Shear, Partially Grouted, Insulation Inserts.
041-Biggs.pdf
