Concrete Masonry Unit Geometry for Improved Structural Efficiency, Sustainability, and Constructability
The Workplace Safety and Insurance Board of Ontario reports that the masonry rate group cost per insurance claim is 2.44 times that if all other construction class rate groups. Manual lifting of concrete masonry units is required for masonry construction, and the pay masons receive is often commensurate with the number of units laid per day. Researchers have shown that, when lifting concrete masonry units, lower back compression forces in masons exceed the specific safe action limit despite the fact that the manual lifting load cutoff is not exceeded. This suggests that some handling techniques are unsafe, but can be mitigated if the weight of the units can be decreased. A change to unit geometry can also reduce thermal bridging and increase insulation power and so improve the sustainability of masonry construction. A re-examination and revision of concrete masonry unit geometry is therefore proposed.