309
3640.063
Low, Say-Gunn; Maher K. Tadros; Amin Einea; Magdi A. Khalifa; Ahmed E. Magzoub; Ervell Staab
Lightweight High Performance Concrete Masonry Units
Book
University of Nebraska, Lincoln
1993
Probably 1993-1995
1-25
Y
This paper presents the shape optimization of an 8x8x16-in. concrete masonry units (CMU). It is the result of a research project titled, “Ultra-Light High Performance Concrete Masonry Units,” conducted at the University of Nebraska in 1991-1993.Preliminary shape of the unit was established prior to detailed stress analysis. An open-end (A-shape) unit was selected to facilitate construction without the need for “threading” the unit through pre-placed vertical reinforcement. A 7/8-in. minimum thickness was used for both cross-webs and face shells taking into consideration the production of the unit, placement of horizontal reinforcement and laying of the unit at the site. The middle web was positioned to align vertically so that the group can easily fill grouted cells, and the mortared cross webs can provide for adequate dams to prevent grout from filling adjacent cells in a partially grouted wall.
Two-dimensional finite element analysis (FEA) was conducted to determine critical stress regions and magnitude of tensile stresses. Fillets were added in high tensile stress regions to redistribute the stresses. Testing was conducted to establish the compressive strength, tensile strength, and flexural strength of the optimized unit. Issues on the transportation, handling, durability, and texture of the new unit are addressed.