Masonry Magazine April 1985 Page. 13
Lackey
Thoren
Plumb
Derk
MCAA CONFERENCE
continued from page 11
Amrhein showed a movie and slides on pioneering research on tall, slender reinforced masonry walls recently conducted by the Western States Clay Products Association in conjunction with the Structural Engineers Association of Southern California and the Southern California Chapter of the American Concrete Institute.
Amrhein explained that the Uniform Building Code h/t (height to thickness) limitation of 25 was imposed due to lack of experimental data and an attempt to limit flexural stresses under wind load. "Because of this unnecessary h/t code restriction, it was decided to conduct a research program to demonstrate that loadbearing masonry walls can be built and be structurally safe when they exceed the slenderness ratio of 25," Amrhein said.
In the testing program, 32 test specimens were built, consisting of 10 concrete block, six clay brick, four clay block, and 12 concrete tilt-up panels. All test panels, except one, were 24'8' high and 4'0" wide. The masonry panels were reinforced with five #4 bars and the concrete panels with four #4 bars of ASTM A615 Grade 60 steel. All masonry panels were solid grouted.
Tests showed there is no limitation for the slenderness (h/t) ratio except as limited by maximum lateral deflection and strength of the wall, Amrhein said. The results are that taller and thinner masonry walls provide many user benefits, including initial cost savings, increased interior space and more vertical clearance.
Bill Dorrigan related his law firm's experience in handling litigation cases against Dow Chemical Co., producers of Sarabond high-strength mortar. The product was developed by Dow in the early 1960s for use in the fabrication of brick panels in highrise construction.
The First Wisconsin Bank Building of Green Bay, one of several Stacker & Ravich clients who have sued Dow, recently received a favorable settlement after claiming that Sarabond caused cracks in the building's facade. The bank contended that Sarabond deteriorates after construction and frees a chemical that accelerates corrosion of imbedded steel that is in contact with the mortar.
Dorrigan's firm represents several other building owners throughout the country who have similar Sarabond problems. He estimates that 20 to 30 lawsuits involving structural problems are pending against Dow.
Following Dorrigan's remarks, Walter Derk presented the insurance industry's position in cases involving product liability. "Insurance companies deal mainly with accidents and damage to property, and just won't respond to cases such as Sarabond," he said. "There is little hope
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George A. Miller (top, left) received the Canadian Masonry Contractor Association's Outstanding Achievement Award from CMCA president
Rudy Frahm during CMCA's Annual Conference at the Hilton. (Right) A scene from MCAA's Annual Meeting of the membership.
MASONRY-MARCH/APRIL, 1985 13