Masonry Magazine July 2001 Page. 14
DESIGN CONSIDERATIONS
The masonry standard used for the design and construction requirements of structural brick systems is AC1530-99/ASCE 5-99/TMS 402-99, "Building Code Requirements for Masonry Structures". This standard is commonly referred to as the "MSJC Code" (Masonry Standards Joint Committee).
Reinforced load bearing brick buildings are acceptable by all of the current model building codes (UBC, BOCA, SBC, and CABO) as well as the new International Residential Code for One and Two Family Dwellings IRC 2000 when designed in accordance with Engineered provisions of the MSJC Code.
Load bearing brick buildings with walls equal to or greater than 6 inches in nominal thickness may be designed in accordance with the empirical provisions of the MSJC Code. However, empirical provisions can typically not be used for buildings greater than one story in height or in high wind or seismic areas. In these instances engineered design would be required.
Consideration of the building layout during the design stage can help to simplify the construction. Building dimensions (wall lengths and door and window openings) should be laid out in increments of the brick units width whenever possible. This helps reduce cutting of brick units and makes the work easier for the mason.
Brick manufacturers can also help contractors and design professionals with their structural brick projects. "Our commitment to structural brick goes beyond just making the brick. We also provide engineering support, a structural design manual, privacy wall designs, house plan ideas, detailed technical literature, and computer design software for qualified professionals," said Bob Propes, Director of Promotions and National Accounts at General Shale Brick.
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SELECTION OF MASONRY UNITS
Reinforced structural brick construction utilizes hollow clay units, which are manufactured in accordance with the requirements of ASTM C652, Specification for Hollow Brick. These units are manufactured with cells which can accommodate vertical reinforcement and grout. Bond beam units are also available, which are used for supporting ledger boards at floor connections and at the top of a wall for support of the sole plate and roof truss system. Bond beams are also used to build reinforced beams or lintels over window and door openings. Reinforced masonry beam lintels with nominal amounts of reinforcement steel can easily span 18-foot garage door openings without the use of a steel angle.
There are a variety of sizes of structural brick units manufactured today. Hollow units are available in nominal widths of 4 inches, 5 inches, 6 inches, and 8 inches. For residential and light commercial construction, the 5 inch and 6 inch nominal units are the most common. While 8 inch units are generally used for larger