It has evolved into our present-day Building Code Requirements for Masonry Structures (ref. This served as the building code for engineered concrete masonry structures and was adopted by the Southern Building Code Congress and other model codes. A major milestone in the advancement of engineered concrete masonry was the establishment of the Specifications for Design and Construction of Load Bearing Concrete Masonry by NCMA in the late 1960’s (ref. Slots manufactured into the webs of units (termed bond beam units) are used to position horizontal reinforcement within the wall.Ĭoncrete masonry is widely used because of the strength, durability, economy, architectural appeal, and versatility of the masonry system. Open end units, with one or both end webs removed, permit the placement of units around vertical reinforcing bars. Special unit shapes are manufactured to accommodate reinforcement. The modular nature of concrete masonry units makes construction straightforward and the small unit size makes changes in plan or elevation easy. Today there are many examples of loadbearing masonry buildings up to 15 to 28 stories high. In the late 1940’s, one of the first examples of engineered multistory construction was used by Professor Paul Haller in Switzerland. These new manufacturing processes allowed concrete masonry to be used in engineered structural systems such as multistory load-bearing structures. Initially, these units were made with hand-operated equipment, although by the 1940’s, block production had developed to incorporate automated mixing, molding, and curing methods, resulting in consistent quality of materials. Concrete masonry units, however, are a relatively recent innovation. Masonry structures have been used for centuries throughout the world.

Concrete building construction process