Masonry arches

The arch has long been used in masonry structures. In fact, a brick masonry arch found in the ruins of Ur in Mesopotamia dates back to 1400 B.C. Today, the brick arch is used in construction to span over wall openings and add aesthetics, as the arch is the consummate definition of form and function.

This information addresses design considerations for brick arches in veneer construction. Common arch terminology is shown in Figure 1. below. The first important consideration when designing a brick arch is whether the arch is structural or non-structural. That is, will the arch be required to transfer vertical loads to abutments or will it be fully supported by a steel angle. While this may seem obvious, confusion often develops because of the many configurations of arch construction.

To answer this question, one must consider the two structural requirements necessary for a brick arch to adequately carry vertical loads. First, vertical loads must be carried by the arch and transferred to the abutments. Second, vertical load and lateral thrust from the arch must be resisted by the abutments. If either the arch or the abutment is deficient, the arch must be considered as nonstructural and the arch and its tributary load must be fully supported by a steel angle or plates. Alternately, reinforcement may be used to increase the strength of either or both the arch and the abutments.

This main concept in masonry arch design is overlooked, ignored or just simply not understood by nearly all home builders. Home owners ignore the problem of a failing arch only to later physically watch as these arches fall to the ground dramatically increasing the cost of repair. This defect in masonry construction is growing worse each year as fewer and fewer of today’s homebuilders or masons receive any vocational training or apprenticeship in the field.

(www.themasonryarch.com)

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