![]() ![]() The limitations based on SDC are the same as in the 2003 IBC, described above. Whereas with the 2003 IBC, the designer need only check the SDC and basic wind speed, with the 2006 IBC, to use empirical design the designer must check: The 2006 IBC further refines the empirical design limitations. A wind speed of this velocity generally applies along the East and Gulf coasts of the United States. The 2003 IBC restricts empirical design to locations where the basic wind speed (three-second gust, not fastest mile) is less than or equal to 110 mph (79 m/s), as defined in Minimum Design Loads for Buildings and Other Structures, ASCE 7 (ref. In addition, buildings that rely on empirically designed masonry walls for lateral load resistance are allowed up to 35 ft (10.7 m) in height. When laid in stack bond, the IBC requires a minimum amount of horizontal reinforcement (0.003 times the wall’s vertical cross-sectional area and spaced not more than 48 in. When empirically designed elements are part of the seismic lateral force resisting system, however, their use is limited to SDC A.Įmpirical design has primarily been used with masonry laid in running bond. The IBC allows elements of masonry structures to be designed by empirical methods when assigned to Seismic Design Category (SDC) A, B or C, subject to additional restrictions described below. For empirical design of foundation walls, see TEK 15-1B, Allowable Stress Design of Concrete Masonry Foundation Walls (ref. These empirical design requirements do not apply to other design methods such as allowable stress or limit states design. This TEK is based on the provisions of Section 2109 of the International Building Code (IBC) (ref. Using empirical design, vertical and lateral load resistance is governed by prescriptive criteria which include wall height to thickness ratios, shear wall length and spacing, minimum wall thickness, maximum building height, and other criteria, which have proven to be effective through years of experience. Empirical design has also been used extensively for the design of exterior curtain walls and interior partitions. It has proven to be an expedient design method for typical loadbearing structures subjected to relatively small wind loads and located in areas of low seismic risk. This approach to design is based on historical experience in lieu of analytical methods. Empirical provisions preceded the development of engineered masonry design, and can be traced back several centuries. ![]() Empirical design is a procedure of proportioning and sizing unreinforced masonry elements based on known historical performance for a given application. ![]()
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