For reinforced masonry, compression and tension stresses in the reinforcement below the specified yield strength, f y, are taken equal to the modulus of elasticity of the reinforcement, Es, times the steel strain ε s. The maximum usable strain, ε mu, at the extreme compression fiber of concrete masonry is 0.0025. The maximum masonry compressive stress is 0.80 f’ m for both reinforced and unreinforced masonry. The nominal strength of masonry cross-sections for combined flexure and axial load is based on applicable conditions of equilibrium. The units, mortar, grout and reinforcement for reinforced masonry act compositely to resist applied loads. For reinforced masonry, the tensile strength of the masonry is neglected when calculating flexural strength, but considered when calculating deflection. For unreinforced masonry, the flexural stresses in the masonry are assumed to be directly proportional to strain. Therefore, strain in the masonry and in reinforcement, if present, is directly proportional to the distance from the neutral axis. Plane sections before bending remain plane after bending. 1, 3, 5), as shown in Figure 1 for a reinforced element: Strength design is based on the following design assumptions in conjunction with basic principles of engineering mechanics (refs. Tables, charts, and additional design aids specific to the design of various concrete masonry elements can be found in other related TEK. 6), and TEK 14-7A, Allowable Stress Design of Concrete Masonry (ref. 5).įor empirical and allowable stress design requirements, the user is referred to TEK 14-8A, Empirical Design of Concrete Masonry Walls (ref. MASONRY STACK BOND IN SEISMIC CATEGORY CODE
4) are also reviewed, as are modifications included in the 2008 MSJC Code (ref.
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3) through Section 2108 of the 2006 International Building Code (ref. In addition, changes to the strength design method incorporated into the 2005 edition of the MSJC Code (ref. 1) as referenced and modified in Section 2108 of the 2003 International Building Code (IBC) (ref. This TEK provides a basic overview of design criteria and requirements for concrete masonry structures designed using the strength design provisions contained in Chapter 3 of the 2002 edition of Building Code Requirements for Masonry Structures (also referred to as the MSJC Code) (ref. 1): empirical design, strength design or allowable stress design. Concrete masonry elements can be designed using one of several methods in accordance with Building Code Requirements for Masonry Structures (ref.
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