Reinforced Masonry ASD (MSJC Section 2.3.5): Flexural members:Īllowable shear stress without shear reinforcement (Ref 1 Section 2.3.5.2.2):Īllowable shear stress with shear reinforcement (Ref 1 Section 2.3.5.2.3):Īllowable shear stress is based on the ratio of M/(V*d) where M=moment V=shear force and d=depth from extreme compression fiber to tension reinforcement
MASONRY STACK VS CODE
However, in 2011 the MSJC, the code states (section 8.2.6.3) that the minimum normalized web area shall be 27 in^2/ft which provides sufficient web area so that hte shear stresses between the web and face shell of a unit will not be critical for out of plane loading.Īllowable shear stress without any reinforcement (Ref 1 Section 2.3.5.2.2): This is shown above for In-Plane shear forces. In MSJC 20 the commentary suggested that section 2.2.5.2 be used due to the absence of suitable research data. Out-of-plane Shear Forces (Ref 1 Commentary 2.2.5): 60 psi + 0.45 (For running bond masonry grouted solid).37 psi + 0.45 (For stack bond masonry with open end units and grouted solid).37 psi + 0.45 (For running bond masonry not grouted solid).Unreinforced Masonry ASD (MSJC Section 2.25) In-plane Shear Forces (shear walls):Īllowable shear stress without any reinforcement (Ref 1 Section 2.2.5.2): Base the allowable stress a reinforced wall section (flexural member or shear wall as applicable). If there is net tension and the wall is reinforced (with longitudinal reinforcement for bending stress) then find the shear stress using fv=V/(b*d). Then base the allowable stress on an unreinforced masonry section (not to be confused with a reinforced section w/out reinforcement). P/A-M/S, is the stress negative)? If no then calculate the shear stress using fv = VQ/In*b where V=shear force, Q=first moment of area, In= net section moment of inertia and b=width or thickness of section. Here are the basics – Is the section subjected to a net flexural tension stress (i.e. However make sure that you are only multiplying the end result and not f’m found in the equations and the end result. Also allowable stress may be multiplied by 4/3 for short term loads – wind and earthquake per ASCE7-05 C2.4.1. MSJC-08 provides a flowchart for shear design in the commentary (Figure CC-2.3-2) which is very helpful. Unreinforced Masonry – STR (Strength Design).Unreinforced Masonry – ASD (Allowable Stress Design).There are several design methods / configurations to consider. This will be a more indepth look at shear forces and how they are handled in masonry design and analysis. Found here Design and Analysis of Masonry Subject to Shear Forces MSJC 2008 (2005 is very similiar however these provisions change for 2011) Building Code Requirements and Specification for Masonry Structures and Related Commentaries (AKA TMS 402 or ACI 530). I will keep updating this for strength design and include some further discussion in the near future. In addition, this guide does not address the design or construction of unreinforced dry-stack masonry systems or segmental retaining wall systems.For right now I am going to cover basic shear design in accordance with MSJC 2005 / 2008 (AKA TMS 402/ACI 530). Because veneer systems do not function as part of the structural system, they are not included in this guide. There are dry-stack masonry systems specifically intended for veneer applications.
MASONRY STACK VS DOWNLOAD
Other Available Formats: Protected Download (Single-User)ĭesign and Construction Guidelines for Dry-Stack Concrete Masonry was developed by The Masonry Society’s Design Practices Committee as a non-mandatory aid for designers, building officials, contractors, educators, and others interested in dry-stack masonry construction. Because the majority of dry-stack research has been limited to reinforced or prestressed concrete masonry construction, the scope of this guide is limited to reinforced or prestressed, dry-stack construction of concrete masonry units. Despite its historical use, there is little in the way of contemporary design and construction guidance in the United States on the use of dry-stack masonry systems for structural applications. Among the subjects covered are history and background, fire resistance, design, construction, quality assurance, materials, surface-bonding, placement of embedded items, analysis, strength and serviceability, flexural and axial loads, shear, details and development of reinforcement, walls, and seismic design requirements.ĭry-stack masonry construction, which consists of individual masonry units placed without the use of mortar in the head and bed joints, is one of the earliest forms of construction.
This guide covers the design and construction of dry-stack concrete masonry structures constructed from hollow units.
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