Shear friction can govern with shear-dominated walls. However, these long walls big box structures are generally governed by architectural requirements and not structural requirements; there is usually more than sufficient structural strength. Figure 3 provides Shear Friction Design equations.
There were two major changes to the anchor bolt provisions. This increase was based on examining anchor bolt tests. The average ratio of experimental strength to nominal strength was 2. The change still results in a conservative prediction of nominal strength, with the average ratio of experimental strength to nominal strength being 1.
A similar change was made to Allowable Stress Design. The second change was to the interaction between the tensile and shear strength of anchor bolts. Previously, there was a linear interaction diagram. These two changes, coupled with a change in ASCE that reduces the minimum design strength of anchors not governed by tensile yielding or shear yielding from 2.
Increased energy requirements for building envelopes has resulted in wider cavities in brick veneer walls to accommodate increased insulation thicknesses. Joint reinforcement with cross and longitudinal wires of size W2. Anchor capacities of adjustable anchors are primarily controlled by bending of the pintles at a maximum allowed offset of 1. This capacity is independent of cavity width and is not affected by the code change.
The requirements for anchors for increased cavity widths have compression capacity that equals or exceeds current requirements. TMS has provisions for distributing concentrated loads in walls based on a 2 vertical to 1 horizontal dispersion terminating at half the wall height, or the edge or opening of a wall.
This resulted in very small distribution lengths for concentrated loads near the edge of a wall and no dispersion for loads at the edge of a wall or an opening. This could result in unconservative designs as the axial load generally increases the moment capacity. A provision was added that a concentrated load could be distributed at 3 vertical to 1 horizontal on one side of an opening. This steeper dispersion will continue away from the opening up to one-half the height of the masonry below the load so that the dispersions can be truncated independently on each side of the bearing Figure 4.
Other technical changes include deleting the prescriptive requirements for masonry piers in strength design, as most of the requirements were redundant with the current prescriptive seismic design. Design Tools. It typically takes several years for jurisdictions to adopt the latest edition of the IBC, so it will be a few years before the code is legally adopted. However, there are some changes that will benefit masonry designers and mason contractors, and with approval from the local building authority, those can be implemented now.
The next edition of the code will be in six years instead of three, or in This change recognized the burden on the industry when codes change too frequently and has been welcomed by designers and contractors. One change relates to the first course of masonry. In addition to technical updates, there were four non-technical changes. The second change is that the code has six fewer pages than the edition, being one of the few structural codes that have fewer pages than the previous edition Figure 2.
The third change was to incorporate user-friendly tables rather than text throughout the document. The fourth change is not a direct revision to the edition; TMS has approved a six-year code cycle, so the next TMS code will be the edition.
A significant technical change was the addition of shear friction provisions. Walkowicz, PE, N. This presentation is protected by US and International copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited.
Many revisions and enhancements have been made to the Building Code Requirements and Specification for Masonry Structures including: a complete reformatting of the document into a more user friendly format the addition of an Appendix on an optional limit design method for special reinforced masonry shear walls a new Chapter for the prescriptive design of masonry partition walls movement of the empirical provisions into an Appendix a change to permit a moment magnifier approach for the design of reinforced clay, concrete masonry and autoclaved aerated concrete AAC masonry walls revisions of design requirements for partially grouted shear walls changes to the requirements for joint reinforcement and seismic clips for anchored veneer in SDC D, E, and F.
About The Masonry Society Formed in , The Masonry Society TMS is an educational, scientific, and technical society dedicated to the advancement of scientific, engineering, architectural, and construction knowledge of masonry.
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