In these cases, the length should be greater than or equal to the height of the specimen. In some situations, the length requirement for a specimen may not be able to be attained. The coupon must meet the specimen size requirements of a height to thickness ratio equal to two (2) to one (1) and a length to thickness ratio equal to four (4) to one (1). Due to their unique configuration full-size testing of screen wall block is not feasible, thus requiring that coupons be removed from the screen wall block for compressive strength testing. Verification of unit properties should be in accordance with ASTM C140, Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units, Annex A1 (Ref. At a minimum, concrete masonry units used for screen walls should meet the requirements of ASTM C90, Standard Specification for Loadbearing Concrete Masonry (Ref. Note that these unit configurations can come in various thicknesses depending upon availability.ĭespite screen wall units being used predominately in non-loadbearing applications, they still should be of high quality for their intended construction. Figure 1 illustrates a general overview of some of the shapes that may be encountered for screen wall design. Screen Wall Units – Due to the virtually limitless number of shapes and sizes for concrete masonry screen wall units, designers are encouraged to check on the availability of any specific shape during the early planning stages of a project. Some shapes are available only in certain localities and others may be restricted by patent or copyright. Strength and stability is provided by: (1) incorporating steel reinforcement (either conventional reinforcing bars, bed joint reinforcement, and/or anchors) (2) limiting the clear span of screen walls and/or (3) providing a separate support system capable of carrying lateral loads from the assembly to the backup support(s). Screen walls should be designed to resist wind pressure and seismic forces to which they are exposed to while providing a durable and attractive architectural finish. The open area is created usually by the use of special screen units with decorative openings in their face. 5).Įxtra attention to the design of screen walls is warranted because of the relatively high percentage of open area in their face. For loadbearing screen wall applications, users are referred to the applicable engineering analysis provisions of TMS 402 (Ref. The scope of this TEK focuses on the design and detailing of non-loadbearing concrete masonry screen walls. Curtain walls, fences, sun screens, and room dividers are just a few of the limitless applications for a concrete masonry screen wall. Created originally as a functional building element, the screen wall combines privacy with observation, interior light with shade and solar heat reduction, and airy comfort with wind control for both interior and exterior applications. Concrete masonry screen walls are used in every part of every country on the globe, on every conceivable style of building, and for a wide variety of purposes.
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