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<title>Diaphragm (structural system)</title>
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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Diaphragm (structural system)</span></span>
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<p>In <a href="Structural_engineering" title="Structural engineering">structural engineering</a>, a <b>diaphragm</b> is a structural element that transmits lateral loads to the vertical resisting elements of a structure (such as <a href="Shear_wall" title="Shear wall">shear walls</a> or <a href="Framing_(construction)" title="Framing (construction)">frames</a>). Diaphragms are typically horizontal but can be sloped in a gable roof on a wood structure or concrete ramp in a parking garage. The diaphragm forces tend to be transferred to the vertical resisting elements primarily through in-<a href="Plane_(mathematics)" title="Plane (mathematics)">plane</a> <a href="Shear_stress" title="Shear stress">shear stress</a>.<sup id="cite_ref-:0_1-0" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The most common lateral loads to be resisted are those resulting from <a href="Wind" title="Wind">wind</a> and <a href="Earthquake" title="Earthquake">earthquake</a> actions, but other lateral loads such as <a href="Lateral_earth_pressure" title="Lateral earth pressure">lateral earth pressure</a> or <a href="Hydrostatic_pressure" class="mw-redirect" title="Hydrostatic pressure">hydrostatic pressure</a> can also be resisted by diaphragm action.
</p><p>The diaphragm of a structure often does double duty as the <a href="Floor" title="Floor">floor</a> system or <a href="Roof" title="Roof">roof</a> system in a <a href="Building" title="Building">building</a>, or the <a href="Deck_(bridge)" title="Deck (bridge)">deck</a> of a <a href="Bridge" title="Bridge">bridge</a>, which simultaneously supports gravity loads.<sup id="cite_ref-:0_1-1" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>Parts of a diaphragm include:<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup>
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<ul><li>the collector (or membrane), used as a shear panel to carry in-plane shear</li>
<li>The drag strut member, used to transfer the load to the shear walls or frames</li>
<li>the chord, used to resist the tension and compression forces that develop in the diaphragm since the collector is usually incapable of handling these loads alone</li></ul>
<p>Diaphragms are usually constructed of <a href="Plywood" title="Plywood">plywood</a> or <a href="Oriented_strand_board" title="Oriented strand board">oriented strand board</a> in <a href="Timber_framing" title="Timber framing">timber</a> construction; <a href="Metal" title="Metal">metal</a> deck or composite metal deck in <a href="Structural_steel" title="Structural steel">steel</a> construction; or a <a href="Concrete_slab" title="Concrete slab">concrete slab</a> in <a href="Reinforced_concrete" title="Reinforced concrete">concrete</a> construction.<sup id="cite_ref-:0_1-2" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>
</p><p>The two primary types of the diaphragm are flexible and rigid.<sup id="cite_ref-:0_1-3" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Flexible diaphragms resist lateral forces depending on the tributary area, irrespective of the flexibility of the members to they are transferring force to. On the other hand, rigid diaphragms transfer load to frames or shear walls depending on their flexibility and their location in the structure. Diaphragms that cannot be classified as either flexible or rigid are referred to as semirigid.<sup id="cite_ref-:0_1-4" class="reference"><a href="#cite_note-:0-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The flexibility of a diaphragm affects the distribution of lateral forces to the vertical components of the lateral force-resisting elements in a structure.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>
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<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
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<li id="cite_note-:0-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-:0_1-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-:0_1-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-:0_1-4"><sup><i><b>e</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
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</style><cite id="CITEREFAdams" class="citation web cs1">Adams, Allen. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20240506223820/https://www.thestructuralengineer.info/education/structural-analysis/structural-stability/diaphragms">"Diaphragms"</a>. <i>www.thestructuralengineer.info</i>. Archived from <a rel="nofollow" class="external text" href="https://www.thestructuralengineer.info/education/structural-analysis/structural-stability/diaphragms">the original</a> on 2024-05-06<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-05-06</span></span>.</cite></span>
</li>
<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><cite id="CITEREFMaloneBrenemanRice2022" class="citation book cs1">Malone, Terry R.; Breneman, Scott E.; Rice, Robert W. (2022). "Drag Struts and Collectors". <i>Analysis of Irregular Shaped Structures: Wood Diaphragms and Shear Walls</i> (2nd ed.). New York: McGraw Hill. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9781264278824</bdi>.</cite></span>
</li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite id="CITEREFRoskelley2010" class="citation book cs1">Roskelley, Blake Alan (2010). <i>An Investigation of the Influence of Diaphragm Flexibility on Building Design Through a Comparison of Forced Vibration Testing and Computational Analysis</i>. San Luis Obispo, California: California Polytechnic State University. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.15368%2Ftheses.2010.164">10.15368/theses.2010.164</a>.</cite></span>
</li>
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