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	<h2>Moment Frame Design Requirements and Assumptions</h2>
	
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			<h4>Connection Design</h4>
			
			<p>
				The Strong Frame special moment frame using the Yield-Link&reg; structural fuse incorporates the capacity-based design approach, wherein energy dissipation is confined predominantly within the reduced region of the Yield-Link structural fuse. Member and connection design is based on the maximum probable tensile strength, Pr-link, of the reduced region of the Yield-Link (see Figure 1).
			</p>
<p style="max-width: 80%; margin: 20px auto 0; text-align: center;">
				<strong>Figure 1 &mdash; Yield-Link Design for Energy Dissipation</strong>
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<p style="max-width: 80%; margin: auto; text-align: center">
				<strong>(a) Design Parameters</strong>
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			<img style="display: block; margin: 40px auto 20px; max-width: 80%; height: 200;" src="https://embed.widencdn.net/img/ssttoolbox/yysepeieiw/2048x650px/F-L-SFDG20-35a-2020.png" alt="SMF Connection Design, Figure 1(a) - Design Parameters">
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<p style="max-width: 80%; margin: auto; text-align: center;">
				<strong>(b) Yield-Link Stretching and Shortening from Testing</strong>
			</p>
			<img style="display: block; margin: 20px auto; max-width: 50%; height: 200;" src="https://embed.widencdn.net/img/ssttoolbox/tdcduycjfi/exact/F-L-SFDG20-35b-2020.png" alt="SMF Connection Design, Figure 1(b) Yield-Link Failure Mode">
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			<p>
				The following are steps for the Strong Frame connection design:
			</p>
			
			<ol>
				<li>Model and analyze moment frame with Yield-Link&reg; moment connections to get demand loads (moment, shear and axial) using code level forces.</li>
				<li>Design Yield-Link yielding area to resist the maximum axial force from all the standard LRFD load combinations. This means our Yield-Links are designed to remain elastic under code force load combinations including lateral plus gravity loads.</li>
				<li>Once the yielding area is known, calculate the maximum rupture strength, P<sub>r-link</sub> , of the Yield-Link as:</li>
					<ul class="no-style">
						<li style="padding-left: 40px;">P<sub>r-link</sub> = A<sub>y</sub>-link x R<sub>t</sub> x F<sub>u-link</sub></li>
						<li>Where
							<ul class="no-style">
								<li>A<sub>y-link</sub> = area of reduced Yield-Link section, in.<sup>2</sup></li>
								<li>Rt = ratio of expected tensile rupture strength to minimum tensile stress of the link stem material, 1.2</li>
								<li>Fu_link = specified minimum tensile strength of link stem material, 65 ksi</li>
							</ul>
						</li>
						<li>It is worthwhile to point out that we are using R<sub>t</sub> and F<sub>u</sub> for this calculation where other SMF connections typically use R<sub>y</sub>, F<sub>y</sub> and a C<sub>pr</sub> factor that is less than or equal to 1.2. Using R<sub>y</sub> of 1.1, R<sub>t</sub> of 1.2, F<sub>y</sub> of 50 ksi, Fu of 65 ksi and C<sub>pr</sub> of 1.2. The difference in demand can be seen below:
							<ul class="no-style">
								<li>Simpson Strong-Tie Strong Frame SMF Connection Design Demand: 1.2 x 65 ksi = 78 ksi</li>
								<li>Standard SMF Connection Design Demand: 1.1 x 50 ksi x 1.2 = 66 ksi</li>
							</ul>
						</li>
						<li>The reason for this approach is to truly capture the ultimate strength of our Yield-Link structural fuse, since we want to make sure this is the only region where inelastic action occurs.</li>
					</ul>
				</li>
				<li>After P<sub>r-link</sub> has been determined, design the rest of the connection to exceed this P<sub>r-link</sub> demand load:
					<ul class="no-style">
						<li>a. Yield-Link stem-to-beam flange connection bolts</li>
						<li>b. Yield-Link flange-to-column flange connection bolts</li>
						<li>c. Yield-Link-flange thickness to prevent prying</li>
						<li>d. Beam-to-column shear tab connection</li>
						<li>e. Column panel zone</li>
						<li>f. Column flange thickness</li>
						<li>g. Stiffener/continuity plate (if required)</li>
					</ul>
				</li>
			</ol>
		</div>
	</div>

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