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Addendum to Memorandum "Lesvna Remodel — Beam and Foundation Chan�es", dated 5/23/2014
<br />To: City of Everett Building Inspector, and Jeff Heilman, City of Evertt
<br />From: Mark Lesyna, owner of 3709 Shore Ave
<br />Date: 7/16/2014
<br />Plan Check No: C1311-005
<br />Calculation of the maximum allowed span between the basement beam posts at 3709 Shore Ave
<br />• This analysis is based on the code limits for deflection (L/240 for DL + LL), as prescribed by Geoff in the
<br />referenced 5/23/14 memo.
<br />• The basement I beam is W5x19 per A992, a wide flange steel I-beam with these properties:
<br />o E = 3.6x10' psi
<br />o Ixx = 26.2 Ill4
<br />o Self Weight = 19 Ibs/ft
<br />• The basement beam carries two line loads from the 2"d floor. Those are supported with posts directly under
<br />the load. The portions of the beam with a span therefore only carry loads from the main floor.
<br />• The beam carries loads from a 12' width of the main floor, at 10 Ibs/sqft DL + 40 Ibs/sqft LL.
<br />Beam loading w= 12 ft *(10+40) Ibs/sqft + 19 Ibs/ft self weight = 620 Ibs/ft uniform load.
<br />• The portions of the beam with a span are located with a support at least 20" from the end of the beam with
<br />a second support at the end. Therefore the beam has fixed end supports (rather than simple end support if
<br />the span begins at one end of the beam). From Roark's Formulas for Stress and Strain 6th edition (shown
<br />below): The maximum deflection for a uniformly loaded beam with fixed-fixed supports occurs at half span
<br />and is Max Y = —W��4
<br />384*E*/
<br />.
<br />From Roark's Formuias for Stress and Strain. 6th Edition.
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<br />Substituting Ymax = L/240 and solving: L,,tax = = 25 ft, 8 inches
<br />z4o*w
<br />For that maximum span, Ymax = L/240 = 1.28 inches
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<br />Thus spans up to Lmax = 25 ft, 8 inches are allowed. The maximum span in use is <14 ft, thus Ymax is 0.11 inches.
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