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1 The Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates t of Completion for both AIA members and non-aia members are available upon request SDPWS - Diaphragm Deflection Design John Buddy Showalter, P.E. VP, Technology Transfer American Wood Council This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Copyright 2010 American Wood Council. All rights reserved. Copyright Materials This presentation is protected by US and International Copyright laws. Reproduction, distribution, ib ti display and use of the presentation ti without written permission of the speaker is prohibited. The Wood Products Council 2010 Learning Objectives At the end of this program, participants will be able to: Participants P i t will be able to calculate l wood-frame diaphragm deflection using the 2008 SDPWS. Participants will be able to compare the difference between the 3-term and 4-term deflection equation in the 2008 SDPWS. Participants will be able to analyze individual components of the deflection equations to determine their magnitude of impact on total deflection. Participants will be able to utilize the example deflection calculation in future design work as a model for their own calculations.

2 Previous Related Webinar Outline Code acceptance of 2008 SDPWS Diaphragm Deflection Equation Diaphragm Deflection Example Code Acceptance of Standard Three-Term Term Diaphragm Deflection Equation 2009 IBC Mandatory References 2008 SDPWS in Section 2305 for lateral design and construction SDPWS Chapter 4 - Wood Diaphragms

3 Four-Term Diaphragm Deflection Equation Diaphragm Deflection Equation SDPWS Commentary Chapter 4 - Wood Diaphragms Also in 2006 IBC Bending Chord Deformation Excluding Slip Diaphragm Deflection Equation Bending Chord Splice Slip Comparison 3-term vs. 4-term Shear panel deformation and nail slip 4-term 3-term

4 Comparison 3-term vs. 4-term Comparison 3-term vs. 4-term Comparison 3-term vs. 4-term Comparison 3-term vs. 4-term Use to calculate e n

5 Comparison 3-term vs. 4-term Comparison 3-term vs. 4-term Calculated deflections at 1.4 x v s (ASD) closely match test data for blocked and unblocked diaphragms. Wood Diaphragm Deflection Example Diaphragm Dimensions and Loads 2008 SDPWS Commentary

6 Diaphragm Capacity SDPWS S Table 4.2A G a = 14 kips/in v s = 255 plf (ASD) Nominal/2.0 Chord Splice Part 1 Calculate number of 16d common nails in the chord splice Diaphragm chord: Two 2x6 No. 2 DFL E = 1,600, psi G = 0.50 Chord Splice Chord Splice Part 1 Calculate number of 16d common nails in the chord splice Z ASD = 226 lb. Part 1 Calculate number of 16d common nails in the chord splice Might need to consider M max if joint location unknown

7 Part 2 Calculate l mid-span deflection Term 1. Deflection due to bending and chord deformation Use 3-term equation Term 1. Deflection due to bending and chord deformation Strength level design loads Term 1. Deflection due to bending and chord deformation Excluding chord splice slip ASCE 7 requires that seismic story drift be determined using strength level design loads Effect of chord splice slip on chord deformation addressed in deflection equation Term 3

8 Term 1. Deflection due to bending and chord deformation Term 2. Deflection due to shear, panel shear, and nail slip Single chord assumption One top pplate designed to resist induced axial force second as splice plate. Engineering judgment. Doubling area yields G a = 14 kips/in., apparent shear stiffness (SDPWS Table 4.2A) x = 16 ft, distance from the joint to the nearest support. Each joint is located 16 ft from the nearest support. Δ c = Joint deformation (in.) due to chord splice slip in each joint.

9 = 11,737 lb/in./nail, load slip modulus for dowel type fasteners per NDS : 180,000 D 1.5 Constant of 2 used in numerator to account for slip in nailed splices on each side of joint Tension chord slip calculation Compression chord and total slip calculation Assume compression chord butt joints have a gap that exceeds the splice slip, so tension chord slip also used for compression chord

10 Total mid-span deflection Questions? Online ecourses FAQ s Helpdesk Course Evaluations In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.