mass timber framing systems structural design of...structural design of mass timber framing systems...
TRANSCRIPT
structural design ofmass timber framing systems
nwwood designsymposium -seattle davinlewis, p.e., p.eng.fast +epp july19,2018Disclaimer: This presentation was developed by a third party and is not
funded by WoodWorks or the Softwood Lumber Board
This presentation is protected by US and International Copyright laws. Reproduction, distribution, display and use of the presentation without
written permission of the speaker is prohibited.
© Fast + Epp 2018
Copyright Materials
“The Wood Products Council” is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES), Provider #G516.
Credit(s) earned on completion of this course will be reported to AIA CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.
This course 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.
coursedescription
Mass timber structural framing systems have highstrength-to-weight ratios, are dimensionally stable, and arequickly becoming systems of choice for sustainablyminded designers. This presentation will provide a detailedlook at the structural design processes associated with avariety of mass timber products, including glued-laminatedtimber (glulam), cross-laminated timber (CLT), and nail-laminated timber (NLT). Applications for the use of theseproducts in gravity force-resisting systems under modernbuilding codes will be discussed. Other technical topics willinclude use of mass timber panels as two-way spanningslabs, connection options and design considerations, anddetailing and construction best practices.
learningobjectives
At the end of this course, participants will be able to:
1. Discuss mass timber products and building systems andtheir possibilities as structural framing.
2. Compare structural properties and performancecharacteristics of mass timber products and review theirunique design considerations.
3. Review structural design steps for members andconnections in commonmass timber framing systems.
4. Highlight structural detailing best practices to address itemssuch as shrinkage and expansion, load path continuity, andspeed of construction.
aboutour firm+ Vancouver | Canada+ Frankfurt | Germany+ New York | USA+ Seattle | USA+ Edmonton | Canada
strengthto weight
compression 1 2.3 3.4
tension 1 28 16
5,000 psi A36 SPFconcrete steel No.2
woodproperties
stiffness
5,000 psi A36 SPFconcrete steel No.2
stiffnessto weight 1 2.2 2.0
modulus ofelasticity 1,000 – 2,000 ksi
woodproperties
woodproperties
shrinkage andswellingIllu stratio n C re dit: G e o ff’s W o o dw o rk
S o u rce : U S Fo re st P ro du cts Lab o rato ry
structuralspecifications
designstandardscommon “holes”
mockupsdelegated design itemsweather protectiontolerancessealers
(coordinate with Division 09)
designchecks
gravityframing
strengthaxialbendingshearbearingpost-fire?
serviceabilitydeflections
(including creep)vibrations
gravityframing
decks
nail-laminated timber (NLT)
glulam panels (GLT) wood-concrete
composites
cross-laminated timber (CLT)
structural composite lumber (LSL, LVL)
plankdecking
NLTdesign
2x “joists”at 38mm (1-1/2”)
gravityframing
choose:depth, profilespecies, grade
continuousvs. butt-jointedlaminations
CLTdesign
gravityframingdimensional stability
APA PRG 320defines structural grades
panel sizes vary by supplier
cross laminationsreduce strength and stiffnessin primary span direction
decisionsdecisions...
NLT may be most appropriate if:floor structure spans one wayfloor structure is curved in one directionbudget is tightstructure is an addition or alteration to an existing
building (no crane access from above)a less “manufactured” aesthetic is desired
gravityframing
decisionsdecisions...
GLT may be most appropriate if:floor structure spans one wayspans are long (no strength/stiffness reduction as
for NLT with butt joints)a clean aesthetic is desired
gravityframing
decisionsdecisions...
CLT may be most appropriate if:floor structure needs to span in two directions
(e.g. weak-axis cantilevers)a clean aesthetic is desiredaccommodating shrinkage and swelling during
construction is difficulttight tolerances are required
gravityframing
typicalspans
gravityframing
2x4 NLT, 3” GLT, 3-ply CLT (4” ±)≤ 12’≤ approx. L/40
2x6 NLT, 5” GLT, 5-ply CLT (7” ±)10’ – 17’approx. L/20 to L/40
typicalspans
gravityframing
2x8 NLT, 7” GLT14’ – 21’approx. L/24 to L/36
2x10 NLT, 8 1/2” GLT, 7-ply CLT (10” ±) 17’ – 24’approx. L/22 to L/34
designchecks
lateralsystems
strengthshearoverturningcapacity design
(high seismiczones)
serviceabilitystory driftwind-induced
vibrations(tallstructures)
verticalLFRS
wood braced frames
hybrids(steel or concrete LFRS)
P h o to C re dit: E q u ilib riu m C o n su ltin g
decisionsdecisions...
wood, steel, or concrete? walls or frames?
code approvalsbuilding height and lateral load demandsdesigning for resilience?architectural and planning considerations
lateralsystems
connections inhybrids and mass timber?P h o to C re dit: V icB e am
P h o to C re dit: T im b e rP late s.co m
P h o to C re dit: U ih le in -W ilso n A rch ite cts
what’s yourphilosophy?
make itbuildable
make itbeautiful
…and don’t forget aboutmother nature
connections
columnconnection
0
0.5
1
1.5
2
De ad Lo a d E las tic Liv e L oa d E las tic Lo n g itu d ina lS hrin k ag e
C re ep an d Jo in tS ettle m en t
T ot al
Def
lect
ion
(in)
tallwoodhouseat brock commons
wilsonschoolof design
tight-fit pinshear connection a - a
a
a
P h o to C re dit: D G S C o n stru ctio n
inclosing
first principles
it’s notrocket science, but…
you’re not just astructural engineer anymore
thankyou
This concludes the American Institute of Architects Continuing Education Systems Course
Davin Lewis
[email protected] www.fastepp.com