Timber Frame Design The Art of Engineering an Exposed Structure
Jim DeStefano, P.E. AIA. F.SEI
Disclaimer: This presentation was developed by a third party and is not funded by WoodWorks or the Softwood Lumber Board. “The Wood Products Council” is a This course is registered with AIA CES Registered Provider with The for continuing professional education. American Institute of Architects As such, it does not include content Continuing Education Systems that may be deemed or construed to (AIA/CES), Provider #G516. be an approval or endorsement by the AIA of any material of Credit(s) earned on completion of this construction or any method or course will be reported to AIA CES for manner of handling, using, AIA members. Certificates of distributing, or dealing in any Completion for both AIA members material or product. and non-AIA members are available upon request. ______Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Course Description
Timber engineering is just as much an art as science, one that is rarely taught in college or part of a young engineer’s professional education. With this presentation, attendees have an opportunity to learn from a timber specialist involved in award winning timber-frame projects throughout the northeast. Topics will include the design of heavy timber trusses, glulam elements, joinery and connections, as well as exterior wall systems and designing for fire protection. Learning Objectives
• Apply the principles of timber truss design. • Recognize options for timber-frame exterior wall systems. • Consider basic joinery and connection methods and when to use them. • Determine how to design timber frames for fire resistance. Structural Engineering
The art of molding materials we do not wholly understand into shapes we cannot precisely analyze so as to withstand forces we cannot really assess in such a way that the community at large has no reason to suspect the extent of our ignorance New Canaan Library circa 1977 Saint Joseph Church circa 1987 Saint Patrick Church circa 2007 Hammer Beam Truss Joinery Howe Truss Fink Truss Scissor Truss Hammer Beam Truss Hammer Beam Truss Westminster Hall Cruck Frame The Lodge at Crooked Lake Siren, WI The Depot Kent, CT
3 Simple Rules for engineering of timber joints Rule #1
The geometry of the joint should have mating surfaces that allow all structural loads to be transferred in bearing of one member against the other. Truss Heel Joint Truss King Post Joint Rule #2
The wood removed to create the joint should not unduly weaken the member. Glulam Layup Rule #3
Allow for dimension changes due to seasoning of timber. The geometry of the joint should not be altered by shrinkage of the wood and bearing surfaces should remain in tight contact.
Timber Rivets NDS
• Timber Sizing • Bolted Connections • Timber Rivets www.timberframeengineeringcouncil.org Double Shear in Peg
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Structural Insulated Panels (SIPs) Design Guide for SIPs ww.sips.org Structural Behavior
• Deflections often control • Shear deflection is significant • Shear often controls strength • Creep deflection is significant Fire Resistance of Mass Timber AWC -Technical Report 10 www.awc.org Effective Char Layer Thickness
1 hour 1.8” 1 ½ hour 2.5” 2 hour 3.2” Mass Timber Fire Performance • Collapse proceeded by loud cracking and hissing noise • Collapse proceeded by large deflections • Steel plate and bolt connections fail suddenly Protect Steel Hardware Design for Durability Keep Your Feet Dry 3D BIM QUESTIONS?
This concludes The American Institute of Architects Continuing Education Systems Course
Jim DeStefano, P.E., AIA, F.SEI [email protected]