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Aspen Art Museum
Creating Innovative Wood Structure
Greg Kingsley, PE, Peng, PhDCEOKL&A Inc., Structural Engineers and Builders
Disclaimer: This presentation was developed by a third party and is not funded by
WoodWorks or the Softwood Lumber Board.
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“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.
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Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
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Course Description
The Aspen Art Museum, designed by architect Shigeru Ban, includes a long-span three-dimensional wood space-frame roof.
Ban’s charge was to create a wood space frame with spans of more than 50 feet and cantilevers of 14 feet, in a structural depth of 3 feet. The space frame was to have two planes of intersecting diagonal webs of curved members that undulated up and down to touch the planes of the top and bottom chords with no visible connectors.
This case study presentation will describe the design and construction of the wood structure, including paths explored but not chosen for the final design.
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Learning Objectives
1. Articulate the particular demands associated with creating a 3-dimensional space frame entirely in wood.
2. Recognize the advantages and disadvantages of several wood connection strategies in space-frame structures.
3. Be aware of manufacturing capabilities and limitations that influenced the design of the Aspen Art Museum roof structure.
4. Understand the importance of early engagement of manufacturing and engineering partners in the design process for innovative wood structures.
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Aspen Art Museum
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Aspen Art Museum
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THE PLAYERS
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OUTLINE
• THE BUILDING CONCEPT
• THE ARCHITECT’S CONCEPT FOR THE ROOF
• 4 STRUCTURAL CONCEPTS FOR THE ROOF
• FABRICATION TESTS: MOCK UPS
• STRENGTH TESTS: MATERIAL TESTING
• FINAL FABRICATION
• ERECTION
• FINISHED BUILDING
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THE BUILDING CONCEPT
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Aspen, Colorado, USA
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Snow load = ~ 90 psf
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Early rendering – view up the main stair
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Early rendering – 3rd floor terrace with wood space frame
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Early rendering – 3rd floor terrace with wood space frame
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BASEMENT GROUND LEVEL
FLOOR PLANS
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2ND FLOOR 3RD FLOOR
FLOOR PLANS
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3RD FLOOR REFLECTED CEILING PLAN
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100 ft x 100 ft on a 4 ft grid Max span = ~ 50ft
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BUILDING SECTION
Maximum 3 ft structural depth
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THE ARCHITECT’S CONCEPT
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STRUCTURAL CONCEPTS
THREE ATTEMPTS AND FAILURES …
AND THE FINAL ROAD TO SUCCESS
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1ST CONCEPT:
REINFORCED LAP SPLICES WITH DEHONIT COMPOSITE MATERIAL
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2ND CONCEPT:
KNIFE PLATES WITH TIGHT DRIVEN PINS
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3RD CONCEPT:
MICRO LAMINATIONS CROSSING AT JOINTS WITH NO HALF LAPS
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Hermann in Paris
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Hermann in Paris
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FINAL CONCEPT:
KERTO CHORDS
BIRCH PLYWOOD WEBS
HALF-LAPPED JOINTS
FULL-THREAD SCREW CONNECTIONS
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KERTO BOTTOM CHORD – LAYER 1
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KERTO BOTTOM CHORD – LAYER 2
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BIRCH PLYWOOD WEB – LAYER 1
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BIRCH PLYWOOD WEB – LAYER 2
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KERTO TOP CHORD – LAYER 1
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KERTO TOP CHORD – LAYER 2
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Connection concept
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4-SCREW
JOINT
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8-SCREW
JOINT
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12-SCREW
JOINT
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15-SCREW
JOINT
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15-SCREW JOINT
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Why Birch?
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WEB LAYOUT
WHY PLYWOOD?
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BIRCH PLYWOOD LAYUP
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1.5 mm
laminations
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BIRCH PLYWOOD WEB SPLICING PATTERN
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TRUSS FABRICATION MODEL OVERVIEW
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STRUCTURAL MODEL
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DEFORMATIONS
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NORMAL FORCES – TOP CHORD
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NORMAL FORCES - WEBS
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NORMAL FORCES – BOTTOM CHORD
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THE MOCK-UP
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TESTING
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BIRCH PLYWOOD LAYUP
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BIRCH PLYWOOD TEST SPECIMENS
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BIRCH PLYWOOD TEST SPECIMENS
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SHOP FABRICATION
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KERTO CHORDS
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BIRCH PLYWOOD LAMINATIONS
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THE “LIBRARY”
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LAYOUT OF BIRCH PLYWOOD IN PREPARATION FOR GLUING
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CLAMPING
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BIRCH PLYWOOD WEB AFTER GLUING
with PURBOND HB E452 single-component polyurethane adhesive
Test
Coupons
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BIRCH PLYWOOD WEB PRODUCTION
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BIRCH PLYWOOD WEBS READY TO SHIP
(NOTE THICKENED WEBS AT COLUMN LOCATION)
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SITE CONSTRUCTION
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TOP OF THE THIRD FLOOR STRUCTURE, READY FOR WOOD
SPACE FRAME INSTALLATION
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SCAFFOLDING
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BOTTOM CHORD
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WEB SPLICES
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COLUMN CONNECTION
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4-SCREW CONNECTION
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8-SCREW CONNECTION
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20,000 SCREWS -7°C (20° F)
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COMPLETED PROJECT
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WHAT WE LEARNED
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The Learning Objectives 1
Articulate the particular demands associated with creating a 3-dimensional space frame entirely in wood.
• Design challenge centers on the nodes and connections.
• Wood is orthotropic: you must orient the wood fibers to your advantage.
• Curved space frame members are beautiful, and yet at odds with their structural function.
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The Learning Objectives 2
Recognize the advantages and disadvantages of several wood connection strategies in space-frame structures.
• Knife plates and bolts are expensive and do not take the best advantage of the wood properties
• Notches in half-lap joints dramatically reduce the strength of wood
• Screws create strong, redundant wood connections
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The Learning Objectives 3
Be aware of manufacturing capabilities and limitations that influenced the design of the Aspen Art Museum roof structure.
• Preparation of precision virtual models is essential.
• CNC fabrication enabled the process
• Engineered wood products were essential
• Hardwood helped
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The Learning Objectives 4
Understand the importance of early engagement of manufacturing and engineering partners in the design process for innovative wood structures.
• I can’t state the answer better than that.
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Questions?
This concludes The American Institute of Architects Continuing Education Systems Course
Greg Kingsley
KL&A Inc., Structural Engineers and Builders
