Techniques for Successful Timber Office Design: Versatility and Performance
Melissa Kroskey, AIA, SE Technical Director, WoodWorks “The Wood Products Council” is a This course is registered with AIA Registered Provider with The CES for continuing professional American Institute of Architects education. As such, it does not Continuing Education Systems include content that may be deemed (AIA/CES), Provider #G516. or construed to be an approval or endorsement by the AIA of any Credit(s) earned on completion of this material of construction or any course will be reported to AIA CES for method or manner of handling, AIA members. Certificates of using, 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
A new trend in office construction finds major developers investing in timber designs. Learn how wood construction can accommodate the space and performance needs of office occupancies, while providing advantages such as speed, cost savings, and reduced environmental impact. This presentation answers the “how” questions of design, examining the potential for both light- frame and heavy timber structural solutions. Topics include fire and life safety design, cost-effective structural layout, acoustics, and aesthetics. Learning Objectives
1. Review building code opportunities related to fire and life safety, with emphasis on construction types, fire resistance, and interior/exterior finish requirements. 2. Explore a variety of suitable structural layouts for light-frame wood solutions, demonstrating how to achieve flexibility of space and function. 3. Explore a variety of suitable structural layouts for heavy timber solutions, demonstrating how to achieve flexibility of space and function. 4. Discover how to address design considerations such as acoustics and aesthetics. OUTLINE
• Market Analysis • Fire Resistance: Construction Types, Sprinklers & Exposing Wood • Healthy Office Buildings • Understanding Cost & Value • Class A Heavy/ Mass Timber Offices • Class B/C Light-Frame Wood Offices • Grids & Structural Solutions Suburban Low-rise Office David & Lucile Packard Foundation
VB • 2 story
• 49,000 sf
• Custom irregular footprint
Jeremy Bittermann, courtesy EHDD
Location: Los Altos, CA Architect: EHDD Engineer: Tipping Mar Urban Speculative Mid-rise Office Wythe Ave Buildings
IV (HT) • (1) 5 Story Bldg (1) 3 Story Bldg • 360 Wythe: 83,000 sf office, retail & apartments • 320 Wythe: 17,000 sf office & retail • Urban infill • Flexible, open office Photo: Flank Architecture + Development
Location: New York, NY Architect: Flank Architecture + Development Engineer: Tharpe Engineering Construction Types: Table 601
2015 IBC $$$ Decreasing Cost $
IA IB IIA IIB IIIA IIIB IV VA VB (HT)
Protected/ Less Protected/ Unprotected P LP P U P LP LP P U
Cost Source: ICC Building Valuation Data, Aug 2018 Type I: Highrise Type III: Mass Timber Type IV: Mass Timber Type V: Mass Timber
Type II: Steel Frame Type III: Tilt-Up Type IV: Heavy Timber Type V: Light Frame Construction Types (2015 IBC Chapter 6)
$$$ Decreasing Cost $ Type I Type II Type III Type IV Type V IA IB IIA IIB IIIA IIIB IV (HT) VA VB Non-combustible Non-combustible Non-combustible Non-combustible Exterior, Roof & Materials & Structure Exterior & Exterior: Exterior: Interior Elements Components FRT wood allowed FRT wood allowed Any material Roof Covered CLT allowed allowed by code FRT wood allowed* Roof Roof & Interior Wood Frame, Heavy Timber & Elements: Interior Heavy Timber Heavy Timber, Roof (Type IB) FRT wood allowed Any material framing, floors & roof Mass Timber Heavy Timber allowed by code all allowed allowed Nonbearing walls Wood Frame, FRT wood allowed** Heavy Timber, Nonbearing walls Mass Timber FRT wood allowed** all allowed
* Type IA buildings > 2 stories above grade, FRT wood NOT permitted in roof where floor to roof distance less than 20 ft
** Type I & II buildings: Interior non-bearing partitions allow FRT wood where FRR is 2 hours or less; exterior non-bearing walls allow FRT wood where no FRR is required. Heights & Areas: 3 to 4 Stories
Multi-story Business Occupancy (B) 3-4 Stories, 60-75 ft Tall IBC 2015/ 2018 Tables 504.3, 504.4, 506.2 (wood shear walls limited to 65’ w/ allowable increases in SDC D, E & F)
Heights & Areas IIB IIIB VA VB
Stories1 4 4 4 3 Height1 (ft) 75 75 70 60 Max Story Area2 (ft2) 69 k 57 k 54 k 27 k Total Bldg Area3 (ft2) 207 k 171 k 162 k 81 k
Assumptions: IIB IIIB 1 VB NFPA 13 sprinkler increase (IBC 504.2) 24% 2 NFPA 13 sprinkler increase (IBC 506.3) VA 81,000 sf more 3 Stories 3 or more (IBC 506.4) 162,000 sf Heights & Areas: 5 to 6 Stories
Multi-story Business Occupancy (B) 6 Stories, 85-ft Tall IBC 2015/ 2018 Tables 504.3, 504.4, 506.2 (wood shear walls limited to 65’ in SDC D, E & F) w/ allowable increases
Heights & Areas IIA IIIA IV (HT) Stories1 6 6 6 Height1 (ft) 85 85 85 Max Story Area2 (ft2) 112 k 85 k 108 k Total Bldg Area3 (ft2) 337 k 256 k 324 k
IIA IV Assumptions: IIIA 1 NFPA 13 sprinkler increase (IBC 504.2) 4% 27% 256,000 sf 2 NFPA 13 sprinkler increase (IBC 506.3) more more 3 Stories 3 or more (IBC 506.4) Heights & Areas
Multi-story, Business Occupancy (B) IBC 2015 Table 503 w/ allowable increases
3 to 4 Stories 5 to 6 Stories Steel/ Wood Steel/ Wood Conc Conc Heights & Areas IIB IIIB VA VB IIA IIIA IV (HT) Stories1 4 4 4 3 6 6 6 Height1 (ft) 75 75 70 60 85 85 85 Max Story Area2(ft2) 69 k 57 k 54 k 27 k 112 k 85 k 108 k Total Bldg Area3 (ft2) 207 k 171 k 162 k 81 k 337 k 256 k 324 k Assumptions: 1 NFPA 13 sprinkler increase (IBC 504.2) 2 NFPA 13 sprinkler increase (IBC 506.3) 3 Stories 3 or more (IBC 506.4) $
Achieving high performance expectations … affordably Market Analysis
Legend: 1600 Wood 1400 Wood is Conc/ Steel 1200
under utilized (Qty (Qty in2017) in office construction 1000 75% office bldgs 800 < 50,000 sf 600 …think wood
400 Office Projects Projects Office
200
0 50 100 150 200 250 300 350 400 450 >450 Project Size (sf x 1000) Market Analysis 2000 Legend: Wood is 1800 1600 Wood under utilized 1500 90% office bldgs Conc/ Steel in office construction. 1400 < 4 stories 1300 Most office projects …think wood could be wood 1200 1000 construction. 800
600
400 Office & Bank Projects BankProjects & Office (Qty (Qty 2017) in 200
1 – 4 stories 5 – 6 stories 7 + stories Height Office Construction Costs
(B) Business Occupancy 250
200 “..where wood frame construction is allowed, 150 depending on location and occupancy, this would help 100 to keep costs lower. In areas Cost / sf / Cost that are restricted to non- 50 flammable construction, price per square foot will go up.” 0 IA IB IIA IIB IIIA IIIB IV VA VB -EV Studio Article (full service Design firm)
Source: ICC Building Valuation Data, Aug 2018 https://cdn-web.iccsafe.org/wp-content/uploads/BVD-BSJ-AUG18.output.pdf 1 to 4 Story Office Construction Cost (Built National Average)
Built light-frame wood Legend: office buildings Wood (light-frame) 20 – 30% less expensive Concrete/ Steel than non-wood office bldgs. The misconception that wood buildings are smaller likely contributes to this statistic.
$196 Avg The industry is not utilizing $133 Avg wood to it’s full capacity in heights & areas
…how much could a 2011
light-frame wood building 2011
2013 2015 2009 2009 2010 2012 2014 2015 2016 2017 2009 2010 2012 2013 2014 2016 2017 save you? Office & Bank Buildings (1 to 4 Stories) Source: Dodge Analytics Data Mass Timber Design & Cost Optimization Checklists
• Aid in design & cost optimization of Checklists: mass timber projects ✓ Pre-Design • Guiding discussions between: ❑ • Designers (architects & engineers) ❑✓ SD Design Optimization • Builders (general contractors, estimators, fabricators & installers) ❑✓ SD Cost Optimization • Owners (developers & construction ❑✓ DD Design Optimization managers) ❑✓ DD Cost Optimization Download Mass Timber Design & Cost Optimization Checklists at WoodWorks.org (coming out soon in 2019) Fire resistance ratings: construction type impacts Type III Construction
Exterior walls • noncombustible materials • Fire Retardant Treated (FRT) wood permitted where fire rating 2hr or less Roof & Interior construction • wood or any material permissible by code Partitions • wood or any material permissible by code Mass Timber: Higher Leasing Rates Clay Creative
IIIA ❑ • 5 Story Type IIIA over 1 story Type IA deck ❑ • 72,000 sf ❑ • Existing brick shell w/ new ❑ heavy timber interior • NLT floors w/ WSP & 1.5” gyp ❑ Glulam beams & columns • Getting $7/SF more Photos: Christian Columbres annually than non-timber office Location: Portland, OR buildings in the area1 Architect: Mackenzie Engineer: Kramer Gehlen & Associates Type IV Construction (2015 & 2018 IBC)
Exterior walls • noncombustible materials • Fire Retardant Treated (FRT) wood & covered CLT permitted where fire rating 2hr or less Roof & Interior construction • solid or laminated wood • Prescriptive minimum sizes • no concealed spaces Partitions • solid wood OR of 1hr fire-resistance Type IV Construction (2015 & 2018 IBC)
• Prescriptive minimum sizes (IBC 602.4) • CLT (added in the 2015 IBC) 3” min thick @ roof 4” min thick @ floor • CLT in exterior walls protect w/ FRT sheathing, ½” gypsum, or other non-combustible materials • 2021 IBC code will expand Type IV to a handful of sub-types (allowing for mass timber buildings up to 18 stories) T3 Minneapolis Michael Green Architecture | Photo: Ema Peter No Concealed Spaces: Type IV Construction (2015 & 2018 IBC) Industrial Aesthetics & Amenities to Attract Top Talent T3 Minneapolis
IV (HT)
• 6 Story Type IV over 1 story podium • 220,000 sf
• NLT floors Glulam beams & columns
Photo: Structurecraft
Location: Minneapolis, MN Architect: MGA | Michael Green Architecture, DLR Group Engineer: Magnusson Klemencic Associates Design Assist + Build Type V Construction
Exterior walls, Roof & Interior construction • wood or any material permissible by code Partitions • wood or any material permissible by code Architect/ Developer Office: Sustainable & Industrial Green Office Building
VB • 2 story
• 15,200 sf
• Exposed wood roof trusses & decking • Mixed-use office w/ light industrial space • Natural ventilation &
Photo: Billy Hustace Photography maximized daylight w/ narrow building wings Location: Berkeley, CA Architect: Marcy Wong Donn Logan Architects Engineer: Gregory P. Luth Associates Fire-Resistive Construction (TBL 601 & 602 w/ B occupancy)
Legend:
2 - hr
1 – hr
0 - hr
Primary Structural Frame: 1-hr @ Type IIA & IIIA Shaft Walls: 2-hr when > 4 stories
1-hr when < 4 stories bearing wall bearing bearing wall bearing (IBC 2015 707.3.1 & 713.4) FSD FSD IIA Ext Walls: bearing 1-hr 2-hr bearing IIIA FSD > 30’ & non-brg 0-hr 1-hr non-brg 0-hr non-brg & FSD > 30’ Fire-Resistive Construction (TBL 601 & 602 w/ B occupancy)
Legend: hr hr
- 2 - hr
interior interior partitions wood solid 1 or 1 – hr
(HT)
0 - hr
Primary Structural Frame: 1-hr @ Type IIA HT @ Type IV
Shaft Walls: bearing wall bearing bearing wall bearing 2-hr when > 4 stories FSD FSD 1-hr when < 4 stories IIA Ext Walls: bearing 1-hr 2-hr bearing IV (HT) FSD > 30’ & non-brg 0-hr 1-hr non-brg (IBC 2015 707.3.1 & 713.4) 0-hr non-brg & FSD > 30’ Fire-Resistive Construction (TBL 601 & 602 w/ B occupancy)
Legend: 2 - hr
1 - hr
0 - hr
Primary Structural Frame: 0-hr @ Type IIB & IIIB
Shaft Walls: 2-hr when > 4 stories
1-hr when < 4 stories
bearing wall bearing wall bearing (IBC 2015 707.3.1 & 713.4) FSD FSD IIB Ext Walls: 1-hr 2-hr bearing IIIB FSD > 10’ 0-hr 1-hr non-brg 0-hr non-brg & FSD > 30’ Fire-Resistive Construction (TBL 601 & 602 w/ B occupancy)
Legend: 2 - hr
1 - hr
0 - hr
Primary Structural Frame: 1-hr @ Type VA 0-hr @ Type VB
Shaft Walls:
2-hr when > 4 stories bearing wall bearing bearing wall bearing 1-hr when < 4 stories FSD FSD (IBC 2015 707.3.1 & 713.4) VA Ext Walls: bearing 1-hr 1-hr VB FSD > 30’ & non-brg 0-hr 0-hr FSD > 10’ Fire Wall – Separate Buildings/ Increase Area (IBC 706)
• Separate buildings for Building 1 Building 2 allowable area & construction type requirements • Stability of fire wall: must be maintained to allow collapse & stability on opposite sides of wall (ex: cantilevered wall, laterally supported & tied walls, double wall) • Noncombustible materials Legend – Fire Wall for B Occupancy (See 706.4 for other occ.): except Type V 3 - hr for Type I, III & IV 2 - hr for Type II & V Sprinklers in Floor Cavities: NFPA 13 Standard
• Floor cavities require sprinklers when: • NFPA 13 sprinklers are required for Height & Area increases or as a substitute for fire rating (only under 2012 IBC) • Cavity does not contain fire stops partitioning space to a volume of 160 ft3 or less • 1” max furred ceiling and batt insulation provided at bottom flange • Fire stop is equal to material used in joist web • Sprinkler heads in floor cavities may increase cost of NFPA 13 sprinkler system
8.15.1.2.6 Concealed spaces formed by ceilings attached 8.15.1.2.8 Concealed spaces within wood joist to composite wood joist construction either directly or onto construction and composite wood joist construction metal channels not exceeding 1 in. (25 mm) in depth, having noncombustible insulation filling the space from provided the joist channels are firestopped into volumes the ceiling up to the bottom edge of the joist of the roof or each not exceeding 160 ft^3 (4.5 m^3) using materials floor deck, provided that in composite wood joist equivalent to the web construction and at least 3-1/2 in. (90 construction the joist channels separated into volumes mm) of batt insulation is installed at the bottom of the joist each not exceeding 160 ft^3 (4.5 m^3) to the full depth of channels when the ceiling is attached utilizing metal the composite wood joist with material equivalent to the channels, shall not require sprinkler protection. web construction, shall not require sprinkler protection. Sprinklers in Floor Cavities – How might this change design?
IIIA VA IIIB IV (HT) VB
Stories 5 3 3 5 2 Height (ft) 65 50 55 65 40 Max Story Area (ft2) 28 k 18 k 19 k 36 k 9 k
3 2 No Sprinklers No Total Bldg Area (ft ) 85 k 54 k 57 k 108 k 27 k Concealed Spaces Opportunity to Expose Sprinklers & Framing IIIA VA IIIB IV (HT) VB
Stories 6 4 4 6 3 Height (ft) 85 70 75 85 60 Max Story Area (ft2) 85 k 57 k 108 k 54 k 27 k 3 Assumes 3 or more w/ Sprinklers w/ Total Bldg Area3 (ft2) 256 k 162 k 171 k 324 k 81 k stories (IBC 506.4) Exposing wood framing: Code paths to warm aesthetic value Exposing Framing: Mass Timber (Type IIIB & IV)
• Mass Timber typ intent is to expose wood structure • For Type IV, exposure is permitted by providing min prescriptive sizes Legend: • For Type IIIB, there is an 2 – hr advantage of not being 1 - hr restricted by concealed 0 - hr spaces See Fire Resistive
Construction slides bearing wall bearing for detailed information • Where rating required, can FSD Primary Structural Frame: provide calcs for char IIIB 2-hr bearing 0-hr @ Type IIIB 1-hr non-brg resistance (incl. exterior & 0-hr non-brg & FSD > 30’ shaft walls) Radiating Industrial Vibes & Energy Efficiency The Radiator
IIIB
• 5 story
• 36,000 sf
• Industrial aesthetic
• Glulam beams & columns Timber decking Light-framed shearwalls
Photo: Josh Partee & Caitlin Murray
Location: Portland, OR Architect: PATH Architecture Engineer: Munzing Structural Engineering Exposing Framing: Mass Timber (Type IIIA)
• Type IIIA allows for up to 6 stories, similar to Type IV • Some projects opt for Type IIIA over IV to allow for concealed space to run Legend: electrical & data 2 – hr • Type IIIA requires more 1 - hr ratings than IIIB, so to 0 - hr expose framing, need to See Fire Resistive Construction slides
bearing wall bearing demonstrate fire resistance for detailed information FSD through char calcs or Primary Structural Frame: IIIA 2-hr bearing 1-hr @ Type IIIA tested assemblies 1-hr non-brg 0-hr non-brg & x > 30’ Mass Timber: Higher Leasing Rates Clay Creative
IIIA
• Office w/ amenities & retail • 90,000 sf • Exposed: • Glulam beams & columns • NLT floor deck • Raised floor system for MEP & acoustics • Leasing for $7/sf more Photos: Christian Columbres annually than non-timber office Location: Portland, OR buildings in the area1 Architect: Mackenzie Engineer: Kramer Gehlen & Associates Exposing Framing: Light Frame (Type VA & VB)
• Exposing framing is easy where no fire rating required • Where rating is required Legend: can provide char calcs 2 – hr • For light-frame elements, 1 - hr may need to provide some 0 - hr residual load capacity of See Fire Resistive Construction slides the member.
for detailed information bearing wall bearing
FSD Primary Structural Frame: VA Ext Walls: bearing 1-hr 1-hr @ Type VA FSD > 30’ & non-brg 0-hr 0-hr @ Type VB Exposed Trusses: Open Office Space Washington Fruit & Produce Company
VB • 16,500 sf
• Trusses span 50’ over open office • Angled glulam columns
• Wood SIPS roof panels
• Light-framed walls
• Reclaimed wood Photos: Kevin Scott
Location: Yakima, WA Architect: Graham Baba Architects Engineer: M.A. Wright, LLC Exposing Framing: Fire Resistance
visit www.woodworks.org/ask-an-expert Exposing Framing: Interior Finishes
Wood Interior Finish (IBC 803.11) • Building occupancy • Location of the material in building • Sprinklers/ no sprinklers
Flame Spread & Smoke Development Index • ASTM E84 or UL 723 Test Method Photo: Benny Chan TBWA/ Chiat/ Day Offices Class Flame Spread Smoke Development Location: San Francisco, CA Index* Index Architect: Marmol Radziner & Associates Engineer: Tipping Mar and Associates A 0 - 25 0 - 450 B 30 - 75 0 - 450 AWC’s DCA 1 lists FlamePhotos: Spread Kevin Scott C 80 - 200 0 - 450 and Smoke Developed Indices for several softwood species *DCA 1 explains that flame spread values are rounded to the nearest multiple of 5 **www.awc.org/pdf/codes-standards/publications/dca/AWC-DCA1-FlameSpreadPerformance-1706.pdf Exposing Framing: Interior Finishes
Interior Finish Requirements Finish Class Wall & Ceiling B Occupancy (IBC Table 803.11) Sprinklered Non- Sprinklered Interior exit stairways, ramps and exit B A passageways 1 Corridors & enclosure for exit access C B stairways & ramps Photo: Josh Partee Rooms & enclosed spaces C C Radiator Location: Portland, OR 1 Architect: Path Architecture Interior exit stairways and ramps in buildings < 3 stories above grade: Engineer: Munzing Structural Engineering Class B finish for non-sprinklered buildings & Class C finish for sprinklered buildings
Heavy Timber Exemption (803.3) Exposed portions of structural members complying w/ Type IV requirements exempt from interior finish requirements MEP: Exposed Mass Timber Buildings
visit www.woodworks.org/ask-an-expert Wood in the Facade Exterior Finishes: Wall Coverings (IBC 1406)
Combustible exterior wall coverings Type I, II, III & IV construction: • Limited to 40 feet above grade plane • Where fire separation is < 5 ft max 10% of exterior wall surface • FRT materials: no limit in surface area where fire separation is < 5 ft permitted up to 60 feet above grade
Type V construction: Photo: Patrick Coulie GSA Office Building No limitations on wood finishes Location: Albuquerque, NM Architect: Page Southerland Page, LLP Engineer: Walter P. Moore & Associates Note: Exterior weather exposure requires additional specification to address UV and moisture. Exterior Finishes: Wood Veneers (IBC 1405.5)
Type I, II, III & IV construction • Min thickness: 1” (nominal) solid veneer 0.438” exterior hardboard 0.375” wood structural panel • Max height above grade: 40 ft (60 ft if FRT) One North • Noncombustible backing required Architect: Holst Architecture | Photo: Andrew Pogue FRT framing in Types III & IV construction may comply • Max projection 24” from building
Wood & wood-based products exempt from NFPA 268 testing for ignition resistance. Note: Exterior weather exposure requires additional specification to address UV and moisture. Radiator Architect: PATH Architecture | Photo: Josh Partree & Catlin Murray Exterior Walls: Fire Resistance
Fire-resistance rating is greater of: Legend: • Tables 601 & 602 Exterior rating Interior rating Fire exposure on interior only or both sides? (705.5): • FSD < 10 ft, rated for exposure to fire from both sides • FSD > 10 feet, rated for exposure to fire from the inside Example: Type IIIB or Type IV Bldg • Non-Bearing @ 20 ft 1hr rated from inside • Non-Bearing @ 5 ft 1hr rated from both sides FSD The Value Proposition Heavy/ Mass Timber
Great solutions for:
• Market Distinction
• Larger Scale
• Open Layout
• Urban Infill
Industrial aesthetic many cities are running out of cool old warehouses to renovate
Photo: Marcus Kauffman, ODF Energy efficient Class A Office One North
IIIB • 5 Story Type IIIB & separate 4 Story Type VA • Value: rental rates surpass downtown Portland…but it's not in downtown!1 • Class A office space in an area that doesn’t usually have class A offices • Wood helps moderate humidity (in concert w/ dense- packed cellulose insulation) Photo: Andrew Pogue • 50% more efficient than typical Location: Portland, OR 3 Architect: Holst Architecture new building in Oregon Engineer: Froelich Engineers Leading Developer Embraces Mass Timber Offices T3 = Timber, Transit & Technology
IV (HT)
• 6 stories Type IV over podium • 220,000 sf • Hines – leading developer embraces innovation & sustainability • NLT floors, glulam frame • Timber erection: 2.5 months total
Photos: Ema Peter; MGA 9 days per 30,000-sf floor • Founation savings: Location: Minneapolis, MN Architect: Michael Green Architecture, DLR Group 30% lighter than steel Engineer: Magnusson Klemencic Associates 60% lighter than conc Hines’ Mass Timber Offices Rising in Southeast T3 West Midtown, Atlanta
IV (HT) • 6 stories Type IV over podium • 205,000 sf • 85-ft tall • DLT floors, glulam frame • T3 Atlanta replaces concrete with steel braced- frame lateral system to keep up with fast speed of mass timber erection
Location: Atlanta, GA Architect: Hartshorne Plunkard Architects + DLR Group Engineer: Magnusson Klemencic Associates Mass Timber: Higher Leasing Rates Clay Creative
IIIA
• 5 Story Type IIIA over 1 story Type IA deck • Net cost: $300 - $350/sf of rentable space1 • Flexible, open office • 80’ x 200’ footprint • 30’x30’ bays @ center • 25’x30’ bays @ perimeter Photos: Christian Columbres • Leasing for $7/sf more Location: Portland, OR annually than non-timber office Architect: Mackenzie 1 Engineer: Kramer Gehlen & Associates buildings in the area Time Savings = $$ Savings for the Bank First Tech Credit Union
IIIA • 5 Story • 156,000 sf (Largest CLT & glulam building in the US) • Lighter wood $$ savings eliminated deep foundations & costly ground improvements6 • 15-week (Total Construction) 12-week (Timber erection) 6 • Up to 5% Savings (Swinerton) 6 Photos: StructurLam w/ Mass Timber • Prefabricated & precise: Location: Hillsboro, OR Architect: Hacker 4,200 MEP penetrations Engineer: Kramer Gehlen & Associates CNC shop fabricated First Brick & Beam Buildings in NY in Nearly a Century Wythe Ave Buildings
IV (HT) • NLT black Spruce from sustainably managed forest • Glulam beams & columns • Leasing sooner than originally forecast, potential added revenue of $800k4 • Estimated savings
Photo: Flank Architecture + Development $1.3 to 1.7 MM over a comparable concrete Location: New York, NY Architect: Flank Architecture + Development office building4 Engineer: Tharpe Engineering Mass Timber Structure - Value
Tangible Value: Intangible Value:
Lightweight structure Biophilia Lower involuntary Reduced costs (cranes, stress environment foundations, etc.)
Schedule build faster Unique Aesthetic Occupy sooner Market Distinction
Prefabrication Reduced Carbon Footprint Less on-site labor
Fewer finishes Lower Environmental Reduced cost, schedule & Impacts environmental impact Other Intangibles: • Offices have high risk & large stock - hard to make $$ • Mass timber provides market distinction • Workplace aesthetics high priority for millennials • Mass timber provides aesthetically pleasing space for talent attraction/ retention Light Frame Wood Office
Great solutions for:
• Low-rise (1-4 stories)
• Custom
• Irregular in footprint
Green Office Building Wong Logan Architects | Photo: Billy Hustace Medical Offices within Budget: Lighter Wood Building Bonner General Health
VB • 3 Story • 50,000 sf • 32’ floor spans; large spaces for future flexibility • Vibration critical • 28” deep I-joists w/ lightweight conc topping & gypsum ceiling to further Photos: xxx dampen vibrations Location: Sandpoint, ID Architect: John Eixenberger Engineer: Hoit Engineering Medical Offices within Budget: Lighter Wood Building Bonner General Health
VB • Originally steel frame design • Poor soils needed lighter structure • Light wood framing reduced costs; savings in foundations1
“Not only did wood give us a more economical structure, but we could more easily source our labor needs with wood Photos: RedBuilt framing, too.”
Location: Sandpoint, ID Architect: John Eixenberger -Construction Manager Engineer: Hoit Engineering Jim Williamson 3
2
1
T M B R
Can wood accommodate the grid spacing needed for adaptable office floor plans? Typical Lateral Systems
Light Frame Diaphragms & Shearwalls: • Lateral Core Resisting System: • Typical for 1 to 5 stories • Typical for buildings > 3 stories • Need ample wall at perimeter • Allows for maxium exterior glazing • Typically assume flexible diaphragm • May use rigid or semi-rigid analysis • Compatible w/ custom/ private offices (semi-rigid if used with frames at exterior) • Ideal for speculative/ open offices Interior Shearwalls w/ Exterior Glazing Exterior Barrier Wall w/ Internal Insulation
Interior Moment Frame w/ Exterior Wood Walls Exterior Steel Moment Frame w/ Core Flexibility Open Office: Building Layout Example Urban, Regular Footprint, Speculative
Courtesy of Arch Nexus Open Office: Building Layout
25,000 sf Floor Plate 40’ Centralized core is fixed 110’ 30’
40’
30’ 100’ 30’ Open office to 60’ to 60’ Core (30’x100’) 210’ Open Office: Building Layout
Clear span from exterior to core for 40’ maximum flexibility
Common span for steel 30’ grid ~ 40 ft
40’
24’ Open office to 30’ Core (30’x100’) (typ) Office Floor Framing: Rectangular Grid
X Member Sizes (approx.) Office Floor Framing
X Joist Depth Y Glulam Girder Size
38-46” 24’ 8 ¾”x33” 24F-V4 40’ Pinned or Plated Truss 30’ 10 ¾”x 39” 24F-V4
Assumptions: • DL = 30 psf & LL = 65 psf Y Note: All member sizing needs to be confirmed by a licensed engineer for specific conditions of your project. • Steel Structure Rule of Thumb ~ 1”/depth per 1’/span • Adapting from a square to rectangular grid, depth of system can be matched Semi-Open Office: Building Layout
Bearing/ shear walls 5-ply CLT Structural Deck 5 ply CLT @ roof 7 ply CLT @ floors Beams (glulams) 8 ¾"x27" @ roof 10 ½"x40 ½“ @ floors (exterior bays) 10 ½"x31 ½“ @ floors (interior bays) Girders 10 ½"x43 ½“ @ floors Columns 8 ½"x9" to 10 ½“ sq Semi-Open Office: Building Layout
12’-15’ Likely some private offices (assume at perimeter) 25’-28’
30’
25’-28’
12’-15’ Open office 30’ Private office typ (12’x10’ to 12’x20’) Core (30’x100’) 210’ Semi-Open Office: Building Layout
12’-15’ Ancillary spaces work well near central core 25’-28’ For increased daylight penetration, can flip & 30’ locate private offices near core 25’-28’
12’-15’ Open office 30’ Private office typ (12’x10’ to 12’x20’) Core (30’x100’) Office Floor Framing: Joist Layout
Member Sizes (approx.) Office Floor Framing Y X X Joist Depth Y Glulam Girder Size
3-1/8”x22 ½” 24F-V4 28-30” I-Joist 12’ or or 5-1/8”x18” 24F-V4 30’ 24-34” Pinned or 8 ¾”x 34 ½” 24F-V4 Plated Truss 28’ Or 10 ¾”x31 ½” 24F-V4
Assumptions: • DL = 30 psf & LL = 65 psf Note: All member sizing needs to be confirmed by a licensed engineer for specific conditions of your project. Office Floor Framing: Purlin & Girder Layout
Member Sizes (approx.) Office Floor Framing Glulam Girder X 2x Sub-Purlin Purlin @ 8’ oc Y 8’ Bay Spacing Size X 5-1/8”x18” 6-3/4”x25 ½” 22’ 2x8 @ 16” 24F-V4 24F-V4 5-1/8”x19 ½” 6-3/4”x28 ½” 24’ 2x8 @ 16” 24F-V4 24F-V4 5-1/8”x22 ½” 8-3/4”x33” 28’ 2x8 @ 16” 24F-V4 24F-V4 Assumptions: • DL = 30 psf & LL = 65 psf Note: All member sizing needs to be confirmed by a licensed engineer for specific conditions of your project. Office Floor Framing: Solid Wood Layout
Member Sizes (approx.) Office Floor Framing Mass Timber Glulam X X Glulam Girder X Panel Purlin 2x8 NLT or 5-1/8”x24” 20’ None 7-PLY CLT 24F-V4 6-3/4”x30” or 2x6 NLT or 5-1/8”x24” 25’ 8-3/4”x27” 5-PLY CLT @ 12.5’ oc 24F-V4 5-1/8”x28- 8-3/4”x36” or 2x6 NLT or 30’ 1/2” 10-3/4”x33” 3-PLY CLT @ 10’ oc 24F-V4
Assumptions: • DL = 30 psf & LL = 65 psf Note: All member sizing needs to be confirmed by a licensed engineer for specific conditions of your project. Irregular Plan Example: Custom Suburban Office Building Irregular Plan Example: Building Layout 2 Stories 16,000 sf / floor
Open office
Private office (10’x12’)
Corridor (5’ wide) Stairs/ elevators Irregular Plan Example: Building Layout 22’ typ
30’ typ
12’
22’ x 30’ grid easily done w/ wood 12’ 22’ 22’ Office Floor Framing: Joist and Beam Layout
Member Sizes (approx.) Office Floor Framing Y X X Joist Depth Y Glulam Girder Size
16” I-Joist or 6 ¾“x34 ½“ or 22’ 30’ 18” Plated 8 ¾”x31 ½” 24F-V4 Truss 28-30” I-Joist or 6 ¾“x30“ or 30’ 24-34” Pinned 22’ 8 ¾”x27” 24F-V4 or Plated Truss Assumptions: • DL = 30 psf & LL = 65 psf Note: All member sizing needs to be confirmed by a licensed engineer for specific conditions of your project. Floor Assembly
4’ Deep Wood Assembly: • 1 ½” gypsum over ¾” sheathing • 24” wood trusses • 27” glulam beam • 15.75” drop ceiling
4’ Deep Steel Assembly: • 4” concrete slab deck • 18” bar Joists • 24” Beam • 17.5” Drop Ceiling Office Design Resource
www.woodworks.org/wp-content/uploads/case_study-Wood-Offices.pdf Questions? This concludes The American Institute of Architects Continuing Education Systems Course
Melissa Kroskey, AIA, SE Technical Director - WoodWorks (858)527-9340 [email protected] Copyright Materials
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