All-wood Podiums in Mid-rise Construction
Karyn Beebe, PE, LEED AP
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 of Completion for both AIA members and non-AIA members are available upon request. 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.
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© The Wood Products Council 2012
Learning Objectives
At the end of this program, participants will have:
1. Participants will analyze the code study including the opportunities and challenges for
wood use in this project and be able use that knowledge to specify this type of system
in the future.
2. Attendees will learn the motivational drivers associated with the use of wood for this
project and why they may consider it on future projects vs. typically specified systems
3. Participants will discover the structural challenges associated with a wood podium as
designed in this project and gain a better understanding of the collaboration necessary
with the structural engineer.
4. Participants will understand how the building was designed for durability and longevity
using non-traditional systems and methods.
OUTLINE:
OUTLINE:
Podium Construction Defined
Traditional Podium Construction
Wood Podium Construction
Podium Construction Defined
History Wood Podiums OUTLINE:
Structural Specifications Light-framed shear walls all levels Wood Podium: Engineered Wood System
Wood Structural Panels with gypcrete topping I-joists Glulaminated Beams (Glulams)
Structural Components
Structural Components
Light-framed shear walls Superstructure
Shear wall design methods Architectural Gingerbread
Light-framed shear walls Wood Podium
Focus on Continuity Detailing
Structural Components
Engineered Wood System Wood Structural Panels
Oriented Strand Board (OSB) Plywood for balconies
I-joists and Sawn Lumber
Structural Components Glulam Beams
2 Stress Classes Bending Stress, Modulus of
Elasticity 24F-1.8E (2400 psi, 1.8x106 psi) 30F-2.1E LVL (3000 psi, 2.1x106
psi)
Variety Sizes 5-1/8 inches to 12-1/4 inches wide 10-3/4 inches to 45 inches deep
Structural Components
LVL Laminations
Structural Components
High Strength Composite (HSC) Beams
Hybrid Glulam with LVL Outer Laminations
Full length with no finger joints required
LVL has greater tensile strength compared to lumber
30F-2.1E stress level achieved
Direct substitute for many SCL products
LVL Laminations
Structural Components
Structural Steel Steel Columns & Connections
Price Steel Beams > Glulams
OUTLINE:
Heights and Areas
What factors into determining allowable heights and areas?
Heights and Areas
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Considering a Conventional Code Podium Will the parking work?
509.7 Open parking below Group R Height and area above the open parking garage per section 503; height measured from grade plane including both the garage and the building above the garage. Garage area / height per 406.3
Enclosed Garages: 406.4 Height and area as per table 503 as modified by sections 504, 506, and 507
Type V is OK for S2 Occupancy per table 503
For enclosed garage: Ventilation must be provided per Mechanical Code
Parking Garage is OK in Type VA construction IF it is enclosed
Enclosed Parking Garage
Ventillation Systems required for Enclosed Garages Mech Code: 403.8 Exhaust Ventilation for Enclosed Parking Garages.
Exhaust airflow for enclosed parking garages shall be provided in accordance with the requirements in Table 4-4 and this Section. Exhaust makeup air shall be permitted to be any combination of outdoor air or transfer air.
403.8.2 Alternative Exhaust Ventilation for Enclosed Parking Garages. Mechanical ventilation systems used for enclosed parking garages shall be permitted to operate intermittently where the system is arranged to operate automatically upon detection of vehicle operation or the presence of occupants by approved automatic detection devices.
Part natural and part mechanical ventilation permitted by code Final result: 10,000 cfm system cost 10K
Table 4-4 Parking garages 0.75 cfm / sq ft
Code Area Analysis
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Area AnalysisOccupancy Areas
Level One OccupancyAREAS
Gross SqFt
AREA subtotals
SqFt OLF Net O
r Gro
ss Area adjusted for
Net Occupancy Calculation
Occupant Load A M B S2 R
area subtotal check
Retail/Restaurant/Office Restaurant Seating A2 2209 15 N 2102 140.1 2209 Restaurant kitchen A2 479 200 G 2.4 479 Restaurant service A2 n.o. 496 496 Retail A M 4690 30 G 156.3 4690 Micro Retail B M 461 30 G 15.4 461 Service/Toilets M. 502 30 G 16.7 502 Subtotal 8837 8837
Residential Admin Area Lobby B 971 100 G 9.7 971 Office B 191 100 G 1.9 191 Multipurpose Room A-2 1631 15 N 1536 102.4 1631 Class room A-2 686 20 N 641 32.1 686 Refreshment Center B n.o. 205 200 G 1.0 205 Stair/Elev B n.o. 589 100 G 5.9 589 Service/Hallways/Toilets B n.o. 1042 300 G 3.5 1042 Reception B 204 100 G 2.0 204 Subtotal 5519 5519
Building Foot Print Retail/Resturant/Offfice & Residential Admin Area 14356
Parking Covered S2 22200 200 G 111.0 22200 22200 Open Air S2 2433 Subtotal 24633
Planters & Setbacks 1464
Lot Coverage (openair parking+landscape) 90%
Site Area 40453Total Occupant Load level one all spaces concurrent 600.5Acc: accessory use, not a concurrent occupancyN/O: Not occupied independent of related spaces
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Code Check Resources
Design Challenges & Solutions Durability:
Protected building envelope Different approaches
Oceano Galt
Exposed Conditions
Design Challenges & Solutions
Preservative treatment Naturally durable wood species Alaskan
Yellow Cedar Port Orford
Cedar
Durability:
Top Chord & Webs are DF Bottom Chord AYC
Two accepted fire rating methods recognized in the U.S. IBC Empirical Method NDS Mechanics Based Model
FRT
Design Challenges & Solutions Calculating Fire Resistance of Glulam Beams and
Columns, Technical Note Y245
Design Challenges & Solutions
Horyu-ji temple, Ikaruga, Nara Prefecture, Japan, (c. 711) Urnes stave church , Sogn og Fjordane County, Norway (c. 1150) Government Buildings Historic Reserve in Wellington, NZ (c. 1876)
Design Challenges & Solutions Communication:
Project team Subconsultants Single Engineering Firm
BIM Glulam Manufacturers Emphasis on Stacking
Design Challenges & Solutions Field Modifications:
BIM Hole cutting Field Notching and Drilling of Glulam (APA Form S560)
OUTLINE:
Benefits Enhanced constructability:
Fewer trades on job Less mobilization time Fewer construction delays
Benefits Enhanced constructability:
Improved framing efficiency Large pool experienced and competitive labor Easier field modifications
Benefits Structural:
Decreased mass for lateral design Continuity of lateral system Fewer design team members
Benefits Improved sustainability:
Wood as a building material LEED-HMR Silver (Oceano) LCA
Galt Place is a great example of Smart Growth
Mixed Use Infill and Urban Encourages
transportation choice - car, bus, walk, bicycle
High in Resource Efficiency low energy and land use supports existing
infrastructure Quality Design that
creates a sense of place
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Jb1.wmv
Galt Tracy Sacramento Elk Grove Stockton
Galt Place
Tracy Place Globe Mills
Waterman Square
Hotel Stockton
Loan per Unit $31,250 $88,000 $108,200 $89,000 $61,900
Number of Units 81 50 147 84 156
Total Loan
$2,500,000 $
4,400,000
$15,905,400
$7,476,000 $9,656,400
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Source Amount
Partnership Equity $ 13.4
Mortgage 1st TD $ 3.4 City RDA Loan 2nd TD $ 2.5
Deferred Profit $ 0.8 $ 20.1
Resources APA Case Study, Form No. N110 www.apawood.org www.woodworks.org
Questions?
This concludes The American Institute of Architects Continuing Education Systems Course
Karyn Beebe, PE, LEED AP APA [email protected]