North Shore Equitable Building
Stephan Northrop – Structural Option
Advisor: Dr. Hanagan
April 13, 2011
North Shore Equitable Building
Presentation Outline
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
General Building Information
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
•
Location:
Pittsburgh’s North Shore
•
Owner:
Continental Real-Estate
•
Codes & Loads
•
Occupancy Type:
Low rise commercial
•
Proposed Gravity System
•
Proposed Lateral System
•
Delivery method:
Design build
•
Foundation Assessment
•
Dates of construction: Oct ’03 - Dec ‘04
Acoustic Analysis Breadth
•
Cost:
$70 million
•
Size:
6 stories, 180,000 sq. Ft.
Conclusion
Acknowledgements & Questions
87’1” building height
Stephan Northrop
Structural Option
North Shore Equitable Building
Existing Structural System
Building Introduction
Existing Building Information
Problem Statement
Foundation
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
•
5 ½” Slab on grade
•
18” Auger Cast Piles
•
Steel H piles
•
Light rail transit line accommodation
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Existing Structural System
Building Introduction
Existing Building Information
Problem Statement
Foundation
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
•
5 ½” Slab on grade
•
18” Auger Cast Piles
•
Steel H piles
•
Light rail transit line accommodation
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Existing Structural System
Building Introduction
Existing Building Information
Problem Statement
General Floor Framing
Proposed Solution
Gravity System
Structural Depth
•
5 ½” Lightweight composite floor slab
•
Steel wide flange beams and girders
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W14 steel columns
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Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Lateral System
Acoustic Analysis Breadth
•
N/S Direction: Braced frames
Conclusion
•
E/W Direction: Steel moment frames
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Existing Structural System
Building Introduction
Existing Building Information
Problem Statement
General Floor Framing
Proposed Solution
Gravity System
Structural Depth
•
5 ½” Lightweight composite floor slab
•
Steel wide flange beams and girders
•
W14 steel columns
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Lateral System
Acoustic Analysis Breadth
•
N/S Direction: Braced frames
Conclusion
•
E/W Direction: Steel moment frames
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Problem Statement
Building Introduction
Existing Building Information
Problem Statement
•
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Subgrade light rail transit line poses vibration and
noise control issues
•
Large bay sizes are required
Project Goals
•
Improve noise control
•
Maintain existing grid layout
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Solution
Building Introduction
Existing Building Information
Problem Statement
Structural Depth Study
Proposed Solution
•
Structural Depth
Redesign the structure as a one way concrete pan
joist and beam system
•
Codes & Loads
•
•
Proposed Gravity System
Acoustic Analysis
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
•
Investigate the impact on the building foundation
Investigate the noise reduction benefits of a
concrete structure
Cost & Schedule Analysis (not presented)
•
Investigate the cost and scheduling implications of
a concrete structure
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Solution
Building Introduction
Existing Building Information
Problem Statement
One Way Concrete Pan Joist and Beam System
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
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Inherent noise & vibration reduction
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Ability to accommodate long spans
•
Decreased floor depth
•
Possibility of decreased construction costs
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Codes & Loads
Building Introduction
Existing Building Information
Problem Statement
Existing Design
Proposed Solution
•
100 PSF live loads at all levels
Structural Depth
•
AISC 9th edition, ACI 318-95, and ASCE 7-95 used
•
Codes & Loads
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Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
for design
Redesigned Structure
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80 PSF live load at all upper levels
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100 PSF live load at ground level
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ACI 318-08 and ASCE 7-05 used for redesign
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
Slab/Pan Joist Design
•
Normal weight, 4000 psi concrete
•
Designed using Excel spreadsheets and hand
calculations
•
Codes & Loads
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Proposed Gravity System
•
•
Proposed Lateral System
Slab
•
Foundation Assessment
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24.5” deep floor system
4.5” thick slab with #3 bars @ 12” o.c.
Acoustic Analysis Breadth
Pan Joists
Conclusion
•
20” depth, 7” width
Acknowledgements & Questions
•
Spaced at 60” o.c.
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2 #9 top bars & 2 #10 bottom bars
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Existing Building Information
Problem Statement
Girder Design
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
•
Designed using Excel spreadsheets and hand
calculations
•
24.5” x 40” Girders used for 44’ spans
•
24.5” x 32” girders used for spans less than 44’
Acoustic Analysis Breadth
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Spans > 40’ reinforced with #9 and #10 bars
Conclusion
•
Spans < 40’ reinforced with #8 bars
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Floor System Framing Plan
Existing Building Information
Problem Statement
Floor System Framing Plan
Proposed Solution
•
Decreased tributary area
Structural Depth
•
No additional columns necessary
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Excessive tributary area
Stephan Northrop
Structural Option
Disrupted open floor space
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Existing Building Information
Stairwell & Elevator Shaft Framing
Stairwell & Elevator Shaft Framing
Problem Statement
Proposed Solution
•
Beam widths of 24”, 20” and 16” used
Structural Depth
•
Spans range from 20’ to 44’
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#6 and #8 bars used for reinforcing
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Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Existing Building Information
Column Design
Problem Statement
Proposed Solution
•
Structural Depth
Designed using an Excel spreadsheet and hand
calculations
•
Codes & Loads
•
•
Proposed Gravity System
Exterior Columns
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Checked using spColumn
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24”x48” L-shaped columns at all corners
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24”x48” Rectangular columns along exterior
Interior Columns
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30”x30” and 26”x26” square columns at 1st level
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Sizes decrease with ascending floor level
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Gravity System
Building Introduction
Existing Building Information
Column Design
Problem Statement
Proposed Solution
•
Structural Depth
Designed using an Excel spreadsheet and hand
calculations
•
Codes & Loads
•
•
Proposed Gravity System
Exterior Columns
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Checked using spColumn
•
24”x48” L-shaped columns at all corners
•
24”x48” Rectangular columns along exterior
Interior Columns
•
30”x30” and 26”x26” square columns at 1st level
•
Sizes decrease with ascending floor level
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Problem Statement
•
Ordinary concrete moment frames
Proposed Solution
•
L-shaped and rectangular columns along exterior
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
to add stiffness
•
Concrete shear walls at core avoided to minimize
torsion
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Problem Statement
ETABS Computer Model
Proposed Solution
Modeling Assumptions
Structural Depth
•
Rigid Diaphragms used at all levels
•
Building mass represented as diaphragm
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Codes & Loads
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Proposed Gravity System
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Proposed Lateral System
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Foundation Assessment
Acoustic Analysis Breadth
additional area mass
•
Cracked moment of inertias considered
•
Rigid end offsets applied to all members using a
factor of 0.5
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Problem Statement
Wind & Seismic Loading Application
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Wind Forces
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Calculated using ASCE 7-05 MWFRS
•
North/South direction controls due to a larger
exposure area
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Problem Statement
Wind & Seismic Loading Application
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Seismic Forces
•
Calculated using ASCE 7-05
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Controls over wind due to building weight
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R = 3.0 for ordinary concrete moment frames
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CuTa = 1.76 s (controlling period)
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Problem Statement
Relative Stiffness & Center of Rigidity
Proposed Solution
Structural Depth
•
Stiffness of moment frames range from 65.80
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Codes & Loads
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Proposed Gravity System
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Proposed Lateral System
•
Center of mass at center point of building
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Foundation Assessment
•
Very little eccentricity due to symmetrical design
(K/in) to 170.18 (K/in)
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Proposed Lateral System
Building Introduction
Existing Building Information
Story Deflections
Problem Statement
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Foundation Assessment
Building Introduction
Existing Pile Cap Design
Existing Building Information
Problem Statement
Existing System
Proposed Solution
•
18” Auger cast piles (290 K capacity)
Structural Depth
•
5 piles per typical pile cap
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Bearing capacity = 1450 K per pile cap
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Redesigned System
•
2000.84 K axial load per column
•
7 - 18” piles per pile cap
Acknowledgements & Questions
Stephan Northrop
Structural Option
Redesigned Pile Cap
North Shore Equitable Building
Acoustic Analysis
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Noise Sources under consideration
•
95 dB subway below grade
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71 dB passenger car at parking sublevel
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Mechanical system at roof level
Target dB value at level 1 = 38 dB or less
Acoustic Analysis Breadth
Calculations Performed
Conclusion
•
Transmission Loss through S.O.G. and parking level
Acknowledgements & Questions
•
STL comparison of new and existing roof structures
Stephan Northrop
Structural Option
North Shore Equitable Building
Acoustic Analysis
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
Noise Sources under consideration
•
95 dB subway noise at level 1
•
71 dB passenger car noise at level 1
•
Mechanical noise at roof level
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
Calculations Performed
•
Foundation Assessment
•
STL at parking sublevel
Acoustic Analysis Breadth
•
STL at Level 1
Conclusion
•
STL comparison of new and existing roof structures
Acknowledgements & Questions
Target dB value at level 1 = 38 dB or less
Stephan Northrop
Structural Option
North Shore Equitable Building
Acoustic Analysis
Building Introduction
Existing Building Information
Problem Statement
Conclusions
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
•
Noise transmission is not an issue in the
redesigned system
•
Noise reduction is improved at the roof level
•
Noise reduction is improved in the redesign:
Acoustic Analysis Breadth
•
Increase in slab thickness and density
Conclusion
•
Increase in building weight leads to
decreased vibrations
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Conclusion
Building Introduction
Existing Building Information
Drawbacks to redesigned Structure
All Project Goals were achieved
Problem Statement
Proposed Solution
•
Noise control is improved
Structural Depth
•
Existing grid layout is maintained
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Additional Benefit:
•
Excessively large column and girder sizes
•
Increased building weight
•
Increase construction time
Final Conclusion:
Construction cost is decreased
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
•
Structural Option
•
Costs outweigh benefits
•
Existing structure is the most economical
North Shore Equitable Building
Acknowledgements
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Primary Project Team:
• Mike Hudec
• Robert Modany
• Dina Snider
• Ken Ash
• Louis Mittleman
Continental Real-Estate
Continental Real-Estate
Strada Architects
Michael Baker
Michael Baker
The Pennsylvania State University:
• Dr. Linda Hanagan
• Prof. M Kevin Parfitt
• Prof. Robert Holland
• Ryan Solnosky, Shaun Kreidel and Dr. Andres Lepage
• The entire AE faculty and staff
A special thank you to my friends and family for their constant support
Stephan Northrop
Structural Option
North Shore Equitable Building
Building Introduction
Existing Building Information
Problem Statement
Proposed Solution
Structural Depth
•
Codes & Loads
•
Proposed Gravity System
•
Proposed Lateral System
•
Foundation Assessment
Questions & Comments
Acoustic Analysis Breadth
Conclusion
Acknowledgements & Questions
Stephan Northrop
Structural Option
North Shore Equitable Building
Final Thesis Presentation
Stephan Northrop
Structural Option
North Shore Equitable Building
Additional Information
Stephan Northrop
Structural Option
North Shore Equitable Building
Additional Information
Figure 5-15: East/West Wind Pressure Elevation View
Stephan Northrop
Structural Option
North Shore Equitable Building
Additional Information
E/W wind story forces
Stephan Northrop
N/S wind story forces
Structural Option
North Shore Equitable Building
Additional Information
E/W Seismic story forces
Stephan Northrop
Structural Option