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Miranova Condominiums Columbus, Ohio Chris Crilly Structural - - PowerPoint PPT Presentation
Miranova Condominiums Columbus, Ohio Chris Crilly Structural - - PowerPoint PPT Presentation
Miranova Condominiums Columbus, Ohio Chris Crilly Structural Option Spring 04 Presentation Outline Project Background Existing Conditions Problem Statement Goals Proposed Solution Floor System Lateral System Other Considerations
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Project Background
Columbus, Ohio Adjacent to I-70 Along Scioto River Faces North into the city Location
N
I-70
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Project Background
Size Gross Building Area Garage - 123,254 SF 5 Stories Tower - 332,862 SF 22 Stories Total - 456,116 SF 27 Stories Cost $52 Million Total Cost Groundbreaking was in July of 1998 Substantial Completion was in October of 2000 Tenant fit out continued into 2002 Construction Dates
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Project Background
Basement Visitor Parking Ground Floor Reception/Lobby Storage Social Spaces Offices Fitness Areas Levels 2-4 Resident Parking Small Storage Spaces Levels 5-28 Condominiums Building Occupancy Approximately 146 High-end Luxury Condominiums Approximately 226 Total parking Spaces
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Project Background
Design Architect – Arquitectonica Architect of Record – HKS Inc. Structural Engineer – The Thornton–Tomasetti Group MEP Engineer – Flack & Kurtz Consulting Engineers Lighting Designer – Lighting Design Alliance Civil Engineer – E M H & T, Inc. Construction Manager – Turner Construction Company Wind Tunnel Consultant – Cermak Peterka Peterson, Inc. Project Team
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Existing Conditions
North Façade – Blue Tinted Glass Curtain Wall Other Façades – 6” Precast Conc. Panels Level 1 – 5 120’ x 250’ Tower 60’ x 280’ 655’ Radius Architecture
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Existing Conditions
Concrete Mat Foundation f’c = 4000 psi – Normal Weight Concrete Placed on a 2” Mud Slab 5’-3” to 5’-9” thick under the tower 2’-9” to 3’-3” thick under 5 story portion Structure – Foundation
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Existing Conditions
8” Post-Tensioned Flat Plate f’c = 5000 psi – Normal Weight Conc. Post Tensioning ½” ∅, 270 ksi Low-Relaxation Strands Banded in 6’ Width over Col. Lines in E/W Direction Uniformly Spaced in N/S Direction Structure – Floor System
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Existing Conditions
Concrete Shear Walls f’c = 5000 psi – Normal Weight Conc. Thickness Decreases up the Building 22” to 12” Thick Structure – Lateral System
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Goals/Criteria
Possibility exists for owner to purchase to adjacent units and connect the two to make a larger living space
Problem Statement
Vertically – due to post-tensioned slabs Very difficult and expensive to execute future expansions: Horizontally – due to R/C shear walls
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Goals/Criteria
Allow greater and cheaper flexibility for possible future renovations
Goals
Vertically Horizontally Minimize impact on architecture Minimize impact on overall cost
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Proposed Solution
Steel Systems More flexible to future changes than concrete Easier to add openings for stairways and ducts Lighter
Floor System
Steel floor systems are typically deeper I will concentrate on Low Floor-to-Floor systems to minimize impact on architecture and cost
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Proposed Solution
Steel Braced Frames More flexible to future changes than concrete shear walls Easier to add openings for doorways Lighter
Lateral System
Braced frames allow for only discrete door locations I will concentrate on maximizing the area for door
- penings for greater future flexibility
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Floor System
Composite Slab and Beam System Slight modification to Beam-Girder connections
- ver typical connections
Reduces floor depth Reduces fabrication time and costs Connection L4x4x12x3” Erection Angle 3 – 1/2” ∅ Erection Bolts
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Floor System
Infill Beams (N-S Span Direction) W10 x 22 – Center Bay W10 x 17 or W10 x 19 – Outer Bays Girders (E-W Span Direction) W12 x 26 to W12 x 40 ∆EL b/w TopBeam and TopGirder 1.625” – 1.875” Allows for 1/8” Mill Tolerance 2” Max Required - 2” – 18 gage VLI Deck
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Floor System
Connection Check Yield Line Analysis Initially Studied by W. S. Easterling of Va. Tech. Followed up with Master’s Thesis by Wey-Jen Lee at Va. Tech
⎥ ⎥ ⎥ ⎥ ⎦ ⎤ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ − + =
g g b f y
b d b b t F R 2 1 4 2 2
2
R = Nominal Strength of Girder Flange Fy = Yield Strength of Girder tf = Thickness of Girder Flange bb = Width of Beam Flange bg = Length of Girder Flange (bf/2 – k1) D = Length of Beam Bearing φ = 0.9 - Assumed
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Floor System
These Capacities are CONSERVATIVE. Why?
Connection Check Connection Check
Beam Web Limit states were also checked and found to be OK Proven by experimental tests Bearing point is assumed to be at Center of Bearing Area Connection similar to un-stiffened seated connection Bearing point determined by beam web limits states simultaneously with bending limit state
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Floor System
Sound & Impact Transmission through floor system Investigated under Acoustic Breadth
Other Design Considerations
Floor Vibrations Typical beams checked Interior Bays Fell in upper half of barely perceptible range of the modified R-M scale
- Max. acceleration – 0.339% < 0.5% OK
Exterior Bays Fell in lower half of slightly perceptible range of the modified R-M scale Max acceleration – 0.495% < 0.5% OK
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Floor System
A typical composite floor system was also designed Typical connections No depth restrictions Partially composite beams Same beam and girder layout was used
Typical Composite System
Infill Beams – W12x19 Girders – W16x26 to W16x30 Beam to Girder Connections – Shear Tab (3) – ¾” ∅ A325 Bolts PL – 3/8” x 4 ½” x 9” A36 5/16” fillet weld φRn = 27.8 k
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Floor System
Cost & Time Advantages Cost & Time Advantages
Shallow System Heavier Members Slightly more shear studs Less Connection Material Less Beam Fabrication (Copes) This was done to compare: Material costs Fabrication costs & Fabrication time
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Lateral System
Combination of R/C shear walls and steel braced frames Steel Braced Frames
Replace large shear walls in N-S Direction 3 options studied to:
- Determine most efficient system
- Determine most economical system
- Maximize available space for future doors
Shear Walls
Keep existing walls around 2 building cores Walls added around building core
- Better protection in emergencies
- Stiffens building
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Lateral System
Option #1: All Braces Option #2: Outer Braces Center Brace – Same as
- ption #1
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Lateral System
Option #3: Eccentrically Braced Frames Pros
4X area for doors in center frame 2X area for doors in outer frames Smaller Columns Acceptable building and story drifts
Design Summary
4 ft link in larger bay
- Ext. Columns – W14x426 to W14x48
- Int. Columns – 2 to 3 sizes smaller
Beams – W16x45 to W18x60 Braces – W12x40 to W12x45
Cons
Slightly larger beams
- Approx. 2X # bracing connections
- Approx. 2X # braces
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Lateral System Final Design
Outer Braces Center Brace
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Lateral System
Comparison b/w Existing and Proposed System
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Lateral System
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Level 5 Diaphragm
Existing Building used Wind Loads from wind tunnel test I used Code stipulated loads which were larger Change in lateral system at level 5 caused large shears in diaphragm Check proved existing diaphragm to be adequate
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Impacts on Arch.
15 ft Building height increase over 20 stories Locations of existing doors in shear walls had to be slightly moved to accommodate the braces, did not greatly impact space layouts 3 additional columns – easily hidden 8” increase in party wall thickness – 4” loss of living space on each side
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Acoustics
Building Code Design Criteria: STC 50 IIC 50 Fire Rating – 2 HR
Floor System
Recommended Design Criteria for Luxury Residences: STC 60 IIC 60
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Acoustics
Properties STC ≅ 62 IIC ≅ 74 – with carpet IIC ≅ 60 – with hard flooring on foam rubber underlay Fire Rating – UL No. D916 – 2 HR rating with 3 ½” slab
- Actual slab is 4 ¼”
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Acoustics
Building Code Design Criteria: STC 50 Fire Rating – 1 HR
Brace Infill Wall
Properties: STC 60 Fire Rating – UL No. U411
- 2 HR
Recommended Design Criteria for Luxury Residences: STC 60
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- Constr. Management
Cost Estimate
Material Labor Equipment Total Floor Slab 1406825 1195081 194338 2796244 Columns 164808 147230 8420 320458 Shear Walls 209181 290109 10497 509787 Totals $1,780,814 $1,632,420 $213,255 $3,626,489
Existing Structure Cost
Material Fabricaction Erection/Labor Total Beams Gravity 328309 131203 114878 574390 Lateral 19723 1291 5253 26267 Braces 23495 2336 6458 32288 Columns Gravity 122870 1538 31102 155510 Lateral 62540 985 15881 79406 Connections 33276 108003 35320 176599 Shear Walls 201814 459507 661321 Floor Slab 926751 252953 1179703 Fire Protection 42251 28743 70994 Totals $1,761,028 $245,357 $950,095 $2,956,480 Square Ft. Cost = 8.88 $/SF
Steel Structure Cost
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- Constr. Management
Cost Estimate
Item Unit Quantity Material Cost Labor Cost Gypsum Board (Cols.) SF 1815 0.42 762 0.34 617 Gypsum Board (Wall) SF 2480 0.42 1042 0.34 843 Glass Fiber Insulation (Ceiling) SF 14661 0.14 2053 0.37 5425 Glass Fiber Insulation (Wall) SF 2480 0.14 347 0.37 918 Precast Curtain Wall SF 348 25.50 8874 5.25 1827 Glass Curtain Wall SF 344 20.00 6880 6.00 2064 Totals/Story $19,958 $11,693 Totals/Building $399,153 $233,869
Additional Costs
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- Constr. Management
Cost Estimate
Totals Structure Savings Total Savings Existing Structure $3,626,489 Steel Redesign $2,956,480 Additional Costs $633,022 $36,988 $670,010
Cost Savings
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- Constr. Management
Site Logistics
Building Offices/Trailers Site Traffic Cranes Steel Shakeout Site Boundary
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Summary/Conclusion
Steel System Concrete System Better Option Total Weight 20% Lighter, Smaller Mat Foundation Possible
- Steel
Ability to Accomadate Renovations Relatively Easy & Inexpensive Difficult & Expensive Steel Cost $37,000 Cheaper
- Steel
Architectural Impacts 15 ft Height Increase, Larger Cladding Cost
- Concrete
Acoustics Better Properties, but More Expensive Meets Criteria Steel Floor Vibrations Meets Criteria Not Typically a Problem in Concrete Concrete Construction Common System w/ Minor Modification Post-Tensioning Requires Skilled Labor Steel Schedule Requires Spray on Fire Proofing Requires Post-Tensioning Equal
System Comparison
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Summary/Conclusion Conclusion Bottom Flange Bearing Beam-to-Girder System With Eccentric Chevron Bracing in larger Bays
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Acknowledgments
AE Faculty
- Dr. Geschwindner – for all of the help and guidance throughout the year
- Dr. Hanagan – for guidance in understanding new connections
Courtney Burroughs – for guidance on acoustical design All other AE faculty – for getting me to the point where I could complete this
Project Team – for allowing me to use the building and providing required materials
- Pizutti Companies
- Robert Sedlak, Flack & Kurtz
- Kirby Chadwell, HKS Inc.
- Leighton Cochran, CPP
- Aine Brazil, The Thornton-Tomasetti Group
Jeremy Smith, Altoona Pipe & Steel Co. – for all the help in estimating steel costs Melissa Toth, P.E. – for all the help, guidance and insight into the AE Thesis Experience My Parents – for guidance, support, and giving my the opportunity to attend PSU and make my dreams come true. Friends & Family – for all the support over the past five years Sarah Steeves – for putting up with me over the past few months while I was constantly busy with thesis
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Questions Miranova Condominiums
Columbus, Ohio Structural Option Spring ‘04 Chris Crilly
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Foundation
3 additional columns added Reduction of 250k to 750k in tower column loads Average of 250k net uplift in braced frame cols. Smaller loads would allow for significantly reduced thickness in mat at most locations Existing mat would require extra tension reinforcement to distribute uplift forces over area in which mat can resist them Wide flange or channel shapes
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- Constr. Management