miranova condominiums
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Miranova CondominiumsColumbus, Ohio
Structural Option Spring ‘04Chris Crilly
Presentation Outline
Goals
Floor System
Lateral System
Acoustics
Construction Management
Acknowledgments
Questions
Existing Conditions
Project Background
Proposed Solution
Other Considerations
Summary/Conclusions
Problem Statement
Project Background
Columbus, Ohio
Adjacent to I-70
Along Scioto River
Faces North into the city
Location
N
I-70
Project Background
Size
Gross Building AreaGarage - 123,254 SF 5 Stories Tower - 332,862 SF 22 StoriesTotal - 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
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
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
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
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
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
Existing Conditions
Concrete Shear Walls
f’c = 5000 psi – Normal Weight Conc.
Thickness Decreases up the Building
22” to 12” Thick
Structure – Lateral System
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
Goals/Criteria
Allow greater and cheaper flexibility for possible future renovations
Goals
Vertically
Horizontally
Minimize impact on architecture
Minimize impact on overall cost
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
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 openings for greater future flexibility
Floor System
Composite Slab and Beam System
Slight modification to Beam-Girder connections over typical connections
Reduces floor depth Reduces fabrication time and costs
Connection
L4x4x12x3” Erection Angle
3 – 1/2” Erection Bolts
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
ΔEL b/w TopBeam and TopGirder
1.625” – 1.875” Allows for 1/8” Mill Tolerance 2” Max Required - 2” – 18 gage VLI Deck
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
fy
bd
bb
tFR
21
42
2
2
R = Nominal Strength of Girder FlangeFy = Yield Strength of Girdertf = Thickness of Girder Flangebb = Width of Beam Flangebg = Length of Girder Flange (bf/2 – k1)D = Length of Beam Bearingφ = 0.9 - Assumed
Floor System
These Capacities are CONSERVATIVE. Why?
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
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
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
Floor System
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
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
Lateral System
Option #1: All Braces Option #2: Outer Braces Center Brace – Same as
option #1
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
Lateral System
Final Design
Outer Braces Center Brace
Lateral System
Comparison b/w Existing and Proposed System
Lateral System
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
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
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
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”
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
Constr. Management
Cost Estimate
Material Labor Equipment TotalFloor Slab 1406825 1195081 194338 2796244Columns 164808 147230 8420 320458
Shear Walls 209181 290109 10497 509787Totals $1,780,814 $1,632,420 $213,255 $3,626,489
Existing Structure CostMaterial Labor Equipment Total
Floor Slab 1406825 1195081 194338 2796244Columns 164808 147230 8420 320458
Shear Walls 209181 290109 10497 509787Totals $1,780,814 $1,632,420 $213,255 $3,626,489
Existing Structure Cost
Material Fabricaction Erection/Labor TotalBeams
Gravity 328309 131203 114878 574390Lateral 19723 1291 5253 26267
Braces 23495 2336 6458 32288Columns
Gravity 122870 1538 31102 155510Lateral 62540 985 15881 79406
Connections 33276 108003 35320 176599Shear Walls 201814 0 459507 661321Floor Slab 926751 0 252953 1179703Fire Protection 42251 0 28743 70994Totals $1,761,028 $245,357 $950,095 $2,956,480
Square Ft. Cost = 8.88 $/SF
Steel Structure CostMaterial Fabricaction Erection/Labor Total
BeamsGravity 328309 131203 114878 574390Lateral 19723 1291 5253 26267
Braces 23495 2336 6458 32288Columns
Gravity 122870 1538 31102 155510Lateral 62540 985 15881 79406
Connections 33276 108003 35320 176599Shear Walls 201814 0 459507 661321Floor Slab 926751 0 252953 1179703Fire Protection 42251 0 28743 70994Totals $1,761,028 $245,357 $950,095 $2,956,480
Square Ft. Cost = 8.88 $/SF
Steel Structure Cost
Constr. Management
Cost Estimate
Item Unit Quantity Material Cost Labor CostGypsum Board (Cols.) SF 1815 0.42 762 0.34 617Gypsum 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 1827Glass Curtain Wall SF 344 20.00 6880 6.00 2064
Totals/Story $19,958 $11,693Totals/Building $399,153 $233,869
Additional CostsItem Unit Quantity Material Cost Labor Cost
Gypsum Board (Cols.) SF 1815 0.42 762 0.34 617Gypsum 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 1827Glass Curtain Wall SF 344 20.00 6880 6.00 2064
Totals/Story $19,958 $11,693Totals/Building $399,153 $233,869
Additional Costs
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 SavingsTotals Structure Savings Total Savings
Existing Structure $3,626,489
Steel Redesign $2,956,480
Additional Costs $633,022
$36,988$670,010
Cost Savings
Constr. Management
Site Logistics
Building
Offices/Trailers
Site Traffic
Cranes
Steel Shakeout
Site Boundary
Summary/Conclusion
Steel System Concrete System Better Option
Total Weight20% Lighter, Smaller Mat
Foundation Possible--- Steel
Ability to Accomadate Renovations
Relatively Easy & Inexpensive
Difficult & Expensive Steel
Cost $37,000 Cheaper --- Steel
Architectural Impacts15 ft Height Increase, Larger Cladding Cost
--- Concrete
AcousticsBetter Properties, but
More ExpensiveMeets Criteria Steel
Floor Vibrations Meets CriteriaNot Typically a Problem in
Concrete Concrete
ConstructionCommon System w/ Minor
ModificationPost-Tensioning Requires
Skilled LaborSteel
ScheduleRequires Spray on Fire
ProofingRequires Post-Tensioning Equal
Steel System Concrete System Better Option
Total Weight20% Lighter, Smaller Mat
Foundation Possible--- Steel
Ability to Accomadate Renovations
Relatively Easy & Inexpensive
Difficult & Expensive Steel
Cost $37,000 Cheaper --- Steel
Architectural Impacts15 ft Height Increase, Larger Cladding Cost
--- Concrete
AcousticsBetter Properties, but
More ExpensiveMeets Criteria Steel
Floor Vibrations Meets CriteriaNot Typically a Problem in
Concrete Concrete
ConstructionCommon System w/ Minor
ModificationPost-Tensioning Requires
Skilled LaborSteel
ScheduleRequires Spray on Fire
ProofingRequires Post-Tensioning Equal
System Comparison
Summary/Conclusion
Conclusion
Bottom Flange Bearing Beam-to-Girder System With Eccentric Chevron Bracing in larger Bays
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
Questions
Miranova CondominiumsColumbus, Ohio
Structural Option Spring ‘04Chris Crilly
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
Constr. Management
Other Issues
Steel Lead Time Excavation and construction of foundation & first five stories will
provide sufficient time for steel to be on sight Required lead time will not delay schedule
Schedule Impact Only rough calculations performed Steel structure can be erected faster than existing concrete
structure Additional gypsum board, glass fiber insulation, and curtain
wall will add time to schedule Overall schedule construction duration not effected
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