Miranova Condominiums Columbus Ohio Chris Crilly Structural Option

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 Acoustics Construction Management Summary/Conclusions Acknowledgments Questions

Project Background Location N Columbus, Ohio Adjacent to I-70 Along Scioto River Faces North into the city I-70

Project Background Construction Dates Groundbreaking was in July of 1998 Substantial Completion was in October of 2000 Tenant fit out continued into 2002 Size Gross Building Area Garage - 123, 254 SF Tower - 332, 862 SF Total - 456, 116 SF Cost $52 Million Total Cost 5 Stories 22 Stories 27 Stories

Project Background Building Occupancy 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 Approximately 146 High-end Luxury Condominiums Approximately 226 Total parking Spaces

Project Background Project Team 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.

Existing Conditions Architecture 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

Existing Conditions Structure – Foundation 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

Existing Conditions Structure – Floor System 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

Existing Conditions Structure – Lateral System Concrete Shear Walls f’c = 5000 psi – Normal Weight Conc. Thickness Decreases up the Building 22” to 12” Thick

Goals/Criteria Problem Statement Possibility exists for owner to purchase to adjacent units and connect the two to make a larger living space Very difficult and expensive to execute future expansions: Vertically – due to post-tensioned slabs Horizontally – due to R/C shear walls

Goals/Criteria Goals Allow greater and cheaper flexibility for possible future renovations Vertically Horizontally Minimize impact on overall cost Minimize impact on architecture

Proposed Solution Floor System Steel Systems More flexible to future changes than concrete Easier to add openings for stairways and ducts Lighter Steel floor systems are typically deeper I will concentrate on Low Floor-to-Floor systems to minimize impact on architecture and cost

Proposed Solution Lateral System Steel Braced Frames More flexible to future changes than concrete shear walls Easier to add openings for doorways Lighter 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 L 4 x 4 x 12 x 3” Erection Angle 3 – 1/2” Erection Bolts

Floor System Infill Beams (N-S Span Direction) W 10 x 22 – Center Bay W 10 x 17 or W 10 x 19 – Outer Bays Girders (E-W Span Direction) W 12 x 26 to W 12 x 40 ΔEL b/w Top. Beam and Top. Girder 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 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 – k 1) D = Length of Beam Bearing φ = 0. 9 - Assumed

Floor System Connection Check These Capacities are CONSERVATIVE. Why? 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 Beam Web Limit states were also checked and found to be OK

Floor System Other Design Considerations Sound & Impact Transmission through floor system Investigated under Acoustic Breadth 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 Typical Composite System A typical composite floor system was also designed Typical connections No depth restrictions Partially composite beams Same beam and girder layout was used Infill Beams – W 12 x 19 Girders – W 16 x 26 to W 16 x 30 Beam to Girder Connections – Shear Tab (3) – ¾” A 325 Bolts PL – 3/8” x 4 ½” x 9” A 36 5/16” fillet weld φRn = 27. 8 k

Floor System Cost & Time Advantages This was done to compare: Material costs Fabrication costs & Fabrication time Shallow System Heavier Members Slightly more shear studs Less Connection Material Less Beam Fabrication (Copes)

Lateral System Combination of R/C shear walls and steel braced frames Shear Walls Keep existing walls around 2 building cores Walls added around building core • Better protection in emergencies • Stiffens building 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

Lateral System Option #1: All Braces Option #2: Outer Braces Center Brace – Same as option #1

Lateral System Option #3: Eccentrically Braced Frames Design Summary 4 ft link in larger bay Ext. Columns – W 14 x 426 to W 14 x 48 Int. Columns – 2 to 3 sizes smaller Beams – W 16 x 45 to W 18 x 60 Braces – W 12 x 40 to W 12 x 45 Pros 4 X area for doors in center frame 2 X area for doors in outer frames Smaller Columns Acceptable building and story drifts Cons Slightly larger beams Approx. 2 X # bracing connections Approx. 2 X # 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 Floor System Building Code Design Criteria: STC 50 IIC 50 Fire Rating – 2 HR 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. D 916 – 2 HR rating with 3 ½” slab • Actual slab is 4 ¼”

Acoustics Brace Infill Wall Building Code Design Criteria: STC 50 Fire Rating – 1 HR Recommended Design Criteria for Luxury Residences: STC 60 Properties: STC 60 Fire Rating – UL No. U 411 • 2 HR

Constr. Management Cost Estimate

Constr. Management Cost Estimate

Constr. Management Cost Estimate

Constr. Management Site Logistics

Summary/Conclusion System Comparison

Summary/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

Miranova Condominiums Columbus, Ohio Questions Chris Crilly Structural Option Spring ‘ 04

Foundation 3 additional columns added Reduction of 250 k to 750 k in tower column loads Average of 250 k 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