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Discovery Communications

Discovery Communications. Headquarters. Silver Springs, MD. Josh Woolcock Structural Option. Architectural Engineering Pennsylvania State University. Outline. Building Information Existing Conditions Structural Analysis Cost Analysis Schedule Analysis Office Lighting Design

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Discovery Communications

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  1. Discovery Communications Headquarters Silver Springs, MD Josh Woolcock Structural Option Architectural Engineering Pennsylvania State University

  2. Outline • Building Information • Existing Conditions • Structural Analysis • Cost Analysis • Schedule Analysis • Office Lighting Design • Conclusions Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  3. Project Team Owner Discovery Communications Inc. Architect SmithGroup Inc. General Contractor Clark Construction Engineers Structural – KTLH Engineering Civil – VIKA Inc. MEP – Flack & Kurtz Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  4. Building Overview Layout & Function - Multipurpose Office Facility - two independent towers, of 7 and 10-stories - 3 levels of underground parking - 550,000 sqft. of open office space - $52 Million overall cost Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  5. Existing ConditionsMechanical • Individual air-handling units on each floor • Duct work for tenant build-out • - 3 centrifugal water chillers and roof cooling towers • - 3 gas-fired furnaces Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  6. Existing ConditionsLighting / Electrical - Three 4,000A three-phase feeders for three switchboards, totaling 12,000A - Lighting in office space reserved for tenant build-out Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  7. Existing ConditionsStructural • - CIP Concrete Structural System • - Two structurally independent towers • - 2-way cambered 9” structural slab with drop panels • 30’ x 30’ column grid • Column sizes up to 36” x 48” Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  8. Structural Analysis Focus North Tower: 10 Office Floors & Penthouse Purpose To reduce the size of the columns within the office spaces to reduce concrete volume, increase floor space and promote aesthetics. Reasons for Initial Size - Act as both lateral and gravity system - Building sway constraints - Large dead Loads Possible Solutions - Separation of Lateral and Gravity Systems - Reduction of Gravity Loads Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  9. Structural AnalysisInitial Considerations • Loads calculated from IBC2000 • Deflection Requirements • H/400 for service wind loads • H/50 for service seismic loads • Respect to other tower: Contact at 8th Floor • Building Geometry • Much longer than it is wide • -Secondary Considerations • -Building Floor Plan and Impact • Impact on other building systems Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  10. Structural AnalysisFloor Slab Reduction • ADOSS was used: Equivalent Frame Method • Floor slab construction switched from 4000psi to 5000psi concrete • Slab thickness reduced from 9” to 8” • Drop panels remain 7.5” • Slab Reinforcement increased from an average of 4.46psf to 4.89psf • Maximum D+L deflection is 0.759” • Slab weight was reduced by 11% or 11.25kip per column per floor Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  11. Structural AnalysisShear Walls • 4 preliminary locations for shear walls • Locations do no hinder original floor plan • Tests were performed to determine their lateral performance • Use of 4 walls resulted in excess torsion • 2 shear walls were implemented and located to reduce torsion in building Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  12. Structural AnalysisShear Wall Design • Walls Start at floor 1 and continue to main roof • Walls span column-to-column • Design changes at floors 1,3,5 & 7 • Maximum loads – Wind w/ Torsion & Factored • 765.3 kip Shear • 57269.81ft-kip Bending • 1909 kip Axial Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  13. Structural AnalysisShear Wall Design • 24” x 36” columns at ends • Concrete strength • 10000psi at Floor 1 • 8000psi at Floor 3 • 4000psi at floor 5 • Wall Reinforcement • #5@18” Horz. • #5@18” Vert. Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  14. Structural AnalysisShear Transfer • Shear Walls stop at first floor • Columns continue down to foundation • No Bending in Slab • - Shear transferred from walls to floor slab then to retaining walls • - Lateral earth pressure resists shear and locks floor 1 in place Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  15. Structural AnalysisColumn Reduction • All Columns within office spaces are 24” x 24” • 4 different column designs • Concrete Strengths • 8000psi Floor 1 • 6000psi Floor 3 • 4000psi Floor 5 • 4000psi Floor 7 Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  16. Structural AnalysisFinal Lateral System • North-South Direction • Combination of Shear walls and Moment Frames • Contribution via stiffness analysis • 66.8% Shear walls at floor 10 • 90.1% Shear walls at floor 5 • 96.3% Shear walls at Floor 1 • East-West Direction • Moment Frames Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  17. Structural AnalysisLateral System Performance • North-South Direction Notes: Max Wind = 2.66” Max Seismic = 2.54” • East-West Direction Notes: Max Wind = 2.32” Max Seismic = 4.44” Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  18. Structural AnalysisConclusions • Reduction in floor slab produced a 11% decrease in slab dead load on columns • Implementation of Shear Walls reduced bending stresses in columns due to lateral forces • Column size was reduced to 24”x24” throughout the office spaces • - Placement of Shear Walls did not adversely affect building floor plan or mechanical and fire protection services Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  19. Cost AnalysisInitial Considerations Purpose Determine cost implications of new structural systems - Detailed Estimate performed on both original and new structural systems - Costs Estimated using RSMeans 2001 - Bare Costs : Overhead and Profit not included Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  20. Cost AnalysisColumns Notes: - 43.8% Reduction in volume (1210cy) - 25% Reduction in formwork (28000sqft) - 14.3% increase in reinforcement - Cost Savings of $157,017.74 Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  21. Cost AnalysisFloor Slab Notes: - 1” reduction in slab thickness - 11.1% Reduction in volume (1260cy) - 7.2% increase in reinforcement - Increased Cost of $5,493.33 Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  22. Cost AnalysisShear Walls • Notes: • 291.33cy of additional concrete • 14,683.2 sqft of formwork • 12.6 ton of additional reinforcement • Approximately $81,700 in additional cost Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  23. Cost AnalysisConclusions • Notes: • 2178.67 cy reduction in concrete • 14,366 sqft reduction in formwork • 106.66 ton increase in reinforcement • Cost savings of nearly $70,000.00 Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  24. Schedule AnalysisInitial Considerations Purpose Analyze construction time and sequencing of new structural system via floor to floor erection time • Possible construction sequence for the original and new system • Based on a 2 week floor to floor construction time • Production number calculated from 2001 edition of RSMeans • Slab pours would be made every 2 days to facilitate construction of both towers simultaneously Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  25. Schedule AnalysisProduction • Production capacity • 1 crew can erect 3 columns / day • 1 crew can erect 1 shear wall / 2 days Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  26. Schedule AnalysisOriginal System • 70 Columns in 10 days • 2.3 crews needed • Columns • 2 Form crews • 1 Rebar crew • 1 Concrete crew • Elevated Slab • 4 Form Crews • 3 Rebar Crews • 2 Concrete Crews Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  27. Schedule AnalysisNew System • 70 Columns & 2 Shear Walls in 10 days • Equivalent to 82 Columns • 2.73 crews needed • Columns / Shear Wall • 3 Form crews • 1 Rebar crew • 1 Concrete crew • Elevated Slab • 4 Form Crews • 3 Rebar Crews • 2 Concrete Crews Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  28. Schedule AnalysisConclusions • Both systems require same crews for elevated slab work • New structural system requires 1 additional crew for columns / shear walls Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  29. Office LightingInitial Considerations Purpose Design a general lighting system for the open office spaces • Ceiling height is approximately 11’-8” • No finished ceiling • Exposed underside of concrete slab • Exposed Mechanical 18” Deep • Spaces used primarily used for office work • Requires Approximately 50fc or 500lx on the work plane • Best choice for these requirements is an indirect lighting system Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  30. Office LightingDesign • Due to exposed mechanical systems and no finished ceiling, indirect lighting would not work well • Decision to incorporate reflector panels was made • Provide ideal surface for reflected light • Hang 24” from ceiling • Able to provide access to exposed mechanical and fire protection services Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  31. Office LightingResults • Model was created using Lightscape • Peerless LDX030452 was selected • Uses (3) 32W T8 lamps • Input Wattage of 113W • Produced approximately 510lx on work plane • Power density of 0.715 W/sqft Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  32. Office LightingRenderings Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  33. Conclusions & Recommendations • Floor slabs were reduced from 9” to 8” resulting in an 11% reduction in dead load • Implementation of shear walls reduced bending stresses in columns • Column size reduced to 24”x24” • 43.8% reduction in volume • 2200 sqft of additional floor space • New design results in a savings of $70,000 • No change in floor cycle time • Lighting design provides an efficient and aesthetic pleasing system for the general office spaces Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  34. Acknowledgements Thank You to the following…. - Discovery Communications Inc. - Clark Construction Inc. with special consideration to Ray Sowers George Conard Ken Alexander - The entire AE Faculty with special consideration to Dr. Lewis Geschwindner Dr. Thomas Boothby Dr. Linda Hanagan - My Family - My Friends in and out of Architectural Engineering Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  35. Questions Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  36. Location • Silver Springs, MD • Intersections of Georgia Avenue and Colesville Road • Approximately 8 miles from downtown Washington D.C. Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  37. Building Overview Layout & Function - Multipurpose Office Facility - two independent towers, of 7 and 10-stories - 3 levels of underground parking - 550,000 sqft. of open office space - $52 Million overall cost Architecture - Aluminum and Glass curtain wall system -12-story glass atrium connects the two building - Rooftop Terrace and Garden Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  38. Structural AnalysisShear Walls • No impact on existing mechanical and Fire Protection Services Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  39. Structural Analysis3D Analysis Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

  40. Breadth Aspects Lateral System Cost Analysis Determine cost implications of new structural systems Lateral System Schedule Analysis Analyze construction time and sequencing of new structural system via floor to floor erection time Office Lighting Design Design a general lighting system for the open office spaces Pennsylvania State University Architectural Engineering Josh Woolcock Structural Option

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