Kingstowne Section 36A Office Building with Parking Garage Fairfax County, VA James Chavanic PSU AE Senior Thesis Structural April 8, 2013 Image Provided By DCS Design Image Provided By DCS Design
P RESENTATION O UTLINE BUILDING INTRODUCTION EXISTING STRUCTURE THESIS PROPOSAL STRUCTURAL DEPTH BREADTH 1: SITE REDESIGN BREADTH 2: FAÇADE REDESIGN (GLAZING) RESULTS QUESTIONS Image Provided By DCS Design Image Provided By DCS Design
P ROJECT I NFORMATION P RESENTATION O UTLINE BUILDING OVERVIEW 200,000 SF 8 Stories (4 Parking, 4 Office) BUILDING INTRODUCTION Height = 101’ - 2” (86’ - 11” from Avg. Grade) $ 19 Million EXISTING STRUCTURE Construction: February 2012 – May 2013 THESIS PROPOSAL STRUCTURAL DEPTH PROJECT TEAM BREADTH 1: SITE REDESIGN Owner: Halle Companies BREADTH 2: FAÇADE REDESIGN (GLAZING) Architect: Davis, Carter, Scott Ltd. (DCS Design) RESULTS GC: L.F. Jennings Inc. QUESTIONS Civil Eng.: Tri-Tek Engineering Mech. Eng.: Jordan & Skala Engineers Struct. Eng.: Cagley & Associates Image From Bing Maps
S ITE R ELATIONSHIP N P RESENTATION O UTLINE BUILDING INTRODUCTION EXISTING STRUCTURE THESIS PROPOSAL STRUCTURAL DEPTH BREADTH 1: SITE REDESIGN BREADTH 2: FAÇADE REDESIGN (GLAZING) RESULTS QUESTIONS 27’ Difference Original Images: DCS Design
E XISTING S TRUCTURE P RESENTATION O UTLINE ROOF 3.25” LW Concrete on 2” 18 GA Composite Deck (Mech. Areas) BUILDING INTRODUCTION 3” x 20 GA Type N Roof Deck (Remaining Areas) EXISTING STRUCTURE THESIS PROPOSAL Spans A- C 45’ - 0” , C - D 36’ - 6” , D - F 43’ - 6” STRUCTURAL DEPTH East West Direction 28’ - 6” BREADTH 1: SITE REDESIGN BREADTH 2: FAÇADE REDESIGN (GLAZING) Composite action in mechanical areas RESULTS (4) 17,000 lb. Roof-top Mechanical Units QUESTIONS Original Image: Cagley & Associates
E XISTING S TRUCTURE P RESENTATION O UTLINE OFFICE LEVELS 2 THROUGH 4 2” x 18 GA Composite Deck 3.25 ” LW Concrete Topping (3000 psi) BUILDING INTRODUCTION Spans EXISTING STRUCTURE A- C 45’ - 0” , C - D 36’ - 6” , D - F 43’ -6 ” East West Direction 28’ - 6” THESIS PROPOSAL Composite action beams and girders STRUCTURAL DEPTH 13’ - 4” Floor to floor height BREADTH 1: SITE REDESIGN BREADTH 2: FAÇADE REDESIGN (GLAZING) Lateral System RESULTS Moment Frames Concentrically Braced Frames QUESTIONS Eccentrically Braced Frames Original Image: Cagley & Associates
E XISTING S TRUCTURE P RESENTATION O UTLINE PARKING LEVELS AND OL1 8” Thick concrete flat slab #4 @ 12” O.C. Bottom Mat BUILDING INTRODUCTION f ’ c = 5000 psi EXISTING STRUCTURE Typical bay is 28’ - 6” x 29’ - 0” 24” x 24” Typical columns THESIS PROPOSAL 10- 8” Floor to floor height STRUCTURAL DEPTH BREADTH 1: SITE REDESIGN Lateral System BREADTH 2: FAÇADE REDESIGN (GLAZING) 12 Shear walls RESULTS 12” Thick f’ c = 5000 psi QUESTIONS #5 @ 12” O.C. Typical E.F. Original Image: Cagley & Associates
E XISTING S TRUCTURE P RESENTATION O UTLINE FOUNDATION All Concrete f’c = 3000 psi 48” Thick concrete mat foundations BUILDING INTRODUCTION Spread Footings EXISTING STRUCTURE 7000 psi bearing capacity 8’ x 8’ to 16’ x 24’ THESIS PROPOSAL STRUCTURAL DEPTH Strip Footings BREADTH 1: SITE REDESIGN 2500 psi bearing capacity BREADTH 2: FAÇADE REDESIGN (GLAZING) RESULTS Geopiers (Rammed Aggregate Piers) 30” Dia. 16’ deep QUESTIONS 100 k capacity each Original Image: Cagley & Associates
P ROPOSED W ORK P RESENTATION O UTLINE SETTING THE STAGE Currently, no tenant selected BUILDING INTRODUCTION Police / Emergency services for Fairfax County, VA EXISTING STRUCTURE www.defense.gov THESIS PROPOSAL Risk Category IV (Originally Category II) STRUCTURAL DEPTH U.S. Department of Defense Standards BREADTH 1: SITE REDESIGN BREADTH 2: FAÇADE REDESIGN (GLAZING) RESULTS QUESTIONS www.asce.org www.gsa.gov
P ROPOSED W ORK BREADTH 1: SITE REDESIGN P RESENTATION O UTLINE Assess potential security issues STRUCTURAL DEPTH Goal Reinforced concrete Reduce risks to human occupants Maintain flat slab system Gravity Design BUILDING INTRODUCTION Use designed OL1 for OL2 - OL4 BREADTH 2: FACADE REDESIGN EXISTING STRUCTURE Design edge beams Design glazing for worst scenario from site redesign THESIS PROPOSAL Design roof structure Goals STRUCTURAL DEPTH Lateral Design Protect occupants of the building Ordinarily reinforced concrete shear walls BREADTH 1: SITE REDESIGN Maintain thermal performance Progressive Collapse Design BREADTH 2: FAÇADE REDESIGN (GLAZING) Satisfy requirements adopted by the U.S. Dept. of Defense RESULTS MAE REQUIREMENTS Goals QUESTIONS AE 530 – Computer Modeling of Building Structures Reduce cost of structural system AE 538 – Earthquake Engineering Simplify construction AE 542 – Building Enclosure Science and Design
G RAVITY D ESIGN DESIGN CONSIDERATIONS P RESENTATION O UTLINE Risk Category IV GRAVITY SYSTEM I snow = 1.2 2 – way flat slab All Concrete f’ c = 5000 psi Office levels BUILDING INTRODUCTION Significantly cheaper than existing steel system Façade Load Reduces floor-to-floor height EXISTING STRUCTURE Assume 100 psf THESIS PROPOSAL Perimeter edge beams STRUCTURAL DEPTH Floor to floor height Creates moment frames BREADTH 1: SITE REDESIGN 9’ - 0” Floor to ceiling Depth constrained to allowed structure plenum 17” Clear space in existing Office structure BREADTH 2: FAÇADE REDESIGN (GLAZING) Provide 24” below flat slab All columns continued from parking levels through office levels RESULTS 8” slab system 2 additional column lines QUESTIONS Result = 11’ - 8” Reduce overall by 7’ - 8” Check strength of existing column designs Higher loads
G RAVITY D ESIGN P RESENTATION O UTLINE DESIGN OF EDGE BEAMS GSA Design Guide Appendix B.3 2(DL + 0.5L) BUILDING INTRODUCTION 9’ - 0” Tributary Width EXISTING STRUCTURE 20” Trial Depth (2.5*h) THESIS PROPOSAL Gives sufficient beam/slab ratio STRUCTURAL DEPTH ACI Moment Coefficients East – West direction BREADTH 1: SITE REDESIGN Frame Analysis BREADTH 2: FAÇADE REDESIGN (GLAZING) North – South direction RESULTS Pattern Loading QUESTIONS
G RAVITY D ESIGN P RESENTATION O UTLINE DESIGN/CHECK OF COLUMNS GSA Design Guide Appendix B.3 2(DL + 0.5L) BUILDING INTRODUCTION Live load reduction considered EXISTING STRUCTURE Spliced at OL1 THESIS PROPOSAL “Check” below STRUCTURAL DEPTH “Design” above Unbalanced moment from slabs BREADTH 1: SITE REDESIGN Spreadsheet BREADTH 2: FAÇADE REDESIGN (GLAZING) Typical columns RESULTS Highest load columns QUESTIONS Typically 129% of Original A s
SOIL LOAD L ATERAL D ESIGN P RESENTATION O UTLINE BUILDING INTRODUCTION EXISTING STRUCTURE THESIS PROPOSAL WIND LOAD SEISMIC LOAD STRUCTURAL DEPTH 120 MPH (Cat. IV) Site Class = D BREADTH 1: SITE REDESIGN Exposure B I seismic = 1.5 BREADTH 2: FAÇADE REDESIGN (GLAZING) GC pi SDC = C Office = 0.18 RESULTS R = 5 (ORC Walls) Parking = 0.55 C s = 0.0249 QUESTIONS Cont. Base Shear Weight = 39,017 k 765 k Base Shear North Blowing 972 k
L ATERAL D ESIGN P RESENTATION O UTLINE ETABS MODEL All elements modeled Idealize parking levels BUILDING INTRODUCTION Total height = 91’ - 4” EXISTING STRUCTURE Effects of cracked sections THESIS PROPOSAL Rigid diaphragms STRUCTURAL DEPTH Columns in-line with walls Walls BREADTH 1: SITE REDESIGN Membrane elements BREADTH 2: FAÇADE REDESIGN (GLAZING) 18” x 18” maximum mesh RESULTS Seismic loads control QUESTIONS Extreme torsional irregularity N-S direction
L ATERAL D ESIGN P RESENTATION O UTLINE SHEAR WALL DESIGN SW7 – SW12 (Same Design) SW7 Worst Case BUILDING INTRODUCTION Seismic N-S Controls EXISTING STRUCTURE Primarily Soil Load THESIS PROPOSAL SW1 – SW3 (Same Design) STRUCTURAL DEPTH SW1 Worst Case Seismic N-S Controls BREADTH 1: SITE REDESIGN SW5, SW6 BREADTH 2: FAÇADE REDESIGN (GLAZING) Not in scope RESULTS SW4 QUESTIONS Architectural interference Seismic E-W Controls
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