Jonathan Goodroad Structural Option 2005 Thesis Penn State AE Delaware State University Administration and Student Services Building

DSU Administration Building 4-Story Office Building 4-Story Office Building 88,600 SF 88,600 SF Southeast corner of DSU campus Southeast corner of DSU campus

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Building Background Location: Dover, Delaware Location: Dover, Delaware Cost: $17.5 million Cost: $17.5 million Project Team: Project Team: – –Owner: Delaware State University – –Architect: H2L2 Architects – –Civil Engineer: George, Miles and Buhr, LLP – –Landscape Architect: Synterra – –Structural Engineer: CVM Engineers – –MEP Engineer: Mark Ulrick Engineers – –Construction Manager: EDiS

Building Background Architecture Architecture Vertical Circulation Lounge Area Offices Entrance Area Vertical Circulation

Building Background East portion w/ basement + 4 stories + mechanical penthouse East portion w/ basement + 4 stories + mechanical penthouse West portion w/ single-story offices and 2- story atrium West portion w/ single-story offices and 2- story atrium

Building Background Existing Structure Existing Structure –Gravity  Composite steel beam with reinforced concrete slab on composite deck  3” concrete slab on 2 ½” 20 gage deck  Alternating 28’ x21’4” and 28’ x22’8” typical bays  Typical W16x26 beams  Typical W24x55 girders

Building Background Existing Structure Existing Structure –Lateral  Semi-rigid moment connections  Masonry shear walls around elevators

Existing Structure Existing Structure –Foundation  East portion uses 24” mat foundation  West portion slab on grade with square footings  Piers around perimeter of entire footprint  Grade beam around perimeter of slab on grade  Wide grade beam down center of mat

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Depth Study Redesign Proposal Redesign Proposal –Change from steel frame system to cast-in- place reinforced two-way flat plate system –Exploration of the concrete design process –Compare feasibility differences between the two systems

Depth Study Gravity System Gravity System Design Goals:  Uniform bay sizes  Consistent column dimensions –Floor to floor –Across floor plan  Limited effect on architecture –Space dimensions –Travel penetrations Design Guides:  IBC 2003  ACI Design Analyses:  Equivalent Frame Analysis  ADOSS  ETABS

Depth Study Gravity System Gravity SystemLoads: Floor Dead20 psf Roof Dead20psf Exterior Wall1.4 klf Conc. Weight145 pcf Floor Live100 psf Snow Load20 psf Materials: 4000 psi concrete psi reinforcing

Depth Study Gravity System Gravity SystemDesign:Slabs –ADOSS used for design –12” flat plate slab –#5’s and #7’s

Depth Study Gravity System Gravity SystemDesign:Columns –ETABS used for load determination –22”x 22” columns –Most longitudinal reinforcing controlled by minimum steel requirements  Interior basement level excluded –Used 4 #10’s in most and 4 #18’s in basement interior columns

Depth Study Gravity System Gravity SystemDesign:Columns Shear stud strips provide necessary reinforcement around column areas with high shear stress Max shear stress = 253 psi

Depth Study Lateral System Lateral System Design Goals –Reinforced concrete shear walls used in vertical opening locations  2 elevators and 1 mechanical shaft –Integrate columns as boundary elements where possible Design Guides:  IBC 2003  ACI  ASCE 7-02

Depth Study Lateral System Lateral System –Wind Load:  Determined from IBC 2003  Exposure Category C  Basic Wind Speed = 90 mph  Importance Factor = 1.15 (Category III)  Base Shear =303 kips

Depth Study Lateral System Lateral System –Seismic Load:  Determined with IBC 2003 (Chapter 16), ACI (Chapter 21), and ASCE 7-02 Base Shear = 747 kips

Depth Study Lateral System Lateral SystemDesign: Shear walls –Seismic loading governs –Stiffness analysis used for wall load determination –ETABS used for strength and deflection analysis

Depth Study Lateral System Lateral SystemDesign:  Flexural steel determined with minimum requirements  Max steel ratio noted  Longitudinal spacing accounted for  Transverse steel spaced at 6”  Shear reinforcement spaced at 6”

Depth Study Lateral System Lateral SystemDesign: Required Steel (worst case for E-W direction)

Depth Study Building Impact Building Impact –Building weight greatly increased  Expensive existing foundation may not have capacity to expand on questionable soil –Thickness of shear walls may intrude upon corridor spaces –Floor to floor height reduced by 2’ per floor, overall building height reduced –Fire rating of 4 hours for concrete, no spray on fireproofing required

Depth Study System Comparison System Comparison –Steel system cost approximately $1.5 million –Concrete system cost approximately $1.9 million –Concrete requires little lead time –Steel construction more precise –Steel system can be fabricated in any temperature  Concrete requires warmer temperatures

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Breadth Study Construction Issues Construction Issues –Concrete construction  Uniform bays allows for faster floor cycle with consistent formwork –Use of flying forms allows for this  Consistent column dimensions add to ease of erection –Rebar changes, dimensions do not  Use of #18 bars in basement columns –Requires crane for placement  Smaller bars may be better choice  Shear stud strips –Reduces congestion at column locations –Provides shear reinforcement without labor of bending bars

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Breadth Study Mechanical Loading Analysis Mechanical Loading Analysis –South facing atrium space  Analyze effect of glazing on cooling load  Using Hourly Analysis Program, take sample space and determine effects

Breadth Study Mechanical Loading Analysis Mechanical Loading Analysis –U-value and shading coefficient effect heat transmission through glazing –U-value is measure of ability to conduct  Lower value = lower heat transmittance –Shading coefficient is ratio of heat gain through selected glazing to heat gain through single pane of clear glazing  Expressed as <1  Lower value = lower heat transmittance

Breadth Study Mechanical Loading Analysis Mechanical Loading Analysis –Existing glazing:  U = 0.29  SC = 0.44 –New glazing:  U = 0.31  SC = 0.20

Breadth Study Existing System Cost: $73,500 Existing System Cost: $73,500 Proposed System Cost: $85,000 Proposed System Cost: $85,000 Difference: $11,500 Difference: $11,500 Payback: 4.6 years Payback: 4.6 years

Outline Building Background Building Background –General –Architecture –Existing Structure Depth Study – Redesign with Two-way Flat Plate System Depth Study – Redesign with Two-way Flat Plate System –Redesign Proposal –Gravity System –Lateral System –Building Impact –System Comparisons Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis Conclusions Conclusions Acknowledgements Acknowledgements Questions Questions

Conclusions Concrete design would use 12” slab, 22” square columns, and 16” reinforced concrete shear walls Concrete design would use 12” slab, 22” square columns, and 16” reinforced concrete shear walls Steel system more cost effective option Steel system more cost effective option Coordination of trades would require more work for a concrete system Coordination of trades would require more work for a concrete system Better glazing can improve energy costs Better glazing can improve energy costs

Acknowledgements Thanks to… Thanks to… –PSU AE Faculty –Delaware State University –CVM Engineers –Family and Friends –Holly and Todd

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