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

Jonathan GoodroadJonathan GoodroadStructural OptionStructural Option2005 Thesis2005 ThesisPenn State AEPenn State AE

Delaware State Delaware State University University

Administration and Administration and Student Services Student Services

BuildingBuilding

DSU Administration BuildingDSU Administration Building

4-Story Office Building4-Story Office Building 88,600 SF88,600 SF Southeast corner of DSU campusSoutheast corner of DSU campus

OutlineOutline Building BackgroundBuilding Background

– GeneralGeneral– ArchitectureArchitecture– Existing StructureExisting Structure

Depth Study – Redesign with Two-way Flat Plate SystemDepth Study – Redesign with Two-way Flat Plate System– Redesign ProposalRedesign Proposal– Gravity SystemGravity System– Lateral SystemLateral System– Building ImpactBuilding Impact– System ComparisonsSystem Comparisons

Breadth Study – Construction Issues Breadth Study – Construction Issues Breadth Study – Mechanical Loading AnalysisBreadth Study – Mechanical Loading Analysis ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions




Breadth Study – Construction IssuesBreadth Study – Construction Issues Breadth Study – Mechanical Loading Analysis Breadth Study – Mechanical Loading Analysis ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions

Building BackgroundBuilding Background

Location: Dover, DelawareLocation: Dover, Delaware Cost: $17.5 millionCost: $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 BackgroundBuilding Background ArchitectureArchitecture

Vertical Circulation

Lounge Area

Offices

Entrance Area

Vertical Circulation


East portion w/ basement + 4 stories East portion w/ basement + 4 stories + mechanical penthouse+ mechanical penthouse

West portion w/ single-story offices West portion w/ single-story offices and 2-story atriumand 2-story atrium


Existing StructureExisting Structure– GravityGravity

Composite steel beam with reinforced concrete slab Composite steel beam with reinforced concrete slab on composite deckon composite deck

3” concrete slab on 2 ½” 20 gage deck3” concrete slab on 2 ½” 20 gage deck Alternating 28’ x21’4” and Alternating 28’ x21’4” and

28’ x22’8” typical bays28’ x22’8” typical bays Typical W16x26 beamsTypical W16x26 beams Typical W24x55 girdersTypical W24x55 girders

Building BackgroundBuilding Background Existing StructureExisting Structure

– LateralLateral Semi-rigid moment connectionsSemi-rigid moment connections Masonry shear walls around elevatorsMasonry shear walls around elevators

Existing StructureExisting Structure – FoundationFoundation

East portion uses 24” mat foundationEast portion uses 24” mat foundation West portion slab on grade with square footings West portion slab on grade with square footings Piers around perimeter of entire footprintPiers around perimeter of entire footprint Grade beam around perimeter of slab on gradeGrade beam around perimeter of slab on grade Wide grade beam down center of matWide grade beam down center of mat





Depth StudyDepth Study

Redesign ProposalRedesign Proposal– Change from steel frame system to cast-Change from steel frame system to cast-

in-place reinforced two-way flat plate in-place reinforced two-way flat plate systemsystem

– Exploration of the concrete design Exploration of the concrete design processprocess

– Compare feasibility differences between Compare feasibility differences between the two systemsthe two systems


Gravity SystemGravity SystemDesign Goals:Design Goals:

Uniform bay sizesUniform bay sizes Consistent column Consistent column

dimensions dimensions – Floor to floorFloor to floor– Across floor planAcross floor plan

Limited effect on Limited effect on architecturearchitecture

– Space dimensionsSpace dimensions– Travel penetrationsTravel penetrations

Design Guides:Design Guides: IBC 2003IBC 2003 ACI 318-02ACI 318-02

Design Analyses:Design Analyses: Equivalent Frame Equivalent Frame

AnalysisAnalysis ADOSSADOSS ETABSETABS


Gravity SystemGravity SystemLoads:Loads:

Floor DeadFloor Dead 20 psf20 psf

Roof DeadRoof Dead 20psf20psf

Exterior WallExterior Wall1.4 klf1.4 klf

Conc. WeightConc. Weight145 pcf145 pcf

Floor LiveFloor Live 100 psf100 psf

Snow LoadSnow Load 20 psf20 psf

Materials:Materials:

4000 psi concrete4000 psi concrete

60000 psi reinforcing60000 psi reinforcing


Gravity SystemGravity SystemDesign:Design:

SlabsSlabs– ADOSS used for designADOSS used for design– 12” flat plate slab12” flat plate slab– #5’s and #7’s#5’s and #7’s


Gravity SystemGravity SystemDesign:Design:ColumnsColumns– ETABS used for load ETABS used for load

determinationdetermination– 22”x 22” columns22”x 22” columns– Most longitudinal reinforcing Most longitudinal reinforcing

controlled by minimum controlled by minimum steel requirementssteel requirements Interior basement level excludedInterior basement level excluded

– Used 4 #10’s in most and 4 #18’s in basement Used 4 #10’s in most and 4 #18’s in basement interior columnsinterior columns


Gravity SystemGravity SystemDesign:Design:

ColumnsColumns

Shear stud strips provide Shear stud strips provide

necessary reinforcement necessary reinforcement

around column areas around column areas

with high shear stress with high shear stress

Max shear stress = 253 psiMax shear stress = 253 psi


Lateral SystemLateral SystemDesign GoalsDesign Goals– Reinforced concrete Reinforced concrete

shear walls used in shear walls used in vertical opening vertical opening locationslocations 2 elevators and 1 2 elevators and 1

mechanical shaftmechanical shaft

– Integrate columns as Integrate columns as

boundary elementsboundary elements

where possiblewhere possible

Design Guides:Design Guides: IBC 2003IBC 2003 ACI 318-02ACI 318-02 ASCE 7-02ASCE 7-02


Lateral SystemLateral System– Wind Load: Wind Load:

Determined from IBC 2003Determined from IBC 2003 Exposure Category C Exposure Category C Basic Wind Speed = Basic Wind Speed = 90 mph90 mph Importance Factor = Importance Factor = 1.15 (Category III)1.15 (Category III) Base Shear =Base Shear = 303 kips303 kips


Lateral SystemLateral System– Seismic Load:Seismic Load:

Determined with IBC 2003 (Chapter 16), ACI Determined with IBC 2003 (Chapter 16), ACI 318-02 (Chapter 21), and ASCE 7-02 318-02 (Chapter 21), and ASCE 7-02

Base Shear = 747 kips


Lateral SystemLateral SystemDesign:Design:

Shear wallsShear walls– Seismic loading governsSeismic loading governs– Stiffness analysis used for Stiffness analysis used for

wall load determinationwall load determination– ETABS used for strength andETABS used for strength and

deflection analysisdeflection analysis



Flexural steel determined with minimum Flexural steel determined with minimum requirementsrequirements

Max steel ratio notedMax steel ratio noted Longitudinal spacing accounted forLongitudinal spacing accounted for Transverse steel spaced at 6”Transverse steel spaced at 6” Shear reinforcement spaced at 6”Shear reinforcement spaced at 6”



Required SteelRequired Steel

(worst case for (worst case for

E-W direction)E-W direction)


Building ImpactBuilding Impact– Building weight greatly increasedBuilding weight greatly increased

Expensive existing foundation may not have Expensive existing foundation may not have capacity to expand on questionable soilcapacity to expand on questionable soil

– Thickness of shear walls may intrude Thickness of shear walls may intrude upon corridor spacesupon corridor spaces

– Floor to floor height reduced by 2’ per Floor to floor height reduced by 2’ per floor, overall building height reducedfloor, overall building height reduced

– Fire rating of 4 hours for concrete, no Fire rating of 4 hours for concrete, no spray on fireproofing requiredspray on fireproofing required


System ComparisonSystem Comparison– Steel system cost approximately $1.5 millionSteel system cost approximately $1.5 million– Concrete system cost approximately $1.9 Concrete system cost approximately $1.9

millionmillion– Concrete requires little lead timeConcrete requires little lead time– Steel construction more preciseSteel construction more precise– Steel system can be fabricated in any Steel system can be fabricated in any

temperaturetemperature Concrete requires warmer temperatures Concrete requires warmer temperatures





Breadth StudyBreadth Study

Construction IssuesConstruction Issues– Concrete constructionConcrete construction

Uniform bays allows for faster floor cycle with consistent Uniform bays allows for faster floor cycle with consistent formworkformwork

– Use of flying forms allows for thisUse of flying forms allows for this Consistent column dimensions add to ease of erectionConsistent column dimensions add to ease of erection

– Rebar changes, dimensions do notRebar changes, dimensions do not Use of #18 bars in basement columnsUse of #18 bars in basement columns

– Requires crane for placementRequires crane for placement Smaller bars may be better choiceSmaller bars may be better choice

Shear stud stripsShear stud strips– Reduces congestion at column locationsReduces congestion at column locations– Provides shear reinforcement without labor of bending barsProvides shear reinforcement without labor of bending bars




Breadth Study – Construction IssuesBreadth Study – Construction Issues Breadth Study – Mechanical Loading AnalysisBreadth Study – Mechanical Loading Analysis ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions


Mechanical Loading AnalysisMechanical Loading Analysis– South facing atrium spaceSouth facing atrium space

Analyze effect of Analyze effect of glazing on cooling glazing on cooling loadload

Using Hourly Using Hourly Analysis Program, Analysis Program, take sample space take sample space and determine and determine effectseffects


Mechanical Loading AnalysisMechanical Loading Analysis– U-value and shading coefficient effect U-value and shading coefficient effect

heat transmission through glazingheat transmission through glazing– U-value is measure of ability to conductU-value is measure of ability to conduct

Lower value = lower heat transmittanceLower value = lower heat transmittance

– Shading coefficient is ratio of heat gain Shading coefficient is ratio of heat gain through selected glazing to heat gain through selected glazing to heat gain through single pane of clear glazingthrough single pane of clear glazing Expressed as <1 Expressed as <1 Lower value = lower heat transmittanceLower value = lower heat transmittance


Mechanical Loading AnalysisMechanical Loading Analysis– Existing glazing: Existing glazing:

U = 0.29U = 0.29 SC = 0.44SC = 0.44

– New glazing:New glazing: U = 0.31U = 0.31 SC = 0.20SC = 0.20


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





ConclusionsConclusions

Concrete design would use 12” slab, Concrete design would use 12” slab, 22” square columns, and 16” 22” square columns, and 16” reinforced concrete shear wallsreinforced concrete shear walls

Steel system more cost effective Steel system more cost effective optionoption

Coordination of trades would require Coordination of trades would require more work for a concrete systemmore work for a concrete system

Better glazing can improve energy Better glazing can improve energy costscosts

AcknowledgementsAcknowledgements

Thanks to…Thanks to…– PSU AE FacultyPSU AE Faculty– Delaware State UniversityDelaware State University– CVM EngineersCVM Engineers– Family and FriendsFamily and Friends– Holly and ToddHolly and Todd

?Questions??Questions?

Documents

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