gsb library atrium analysis knight management building john brooks richard jones reid senescu min...

GSB Library Atrium AnalysisKnight Management Building

John BrooksRichard JonesReid SenescuMin Jae SuhMatt Yamasaki

GSB Library Atrium Building AnalysisKnight Management Center


Options

Base

No Basement Skylights

Alternate

Basement Skylights


Potential Advantages of SkylightPlus Minus

Structure None expected Other beams bigger.Larger lateral deflections.More complex gravity framing

Energy More natural ventilation, less cooling load

Bigger temp. difference between bottom and top of libraryLess insulation, could create more heating/cooling load

Lighting More daylighting, .less energy Potential glare, sunshine on books

Acoustics None expected Louder, more sound absorbing material

CFD Nat. Ventilation better in the summer

Airflow from doors could decrease comfort in winter

Cost Lower life cycle cost Higher first cost, because of less homogenous design

Schedule None expected Added scope, longer duration


Outline

1. Goals and Preferences2. Structure 3. Lighting4. Acoustics5. Cost6. Schedule, 4D7. Energy Analysis8. CFD9. Value Summary10. Decision

For each tool:a) Inputsb) Assumptionsc) Metricsd) Resultse) Confidencef) Comparison


StructureETABS

Revit Structure 2008


Process• Begin with Revit model • Export exr file via CSIxRevit2008• Import files to ETABS• Correct geometry, rebuild moment frame,

establish foundation conditions.• Assign loading conditions• Generate deflection and moment conditions

– Screenshots to PPT

• Evaluate performance (deflections)• Evaluate efficiency (lb of steel/sf)


Assumptions• Default Static Loads

– Dead– Live – Wind

• 3 Types of Quake Analysis– Recreated ARUP user defined loads.– IBC 2006 Defaults.– IBC 2006 matching spectral acceleration to USGS

data.


Baseline Structural System

Y Direction: Braced FrameX Direction: Moment Frame

Baseline Moment Frame


Framing ChangesRevit

Structural framing changes made in Revit to allow for exchange with Building Explorer


MomentsOriginal Atrium

Revised Atrium

Virtually Identical


Deflections


Design Check


Efficiency CheckRevit

Original Structure Revised Structure

Family and Type Count Volume Units Count Volume Units

W16 303 319.11 cf 297 308.53 cf

W18 70 106.61 cf

W21 2 5.24 cf 2 5.24 cf

W24 94 213.41 cf 106 242.28 cf

HSS-BRB 30 37.18 cf 30 37.39 cf

Steel Volume 681.55 cf 593.44 cf

Weight of Steel 306,698 lb 267,048 lb

Building Area 44,220 sf 44,220 sf

Efficiency 6.94 lb/sf 6.04 lb/sf


Structure – MetricsGoal Metric Preference Criteria

-3 0 3

Direct Metrics

Use Materials Responsibly

Weight of Steel 3.4 +10 lb/sf 7 lb/sf

5 lb/sf

Minimize Liability

Deflections 3.0 >5.0 3.0 <1.0

Dependent Metrics

First Cost $


ConfidenceTotal Sub process Effectiveness:• 30% Confident in information transfer:

– Transfer between Revit and ETABS is error prone. • 20% Confident in accuracy of results:

– Worked through several pages of error messages over numerous iterations. Made substantial improvements in consistency of results. Still not completely confident about all inputs.

– Increased efficiency appears to be excessive relative to the framing changes made.

– Getting steel quantities from ETABS would be preferable.


Day LightDaySim


Lighting - Assumptions• Occupied 10 AM to 12 AM• Min. Illuminance: 300 lux• Active and Passive light switching and blind use• Motion and Daylight Sensors• Installed lighting power density 1.5 W/SF


Lighting – MetricsGoal Metric Preference Criteria

-3 0 3

Direct Metrics

Be Beautiful Spatial Quality of Interior Areas

4.0 Claustro-phobic

OK Beautiful

Provide Good Light

Cont. Daylight Autonomy >10%

4.8 0 0 60

Dependent Metrics

Minimize Operation Cost

Energy Cost Per sf / Yr 4.4 2 1.54 1.1

Minimize Net Energy Use

Energy Consumption / Yr 5.6 >2500 2000 1000


20

Skylights provide more light…Annual Light Exposure (lux hours)

Base

No Basement Skylights

Alternate

Basement Skylights


Not much direct light…

Alternate

Basement Skylights

December 21, 2008, 2:00 PM


ConfidenceTotal Sub process Effectiveness:• 100% Confident in information transfer accuracy:

– Performed thorough verification of material transfer– Geometry transferred accurately as .dwg

• 75% Confident in results accuracy:– Architect did not assign materials thoughtfully in Revit– No way of verifying intended material and true material properties– Revit rendering tools (especially animation) seem overly simplistic


Alternate Provides More ValueGoal Metric Base Alternate

Prediction Score Prediction Score

Be Beautiful Spatial Quality of Interior Areas

Dark -2 Nice 1

Provide Good Light DAcon >10% (%) 0 0 24 1

Day Lighting Value -8 8.8


Energy Cost Per Square Foot / Yr

$1049 N/A $968 N/A


Energy Consumption / Yr

7550 kwh N/A 6970 kwh N/A


AcousticsEcotect


26

Information• Goal

What is the acoustic influence of 3 skylights on the 1st floor to the GSB Library?

• ModelsBaseline: Original GSB LibraryAlternate: GSB Library with 3 skylights

• ParameterTwo different volume(Base:11,289m³ vs. Alternate:13,815m³)Two different spots of speaker(Basement vs. 1st Floor)

• Expectative ValueAlternate model produces a longer Reverberation Time in the

two cases because of the bigger volume


Process• Put 3 Skylights to original• Simplify the Revit models with Revit

Architecture 2008• Convert .rvt file to .dxf file• Import .dxf file to ECOTECT 5.5• Design the process with NARRATOR• Refer to the Stakeholder Preference for

MACDAI


28

Assumption• Material Condition (Fixed)


Assumption (Cont)• Sound Condition (Setup 1 speaker)

Baseline Model Alternate Model

1st

Floor

VS.

Basement

VS.


Assumption (Cont)• Sound influences only front half side of the building • Consider only Sabine Algorithm for Reverberation

Time• Consider Audible Speech Frequencies: 500Hz ~ 4KHz (http://squ1.org/wiki/Human_Ear)

• No influence from an outside weather and a noise• 200 Hard-back Chairs, 50% Occupancy


MetricsGoal Metric Preference Criteria

-3 0 3

Direct Metrics

Provide Acoustic

Performance

ReverberationTime (ms)

3.3 Over 7000ms

4000ms~

4999ms

Under 2000m

s

Dependent Metrics


N/A


N/A


Base vs. Alternate• Sound Path (1st Floor)

BaselineAlternate


Base vs. Alternate (Cont)• Sound Path (Basement)

BaselineAlternate


Baseline500Hz~4KHz

Speech Audible Frequency

Base vs. Alternate (Cont)• 1st Floor RT

Alternate500Hz~4KHzSpeech Audible Frequency


Baseline500Hz~4KHz

Speech Audible Frequency

Base vs. Option (Cont)• Basement RT

Alternate500Hz~4KHzSpeech Audible Frequency


Conclusion• Sound Path

Skylights allow the intrusiveness to each floor, but little.

• Reverberation Time Accept Requirement

*Library RT Criteria: Under 2sec (2000ms) (Acoustical considerations in planning and design of library facilities, Denelle&John, Vol 17 No.4, 1999)

All RTs are over the requirement for a library.

Baseline Alternate

1st Floor 2250ms ( )Ⅹ 2525ms ( )Ⅹ

Basement 10040ms ( )Ⅹ 9540ms ( )Ⅹ

Average 6144ms ( )Ⅹ 6034ms ( )Ⅹ


Recommendation• Changing the materials to sound-absorbing materials in the basement for reducing sound reflecting Ex. Acoustical tile ceiling, Carpets,

Fiberglass panels, Fabric wrapped etc.

• Avoiding on parallel walls with sound reflecting surfaces Ex. One wall of the room is glass, the wall opposite should have a sound-absorptive treatment


Confidence• Total Sub process Effectiveness:

100% Confident in information transfer accuracy:– Geometry transferred accurately as .dwg– Performed thorough verification of material transfer

70% Confident in results accuracy:– Architect did not assign materials thoughtfully in Revit– Demolish some structure components in Revit– Material library is short to assign in Ecotect– No way of verifying intended material and true material properties– A noise might replace a speaker as people’s voice– Average reverberation time calculates for the MACDADI result


Baseline & Alternate Same Value

Goal Metric Base Alternate


Provide Acoustic Performance

ReverberationTime (ms)

6000ms~6999ms

-2 6000ms~6999ms

-2

Acoustics Value -6.6 -6.6


Cost and Schedule, 4DBuilding Explorer


Process• Begin with Revitt model • Export database, ifc, scene file

– Assign assemblies to each component in bldngs

• Import files to Building Explorer• Verify Components/Assemblies• Assign geographical location• Produce Schedule• Produce Estimate• Screenshots to PPT…


Assumptions• BE RS Means Database Cost Info Correct

– Had to substitute a few assemblies

• BE Assembly Sequencing Correct– Distributes floor-wise, however structural members

have weird sequencing– Structural, slabs, walls, roof, interior, equipment


Baseline System

Baseline Structural System Baseline Architectural Model -few structural members


Baseline Architectural Costs


Baseline Structural Costs


Baseline Architectural ScheduleArchitectural Model


Baseline Structural Schedule


Baseline 4D Models

Baseline Arch 4D

Baseline Struct 4D


Alternate System

Baseline Structural System Baseline Architectural Model -few structural members


Alternate Architectural Costs


Alternate Structural Costs


Alternate Architectural ScheduleArchitectural Model


Alternate Structural Schedule


Alternate 4D Models

Baseline Arch 4D

Baseline Struct 4D


Summary• Baseline

– Arch Cost: $5,090,875.99– Struct Cost: $181,312.92 – Arch Duration: 308– Struct Duration: 23

• Alternate– Arch Cost: $5,784,021.25– Struct Cost: $216,957.11– Arch Duration: 340– Struct Duration: 28

~10% INCREASE


Metrics

Analysis Goal Metric -3 0 3

Cost/SchedMinimize First Cost $/sqft 195 148 0

Minimize Schedule Duratin days 548 365 0

Base Cost 0Alt Cost 0

Base Sched -1Alt Sched -1

score


Confidence

• Total sub process effectiveness:– 85% confident in information transfer

accuracy• Assembly database missing a few components

– Had to find something comparable

– 95% confident in results accuracy• For what was entered results seemed to be

accurate


Energy and CFDIES


Energy Analysis• Goal:

– To determine operating cost of building– To determine energy consumption of building– To determine environmental impact of building


Energy Analysis• Assumptions:

– Model inputs• HVAC System: Mixed System w/ natural ventilation

– VAV as main system– Natural Ventilation as auxiliary system.

• Weather file: Moffett Field, Mountain View, CA• Building type: Library• Building construction: Educational

– Code regulated floor and roof– Low-e double glazed windows and atrium glass

• Thermal condition: Atrium Each Floor– Fluorescent lighting – 1.5W/SF– People 65 from 10am-12am– Computers – 0.929W/SF– Miscellaneous – 1W/SF– Air exchanges:

» Base case: Natural ventilation – 1 ach, Infiltration: 0.167 ach» Alternative Case: Natural ventilation – 1 ach, infiltration – 0.25 ach

– Simulation• Run period: 1 Jan to 31 Dec• Time step: 10 minutes• Report interval: 60 minutes• Preconditioning: 10 days


Energy Analysis Metrics• Benchmarks (Office building)

– Energy cost: Northern CA average of $1.54– Energy usage: National average of 2000 MMBtu– CO2 emissions: West Coast average of 20lb/sf

Analysis Goal Metric Preference -3 0 3

Energy

Minimize Operation Cost Energy Cost Per sf / Yr 4.4 2 1.54 1.1

Minimize Net Energy Use Energy Consumption / Yr 5.6 >2500 2000 1000

Exhibit Environmental Sustainability Annual CO2 Emissions per sf 4.2 >30 20 0


Energy Analysis Results• Energy consumption:

– Base case: 2402.4MMBtu

– Alternative case: 2470.1MMBtu

Alternative case energy consumption

Base case energy consumption


Energy Analysis Results• CO2 Emissions

– Base Case: 601,404lb/yr– Alternative:– 636,976lb/yr

Base Case CO2 Emissions

Alternative Case CO2 Emissions


Energy Analysis Results• Heating/Cooling Loads

– Base Case:• 276.4MMBtu – heating• 661.5MMBtu – cooling

– Alternative Case:• 188.3MMBtu – heating• 1096.7MMBtu – cooling

Base Case Cooling Loads

Alternative Cooling Loads


Energy Analysis Results• Comparison Charts

Energy Cost

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Jan01-31

Feb01-28

Mar01-31

Apr01-30

May01-31

Jun01-30

Jul01-31

Aug01-31

Sep01-30

Oct01-31

Nov01-30

Dec01-31

Month

Co

st

($)

Base Case

Alternative Case

CO2 Emissions

0

10000

20000

30000

40000

50000

60000

70000

Month

lbC

O2

Base Case

Alternative Case

Total Energy Usage

0

50

100

150

200

250

300

Month

En

erg

y (

MM

Btu

)

Base Case

Alternative Case


Energy Analysis - Confidence• Total sub process effectiveness:

– 90% confident in information transfer accuracy• Geometry transferred accurately• Room data transferred accurately• Unsure about atrium/open spaces

– 60% Confident in results accuracy• Had to build new model from scratch• Inconsistencies in program• Assumptions blackbox


Energy Analysis – Value Comparison

• Base Case provides more value

Goal

Metric

Base Alternative


Minimize Operation Cost Energy Cost Per Square Foot / Yr 2.06 -3.00 2.17 -3.00

Minimize Net Energy Use Energy Consumption / Yr 2402 -1.67 2470 -1.90

Exhibit Environmental Sustainability Annual CO2 Emissions 13.6 1.28 14.4 1.12

Value -17.176 -19.136


CFD Analysis• Goals:

– Determine occupant comfort– Determine thermal condition of room affected by

alteration


CFD Analysis• Process

– Run ApacheSim to get MacroFlo parameters• Problem: Geometry translation• Solution: Necessary output found in ApacheSim


CFD Analysis - Metrics• Benchmark:

– IES<VE> Comfort Indices• 1 – unbearably cold• 7 – perfectly comfortable• 15 – unbearably hot

– Mean percentage of people dissatisfied• Subjective benchmark

– Predicted mean Vote• 0 – neutral• -3 – cold• +3 - hot


CFD Analysis - Metrics• Metrics

Analysis Goal Metric Preference -3 0 3

CFD

Provide Thermal Comfort Percentage of people dissatisfied 3.6 75% 20% 5%

Provide Thermal Comfort Predicted Mean Vote 3.6 3,-3 1,-1 0

Provide Thermal Comfort Comfort Index 3.6 1,13-15 4,10 7


CFD Analysis - Results• Base Case:

– Percentage dissatisfied:• Max: 28%• Min: 5%• Mean: 10%

– Predicted Mean Vote:• Max: 1.04• Min: -0.23• Mean: 0.35

– Comfort Index:• Max: 10• Min: 6• Mean: 8

• Alternative Case:– Percentage dissatisfied:

• Max: 28%• Min: 5%• Mean: 10%

– Predicted Mean Vote• Max: 1.04• Min: -0.23• Mean: 0.38

– Comfort Index:• Max: 10• Min: 6• Mean: 8


CFD Analysis• Graphical

Representation of results

Percentage of dissatisfied occupants

Predicted Mean Vote


CFD Analysis• Stacks study room thermal analysis

– Peak room loads

– Room conditions: Occupied

– Whole day

Room NameTemperature (°F) Relative Humidity (%) PPD (%)

Max Min Max Min Max Min

Base 75 64 70.5 25.7 16.8 5

Alternative 75 64 70.5 25.7 16.6 6

Room Name

Peak Room Conditioning Loads (Btu/h)Internal

*Cooling ChecksGains

Sensible Sensible Humidi- Dehumidi- (Btu/h)(Btu/h·ft²) (cfm/ft²)

Heating Cooling fication fication

Base 24790 26658 3147 8229 35948 5.42 0.35

Alternative 23401 28680 3145 8229 35948 5.83 0.38

Room NameTemperature (°F) Relative Humidity (%) PPD (%)

Max Min Max Min Max Min

18 Room 75 64 76.9 22.2 19.4 5

18 Room 75 64 76.8 22.2 19.3 5


CFD Analysis Confidence• Total sub process effectiveness:

– 0% confident in information transfer accuracy• No errors in geometry transfer• Still finds “external” holes in building even though new

model created– 60% confident in results accuracy

• “Blackbox” effect• Unsure how program treats atrium/open spaces


CFD – Value Comparison• Base case provides more value

Goal

Metric

Base Alternative


Provide Thermal Comfort Percentage of people dissatisfied 10 2.00 10 2.00

Provide Thermal Comfort Predicted Mean Vote 0.35 1.60 0.38 1.48

Provide Thermal Comfort Comfort Index 8 2.00 8 2.00

Value 20.16 19.73


Options are close…..

Base – No Basement Skylights Alternate – Basement Skylights

-0.3 Weighted Value .07 Weighted Value


Include Skylights

Alternate – Basement Skylights

.07 Weighted Value

gsb library atrium analysis knight management building john brooks richard jones reid senescu min...

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