GSB Library Atrium Analysis

John BrooksRichard JonesReid SenescuMin Jae SuhMatt Yamasaki

Options

Base

No Basement Skylights

Alternate

Basement Skylights

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, less 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

Outline1. Structure 2. Lighting3. Acoustics4. Schedule, 4D5. Cost6. Energy Analysis7. CFD8. Sample Money Slide9. Challenges and Resolutions

For each tool:a) Assumptionsb) Metricsc) Results

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Static Load Conditions• Dead Load• Live Load• Earthquake

IBC 2006: Inputs are fixed.

• WindASCE 7-02 Wind LoadingApplied to all area objectsWind speed = 100 mphUnknown Inputs: importance factor, exposure type,

topographical factor, gust factor, directionality factor

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Model Analysis• Analysis Goal

Determine maximum moments & deflections under given loading conditions

Determine demand capacity ratios for all members

• Analysis ParameterDimensions of membersJoints: ReleasesMaterialsLoads: Load combinations

8

Revit Structure• Regenerate Revit Architecture model

9

ETABS

• Import Revit model• Correct geometric errors• Define “dummy surfaces”• Define additional load parameters &

combinations• Analyze

10

Analysis Result

• ETABS generates shear, moment, deflection and demand capacity data on structure.

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Earthquake Displacements

• Displacements in original design due to earthquake are excessive.

• Possibly due to invalid inputs.

12

Design Check

• Numerous failures of structural members in original design.

• Possibly due to invalid inputs.

Lighting - Occupant Behavior

• Occupied 8 AM to 5 PM• Min. Illuminance: 500 lux• Active and Passive light switching and blind use• Manual on/off switch near door• Installed lighting power density 1.5 W/SF

Lighting – Analysis Assumptions

• Time Step: 30 minutes• Ground Reflectance: 0.2

Lighting – MetricsUnits Measurement -3 0 3

Daylighting Aesthetics

unitless My opinion Claustro-phobic

ok beautiful

Lighting Cost

Dollars / SF

Energy $3410 $1746 $737

Lighting Quality

% of sensors

Continuous Daylight Factor > 40%

0% 40% 90%

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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

Lighting ResultsFor Base and Alternate:• Total Electric Lighting Energy: 3.5 kWh/SF

– Average Office Building Energy: 2.6 kWh/SF

• Daylight Autonomy: 0%– % of the year when a minimum illuminance threshold is met

by daylight alone

• 0% of sensors have Daylight Factor > 2%– ratio of internal to external illuminance.

Base Alternate

% of sensors with Continuous Daylight Autonomy >40%

0% 11%

Next StepsFor Base and Alternate:• Total Electric Lighting Energy: 3.5 kWh/SF

– Average Office Building Energy: 2.6 kWh/SF

• Daylight Autonomy: 0%– % of the year when a minimum illuminance threshold is met

by daylight alone

• 0% of sensors have Daylight Factor > 2%– ratio of internal to external illuminance.

Base Alternate

% of sensors with Continuous Daylight Autonomy >40%

0% 11%

WHY?

WHY?

WHY?

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Information• Goal

What is a different acoustics after designing 3 skylights on the ground floor & basement? (Influence of 3 skylights to the ground floor & basement)

• Models Baseline: Original GSB Atrium Option: GSB Atrium with 3 skylights on the ground floor

• Metrics Two different models (Base vs. Option) Each different volume and surface of models

(2,735m³ vs. 5,270m³ )

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Assumption• Material Condition (Fixed)

• No influence from outside weather and noise

Assumption(Cont)• Sound Condition

Setup 1 speaker instead of noise for the each analysis

• No influence from existing the upper floors or not• No influence of the components and equipments except 50 clothe-covered chairs• Twice bigger volume due to the skylights in option• Consider only Sabine Algorithm for Reverberation time

Base vs. Option

• Sound Path (Low Frequency: 63Hz)

BASE: 21.7ms OPTION: 18.5ms

Base vs. Option(Cont)

• Sound Path (High Frequency: 16KHz)

BASE: 17.4ms Option: 15.7ms

Base vs. Option(Cont)

• Base Reverberation Time

Base vs. Option(Cont)

• Option Reverberation Time

Base vs. Option(Cont)

• Base Acoustic Response

16KHz: 47ms

63Hz: 47ms

Base vs. Option(Cont)

• Option Acoustic Response

63Hz: 89ms

16KHz: 95ms

Base vs. Option(Cont)

• Result63Hz

16KHz

Base OptionElapsed Time 21.7ms 18.5msSound Type Direct/Masked Direct/Masked

Base OptionElapsed Time 17.4ms 15.7ms

Sound Type Direct/Masked Direct/Masked

Base vs. Option(Cont)

• ResultBase Option

RT Value 500ms~690ms 950ms~1150

Ideal RT Value 800ms~1750ms 1000ms~1900ms

Estimated Decay

63Hz: 47ms 63Hz: 89ms

16KHz: 47ms 16KHz: 95ms

Conclusion• The RT of option model is in the ideal pink area, but the RT of

base model is below the area. The volume and surface of base model is easy to absorb the sound

rays.• There is no influence by 3 skylights to the basement• 3 Skylights change the result a little bit, but make a better

acoustic condition at the ground floor. Better RT result

• The base model has a longer elapsed time to completely disappear.

• The volume and the surface area bring a big different criteria for ideal condition. Ideal Pink Area: 800ms~1750ms vs. 1000ms~1900ms

For the next step

• Simulate the model with several different noise directions.

• Figure out the scale of preference about estimated decay time

• Find out other metrics to achieve a better result.

Costs, Schedule

Assumptions

• Building Explorer is right– U.S. Average Building Index ok– Automatically generated schedule ok

Results

Cost Breakdown

Material81%

Labor19%

Equipment0%

Material

Labor

Equipment

Material Costs

Labor Costs

$2081.36

Equipment Costs

$33.82

Schedule + 4D

4-Day Duration…

Day 1

Day 2

Day 3

Day 4

Energy Analysis

• Goal:– To determine energy consumption of building– To determine if natural ventilation will be

sufficient

Energy Analysis

• IES Virtual Environment– ApacheSim

• Simulates natural and mixed ventilation (MacroFlo)• Simulates building loads (ApacheLoad)• Simulates heat loss/gain (ApacheCalc)

Energy Analysis

• Assumptions:– Model inputs

• HVAC System: Mixed System w/ natural ventilation• Weather file: Moffett Field, Mountain View, CA• Building type: Library• Building construction: default room system• Thermal condition: Atrium Each Floor

– Fluorescent lighting – 1.5W/SF– People 65 from 10am-12am

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

Energy Analysis Results

• Carbon Emissions

CO2 emissions – base case

Total monthly emissions – 35,027 lbCO2

CO2 emissions – alternative case

Total monthly emissions – 46,587 lbCO2

Energy Analysis Results

• Energy Consumption

Energy Consumption – Base case

Monthly total – 146.053 MMBtuEnergy Consumption – Alternative case

Monthly total – 206.327 MMBtu

Energy Analysis Results

• Heating/Cooling Loads

Daily Heating and Cooling Loads – base case

Monthly total – heating: 31.088 MMBtu; cooling: 0MMBtu

Daily Heating and Cooling Loads - alternative

Monthly total – heating: 49.844MMBtu; cooling: 34.202MMBtu

Energy Analysis Results

• Room analysis – StacksPeak hourly room loads

Base Case Alternative Case

Room environmental conditions

Energy Analysis

• Next Step– More accurately capture behavior of building

• Determine actual operating hours• Determine actual HVAC system

– Type, set points, etc

• Create more accurate geometry

CFD Analysis

• CFD: Computational Fluid Dynamics– Analysis of fluid flows using numerical methods

and algorithms– Simulation of wind tunnel performance

CFD Analysis

IES Virtual Environment• MicroFlo (IES VE)

• Numerical simulation of air flow an heat transfer

• User definable obstructions• Interoperability with Virtual

Environment model

CFD Analysis

• Goals:– Determine effects of atrium on airflow in building– Predict occupant comfort

• Temperature gradient in rooms• Air velocity

CFD Analysis

• Model inputs:– Boundary Conditions defined during energy

analysis– Obstructions and heat generating component

• Ex: People, computers, radiators, etc

• Model outputs:– Air flow temperature, direction, and velocity– Graphical displays of temperature gradient and air

flow properties

CFD Analysis

• Progress– Problems with

importing gbXml geometry

• Inconsistencies developed between Revit and IES

CFD Analysis

• Next Step– Manipulate Revit model to properly represent

geometry in IES• Contact with IES tech support as well as Ben

Welle

Sample MACDADI Goodness