ConsultingEngineers

State of the Art Technologies State of the Art Technologies

Base Isolation and Energy Base Isolation and Energy DissipatorsDissipators

Protection of Nonstructural Elements and Protection of Nonstructural Elements and Contents Contents

byby

SEAONC Protective Systems CommitteeSEAONC Protective Systems Committee

ConsultingEngineersOutlineOutline

•• Introduction and Overview Introduction and Overview –– Ron Mayes Ron Mayes •• Base IsolationBase Isolation

New Construction – Pat Ryan Retrofit – Simin Naaseh & Mason WaltersDesign & Analysis – Troy MorganUS Code Improvements – Rene VignosSimplified Design Procedure – Gordon WrayTesting – Ian AikenProgress in Japan – N. Kani

•• DampersDampersDevices – Ian AikenAnalysis Issues – Martin ButtonDesign Issues – Mark Sinclair

•• Comparison of Systems Comparison of Systems –– Ron Mayes Ron Mayes

ConsultingEngineers

“These Recommendations primarily are intended to safeguard against major failures and loss of life, NOT to limit damage, maintain functions, or provide for easy repairs.”

Quote from the Uniform Building Quote from the Uniform Building CodeCode

ConsultingEngineersProperty Damage RiskProperty Damage Risk

•• Repair Cost & Downtime Repair Cost & Downtime –– Nonstructural >> Nonstructural >> StructuralStructural

C d F P i il E/Q S f t f thCodes Focus Primarily on E/Q Safety of the

0

20

40

60

80

100

1

% o

f Tot

al C

ost

Structure 20%

Architectural/MEP80%

ConsultingEngineersInterstoryInterstory DriftDrift

∆∆

ConsultingEngineers

Caused by HighCaused by HighFloor AccelerationsFloor Accelerations

•• Piping & DuctworkPiping & Ductwork•• Ceiling & LightsCeiling & Lights•• Building EquipmentBuilding Equipment•• ElevatorsElevators•• ContentsContents

Caused by LargeCaused by LargeInterstory DriftInterstory Drift

•• Structural FrameStructural Frame•• Piping & DuctworkPiping & Ductwork•• Facade & WindowsFacade & Windows•• PartitionsPartitions•• ElevatorsElevators

Earthquake DamageEarthquake Damage

ConsultingEngineers

Drift Related Damage from Nisqually Drift Related Damage from Nisqually WA 2001WA 2001

ConsultingEngineers

Drift Related DamageAlaska 1964 & Olive View Hospital 1971

ConsultingEngineersDrift Related Damage – Northridge 1994

ConsultingEngineersGround and Floor Acceleration Ground and Floor Acceleration

Jan 17, 1994 Northridge Earthquake Santa Monica City Hall

CDMG Sta 24538, 360 Deg.

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

0.10

0.20

0.30

0 10 20 30 40 50

Time - Seconds

Acce

lerat

ion, g

-100%-80%-60%-40%-20%

0%20%40%60%80%

100%

0 5 10 15 20

Time - sec

Acce

lera

tion

%g

Ground Motion

Floor Response

Ground Motion is AmplifiedBy the Structure by a factor of 3 by a factor of 3

to 4 at the roof.to 4 at the roof.

ConsultingEngineers

Caused by HighCaused by HighFloor AccelerationsFloor Accelerations

•• Piping & DuctworkPiping & Ductwork•• Ceiling & LightsCeiling & Lights•• Building EquipmentBuilding Equipment•• Piping and Piping and DuctworkDuctwork

•• ElevatorsElevators•• ContentsContents

Caused by LargeCaused by LargeInterstory DriftInterstory Drift

•• Piping & DuctworkPiping & Ductwork•• Facade & WindowsFacade & Windows•• PartitionsPartitions•• ElevatorsElevators

Structural Earthquake Structural Earthquake DamageDamage

ConsultingEngineers

Acceleration Related DamageOlive Hospital 1971 (San Fernando Valley)

ConsultingEngineers

Acceleration Related DamageTV Studio

ConsultingEngineers

Acceleration Related DamageManufacturing Plant

ConsultingEngineersIn Summary...In Summary...

•• Earthquakes are Earthquakes are inevitableinevitable

•• Ground Forces are Ground Forces are amplified by a factor amplified by a factor of 3 to 4 at the roof.of 3 to 4 at the roof.

•• Consequences can Consequences can be expensive be expensive

Conventional Structure

ConsultingEngineers

Design Codes Focus on Limiting Design Codes Focus on Limiting DriftsDrifts

•• Design codes limit drifts Design codes limit drifts –– 2 to 3 inches per 2 to 3 inches per story story

•• Drift limits are intended to protect structural Drift limits are intended to protect structural frames and some nonframes and some non--structural elementsstructural elements

•• Seismic Design Codes have never required Seismic Design Codes have never required the SE to explicitly look at the SE to explicitly look at floor floor accelerationsaccelerations. .

ConsultingEngineers

The Result of the Code The Result of the Code FocusFocuson Drifton Drift

While Ignoring AccelerationWhile Ignoring Acceleration

ConsultingEngineers1994 Northridge Earthquake 1994 Northridge Earthquake

•• 31 Hospitals 31 Hospitals -- significant significant damagedamage

•• 9 Hospitals partially or fully 9 Hospitals partially or fully evacuatedevacuated

•• USC University Hospital in USC University Hospital in downtown LA downtown LA –– 1st isolated 1st isolated hospital no damage at allhospital no damage at all

•• Los Angeles County Hospital Los Angeles County Hospital less than 1 mile from the less than 1 mile from the USC isolated hospital had USC isolated hospital had $389 million in damage$389 million in damage

ConsultingEngineers

Significant $$$ Damage in Recent Significant $$$ Damage in Recent EarthquakesEarthquakes

•• Economic impact of the 1994 Northridge ($30B) and Economic impact of the 1994 Northridge ($30B) and 1995 Kobe ($200B) earthquakes caused a rethinking of 1995 Kobe ($200B) earthquakes caused a rethinking of the code design philosophy by SEthe code design philosophy by SE’’s.s.

•• Much of the downtime and damage costs was a result of Much of the downtime and damage costs was a result of nonstructural damage nonstructural damage

•• Future Codes Future Codes –– Performance Based Design Performance Based Design

•• Owner chooses desired performanceOwner chooses desired performance

ConsultingEngineers

The Future The Future -- Performance Based Performance Based DesignDesign

•• ATC 58 ATC 58 –– Earthquake performance will be Earthquake performance will be expressed in Deaths, Dollars and Downtime expressed in Deaths, Dollars and Downtime ––language the owner understandslanguage the owner understands

•• PBD has two very different objectivesPBD has two very different objectivesTo minimize first costs if only life safety is desired

To minimize downtime and the cost of damage if higher performance is desired

•• Designs will focus on minimizing both interDesigns will focus on minimizing both inter--story story drift and drift and floor accelerationsfloor accelerations for higher for higher performance performance

ConsultingEngineers

Present GenerationPresent GenerationPerformance ObjectivesPerformance Objectives

•• Specification of :Specification of :

PerformanceObjective

=

• Design Hazard (earthquake ground shaking)

GroundMotion

x% - 50 years PerformanceLevel

+

• Acceptable Performance Level(maximum acceptable damage, given that shaking occurs

ConsultingEngineers

Present Generation Present Generation Performance LevelsPerformance Levels

Joe’sBeer!Beer!Food!Food!

Beer!Beer!Food!Food!

Joe’sBeer!Beer!Food!Food!

Joe’s

FullyFunctional

ImmediateOccupancy

LifeSafety

CollapsePrevention

ConsultingEngineersPerception of a GuaranteePerception of a Guarantee

It was supposedto provide

Immediate Occuancy!!

I followed the guidelines???

Maybe I should call

myattorney!!!

ConsultingEngineersPerformance Based Design Performance Based Design –– Damage and DowntimeDamage and Downtime

Damage or Loss0% 100%

Time out of servicenone permanent

Joe’sBeer!Beer!Food!Food!

Beer!Beer!Food!Food!

Joe’sBeer!Beer!Food!Food!

Joe’s

FullyFunctional

ImmediateOccupancy

LifeSafety

CollapsePrevention

ConsultingEngineersVarious Expressions of Repair CostsVarious Expressions of Repair Costs

DV

IM

DMEDP

(d) Contributions to total cost for scenario

structural

nonstructural

(a) Expected cost of damage for M7 scenario

$5.2M

(b) 90% confidence damage cost does not exceed threshold for given hazard level

$8.0M

(c) 80% probability damage will be between

$3.3M - $8.0M

ConsultingEngineers

Conventional Structure Isolated Structure

Comparison of Response

ConsultingEngineersBase Isolation DesignBase Isolation Design

Isolated Structure

•Accelerations reduced by 3 to 7 across the isolators

•Accelerations reduced by 8 to 12 at the roof

•Deformation occurs across the isolators rather in the frame –drifts are minimized

ConsultingEngineersAcceleration Response SpectrumAcceleration Response Spectrum

Period Shift

Period

Acc

eler

atio

n

ConsultingEngineersForce Displacement TradeForce Displacement Trade--OffOff

PeriodShift

Displacementof Structure

Force to Structure

Period of Vibration

Forc

e o

r D

ispl

acem

ent

ConsultingEngineersSimplified Design Procedure Simplified Design Procedure

•• Current US codes provide equations for Current US codes provide equations for limits on the forces and displacements. limits on the forces and displacements.

•• SEAONCSEAONC’’ss Protective Systems CommitteeProtective Systems Committee’’s s proposal for a simplified or preliminary proposal for a simplified or preliminary design procedure will quantify the design design procedure will quantify the design forces and displacements considering all of forces and displacements considering all of the code requirements the code requirements –– property variations, property variations, torsion etc. torsion etc.

ConsultingEngineers

Cover Rubber

Energy Dissipation Core

Steel Reinforcing Plates

Internal Rubber Layers

Bottom Mounting Plate

(Top Mounting Plate Not Shown)

ElastomericElastomeric Seismic Isolator Seismic Isolator –– LRB or LRB or HDRHDR

ConsultingEngineersIdealized Idealized HysteresisHysteresis LoopLoop

Force

Displacement

Plastic Deformation

ConsultingEngineers

CENTER POSITION

DISPLACED POSITION

Friction Pendulum BearingFriction Pendulum Bearing

ConsultingEngineers

Friction BasedFriction BasedBilinear HystereticBilinear Hysteretic

ConsultingEngineers

Elastomeric Backed Slider

ConsultingEngineers

Elastomeric Backed SliderElastomeric Backed SliderExample Example HysteresisHysteresis LoopLoop

ConsultingEngineers

Key System Design ParametersKey System Design ParametersGordon WrayGordon Wray

Force

Displacement

K2

Vy

ConsultingEngineers

No Replacement after an Earthquake No Replacement after an Earthquake Ian Aiken Ian Aiken

•• Prototype testing takes the isolators through Prototype testing takes the isolators through 3 or 4 maximum credible earthquakes3 or 4 maximum credible earthquakes

ConsultingEngineers

6 Story Isolated Computer Center –Kobe Japan

ConsultingEngineersBase Isolated Base Isolated –– Computer CenterComputer Center

ConsultingEngineers

6 Story Conventional Office Building Next Block

ConsultingEngineersConventional Office Building Conventional Office Building

ConsultingEngineersEarthquake Force Reduction Earthquake Force Reduction –– 10 10

ConsultingEngineers

Comparison of Applications in the US Comparison of Applications in the US and Japanand Japan

•• US US –– 100 building applications100 building applications

•• Japan Japan -- 1500 building applications1500 building applications

•• Issues include:Issues include:societies attitude to earthquake safety, US focus on first rather than life cycle costs, lack of awareness of the performance of a code designed building

•• Dr. Kani will overview progress in JapanDr. Kani will overview progress in Japan

ConsultingEngineersUS ApplicationsUS Applications

•• 55% Government55% Government•• 45% Private sector45% Private sector•• 60% New Buildings60% New Buildings•• 40% Retrofit of Existing 40% Retrofit of Existing

BuildingsBuildings•• 10 Hospitals10 Hospitals

ConsultingEngineersHospitalsHospitals

USC Teaching Hospital

Long Beach VA Retrofit

San Bernardino County

Los Angeles County

ConsultingEngineers

Government Buildings

Salt Lake City and County South Carolina State Capitol

San Francisco City hall Oakland City Hall

ConsultingEngineers

Channing House Evans & Sutherland

Hitech & Biotech ManufacturingOffice & Residential

Autozone HeadquartersAmgen

ConsultingEngineers

Computer Centers, Libraries & Corporate Headquarters

Hughes Aircraft

Rockwell Computer Center Kaiser Computer Center

University Library

ConsultingEngineersDesign Awareness IssuesDesign Awareness Issues

•• Building will move +/Building will move +/-- 20 to 30 inches20 to 30 inches

•• Piping Piping -- loops and flexible couplersloops and flexible couplers

•• Building separation from adjacent structures Building separation from adjacent structures –– some innovative solutions have been some innovative solutions have been developeddeveloped

ConsultingEngineers

Isolator Locations Isolator Locations New Construction New Construction –– Pat Ryan Pat Ryan

ConsultingEngineersClosure DetailsClosure Details

ConsultingEngineersSan Diego County Emergency Operation CenterSan Diego County Emergency Operation Center

ConsultingEngineers

San Diego County Emergency Operation San Diego County Emergency Operation CenterCenter

ConsultingEngineersUSC HospitalUSC Hospital

ConsultingEngineersUSC HospitalUSC Hospital

ConsultingEngineersSan Bernardino Law & Justice Center

ConsultingEngineersNew San Francisco LibraryNew San Francisco Library

ConsultingEngineers

San Francisco Airport and San Bernardino San Francisco Airport and San Bernardino Hospital Complex Hospital Complex –– 5 Isolated Buildings5 Isolated Buildings

ConsultingEngineersKaiser Data Center Kaiser Data Center

ConsultingEngineersEvans and Sutherland Evans and Sutherland

ConsultingEngineersSome Innovative Framing Schemes - Japan

ConsultingEngineers

ConsultingEngineers

ConsultingEngineers

•• FunctionalityFunctionality

•• Contents ProtectionContents Protection

•• Investment ProtectionInvestment Protection

•• Historic PreservationHistoric Preservation

•• Design EconomyDesign Economy

Retrofit GoalsRetrofit Goals

ConsultingEngineers

Retrofit Design IssuesRetrofit Design IssuesSimin Naaseh and Mason WaltersSimin Naaseh and Mason Walters

•• Capacity of Existing BuildingCapacity of Existing Building

•• Plane of IsolationPlane of IsolationFoundation Level

Basement Level

Top or Mid-Height at Columns

ConsultingEngineersBenefits of Base Isolation RetrofitBenefits of Base Isolation Retrofit

•• Eliminates/Reduces Ductility DemandEliminates/Reduces Ductility Demand

•• Work is Primarily Confined to BasementWork is Primarily Confined to Basement

•• Building Can Continue to be OccupiedBuilding Can Continue to be Occupied

•• Often the Most Economic SolutionOften the Most Economic Solution

ConsultingEngineers

ConsultingEngineers

ConsultingEngineers

ConsultingEngineers

Salt Lake City and County

ConsultingEngineersSalt Lake City and County

ConsultingEngineersLong Beach VA Hospital - Retrofit

ConsultingEngineers

Campbell Hall - Monmouth OregonOldest Building in Oregon State University

ConsultingEngineers

Mackay School of Mines Library University of Nevada - Reno

ConsultingEngineers

Conexant Chip Manufacturing – Newport $1 Billion in Products – Full Underpinning

ConsultingEngineersBerry St Berry St –– 2 Story Base Isolated Addition2 Story Base Isolated Addition

ConsultingEngineersBerry St. Addition Berry St. Addition

ConsultingEngineersElevator DetailsElevator Details

ConsultingEngineersPiping and Electrical DetailsPiping and Electrical Details

ConsultingEngineersLarge Interface PipesLarge Interface Pipes

ConsultingEngineersFlexible and Looping Piping DetailsFlexible and Looping Piping Details

ConsultingEngineers24 Inch Chiller Pipe24 Inch Chiller Pipe

ConsultingEngineersPiping Details from VA HospitalPiping Details from VA Hospital

ConsultingEngineersPiping Details from VA Hospital Piping Details from VA Hospital

ConsultingEngineersConduit DetailsConduit Details

ConsultingEngineersBase Isolation TechnologyBase Isolation Technology

•• With 1600 isolated projects worldwide all the With 1600 isolated projects worldwide all the interface issues have been addressedinterface issues have been addressed

•• Base isolation is most economic method of Base isolation is most economic method of achieving operational performance objective achieving operational performance objective

•• Operational performance is difficult and more Operational performance is difficult and more expensive with conventional designexpensive with conventional design

ConsultingEngineersCode Requirements Code Requirements -- Rene VignosRene Vignos

•• More sophisticated engineering analysis More sophisticated engineering analysis

•• Geotechnical Geotechnical –– need site specific study need site specific study

•• Peer review is required by the code and needs to be done Peer review is required by the code and needs to be done concurrently with the design.concurrently with the design.

ConsultingEngineersSimplified Design Procedure Simplified Design Procedure –– Gordon Wray Gordon Wray

•• Base isolated structure is a structural system Base isolated structure is a structural system that is closest to SDOFthat is closest to SDOF

•• Only structure in US codes that is required to Only structure in US codes that is required to have nonhave non--linear time history analysis linear time history analysis

•• SEAONC PSC believes that the design and SEAONC PSC believes that the design and analysis process must be simplified for more analysis process must be simplified for more widespread use of the technologywidespread use of the technology

•• Debut of an exciting development by PSCDebut of an exciting development by PSC

ConsultingEngineersDesign and Analysis Process Design and Analysis Process –– Troy Morgan Troy Morgan

•• Biggest impact is on structural engineer. They must Biggest impact is on structural engineer. They must determine the amount of movement as quickly as determine the amount of movement as quickly as possible for the architect and MEP team. possible for the architect and MEP team.

•• Architect needs to deal with the separation issues Architect needs to deal with the separation issues and whether or not to feature or hide the fact the and whether or not to feature or hide the fact the building is isolated. building is isolated.

•• Isolation specialist works with other disciplines on Isolation specialist works with other disciplines on architectural, mechanical and electrical details. architectural, mechanical and electrical details.

•• PrePre--selection of the isolation system is desirable on selection of the isolation system is desirable on both hospital and fast track projects. both hospital and fast track projects.