understanding the seismic vulnerability of water systems
TRANSCRIPT
Understanding the Seismic Vulnerability of Water Systems –
Lessons Learned and What You Can Do
Region
al W
ater Provide
rs
Consortiu
m Boa
rdDon
ald Ba
llantyne
Octob
er 2, 2013
Overview• Oregon Resilience Plan• Historic earthquake
performance• Seismic risk and earthquake
hazards– Liquefaction– Cascadia Subduction Fault– Portland Hills Fault– Canby‐Moalla Fault
• Expected performance • Desired performance• How are we going to get there?• Emerging seismic resistant pipe• Questions
Oregon Resilience Plan• After 2 weeks without services, people leave;
many don’t come back• Keep the supply and transmission system
operable (fire suppression)• Restore distribution within
2 weeks
Historic Earthquake Performance• Tohoku, Japan 2011 ‐
40+ days
• Christchurch, New Zealand 2011 –
40+ days• Kobe Japan, 1995 – 60 days
– 1,200 pipeline failures• Northridge, California 1994 –
13+ days
– 1,000 distribution failures
– 35 transmission main failures
Tohoku Earthquak e
Kanigawa WTP
Pipes
sheared
off (typ)
Utilidore
floated
Tohoku ‐
Pipe Performance
Failure of 2.4M DIP, Sendai
No failures in Kubota seismic joint pipe
Floating Sewers
Photo Credit SEAW
Tohoku, Japan 2011
JWWA Manual for Emergency Countermeasure
JWWA Emergency Water Supply Operations
Lining up at a base water supply facility
Water supply at an emergency medical establishmentSet up of canvas tanks
Emergency water supply vehicles – maximum of
430/day
Damage to Water Supply・Limited accessibility to gasoline, light oil, and kerosene.
・ Difficult to obtain fuel for electric generators, water trucks, official vehicles, and specialized task vehicles etc.
Water Purification
Plant
Electric Generator Operation Hours
Return of Electricity Type of Oil
Tank Capacity
（L)
Operational Hours/ Tank
Capacity
Moniwa 98 March 15 Kerosene 6,500 28.7
Kunimi 58 March 14 Light Oil 950 13.1
Nakahara 54 March 13 Kerosene 12,000 29.4
Fukuoka 68 March 14 Kerosene 10,000 29.9
Tohoku Fuel Shortage
Water Restoration Timeline ‐
Sendai
Distribution area restoration
Aftershock
occurred
★
Earthquake occurred
★
Distribution area restoration
Distribution area restoration
Began receiving w
ater from
the Sennan Senen R
egional Area to Sendai
★
Transmission pum
p failure
Main trunkline restoration
Distribution station restorationSennan Senen R
egional Area
water distribution secured by
rerouting water system
Received water from distribution station
The number of the w
ater suspension ×1,000 houses
Christchurch NZ Feb 22, 2011
City of 360,000 people
M6.3 Direct Hit
190 fatalities
CBD destroyed, 1,800 buildings demolished
55,000 residences damaged
$25‐$30B damage; 20% of GDP
Extensive liquefaction along the Avon River
Christchurch NZ
1645 water pipeline repairs
out of 1000 miles pipe
Most was AC pipe
Have moved to HDPE
300 km of sewer damaged
8 PS require replacement
Chemical toilets distributed to 30,000 residents
15
Kobe, Japan 1995 Pipe joint pull out due
to liquefaction
Over 1/2 of the failures were due to joint
pull out. Pipeline damage rates for the Kobe
earthquake are shown in the table below.
Failure Rates/km - Number of FailuresDIP CIP PVC Steel AC
PipeLlength (km) 1874 405 232 30 24Barrel 0 9 0.63 257 0.38 88 0.33 10 1.24 30Fitting 0 1 0.31 124 0.17 40 0.03 1 0.04 1Pulled Joint 0.47 880 0.49 199 0.33 76 0 0 0.37 9Joint Failure 0 2 0.06 25 0.5 115 0.07 2 0.08 2Joint Intrusion 0 5 0 1 0.01 3 0 0 0 0
Failure Mode
Kobe, Japan 1995 Lateral Spread
Resulting in Pulled Joint
16
Lateral spreading resulted in DIP joint separation
Liquefaction Damage to Treatment Plants
Higashinada Wastewater Treatment Plant, Kobe, Japan
1995
Buried Pipe Failure Jensen WTP 81”
Raw Line
Northridge 1994
Tank Damage – Elephant’
Foot
Buckling
Northridge 1994
Tank Damage
Rocking tank separated
piping
Inadequately attached roof slid
Northridge 1994
Wire Wrapped Concrete Tanks
Loma Prieta 1989
Regional Earthquake Hazards• Tsunami – only on the coast• Liquefaction• Cascadia Subduction Fault, (Magnitude 9.0);
500‐year recurrence (last event 1700)• Portland Hills; East Bank Fault (Magnitude 6.8)• Canby‐Moalla Fault
Tsunamis
Sendai WWTP Pump Station hit by tsunamis, Japan 2011
Liquefaction
Loss of bearingLoss of bearing
Liquefaction
Occurs due to shaking
Soil particles consolidate squeezing out water
Water pore water pressure increases reducing friction between soil particles
Soil becomes a viscous liquid
Costa Rica, 1991
Consolidated sand grains
Loosely packed sand grains
Initial Section
Lateral Spread
Deformed Section
Soil Blocks
“Floating”
on
Liquefied Material
Liquefied Material
X X X X XX X
Design pipeline to move with
the soil blocks – expand to
relieve strain and be dragged
through the ground.
Pipeline
Liquefaction
Liquefaction
Willamette,
Columbia,
Tualatin
Pacific Northwest Earthquake Source Zones
Cascadia Subduction Zone
500 year return period for full length
Most recent event 1700
25% probability within next 50 years
40% probability southern segment
Groundmotion Cascadia Subduction
Higher ground motions west of Portland
Will impact older/poorly engineered structures will fail
Long duration shaking will cause liquefaction
• Movement in the North American Plate
• Remnant from the northwest movement of the Pacific Plate
• Western Oregon rotating northwest
• Portland to Bellingham getting squeezed ~ 10 mm/yr
• Differential movement results in surface faults
Block Movement
Earthquake Faults
Surface fault ruptures could shear pipelines
Ground motions stronger near field damaging
Tanks & structures
Portland Hills Fault
Groundmotion
Fault Crossings
Recommendations from Resilient Oregon Plan
• Reset public expectations for recovery times• Require seismic assessments for all systems• Encourage water & fire agencies coordinate plans• Encourage upgrades; sanitary surveys & designs• Encourage business continuity plans• Encourage essential support for employee families• Establish seismic design standards for pipelines• Clarify regulatory expectations during emergency• Encourage participation in ORWARN• Plan for emergency water distribution
Hazard
Quantification
•Groundmotion•Liquefaction
Component
Fragilities
Component
Impacts
•Functionality•Outage time
System Analysis•Capacity•Outage time
Business Interruption/
Societal Losses
•Daily outage per capita $•% GRP•Business specific losses
Seismic Assessments
Pipe Damage Relationships
ALA Repair Rate - PGD
0.000.501.001.502.002.503.003.504.00
0 10 20 30 40 50
PGD (inches)
Rap
air R
ate
(1,0
00 ft
) CIP
DIP
Steel
CIP
DIP
Steel
CCP
Repair Rate for Shaking Damage Repair Rate for Ground Deformation
Portland GIS Analysis Input
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1% 10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Peak Ground Acceleration
Prob
abili
ty o
f Fai
lure
Pipe Material/Facility Information
Damage/Fragility FunctionsLiquefaction Susceptibility
Ground Motion Scenario - Subduction Earthquake
Asset Inventory
Facility
Age (yrs)
Moved from UBC
Zone 2 to Zone 3
Component Reliabilities/Fragilities
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
PGA (g's)
Rel
iabi
lity
Pump Bldg.Control Bldg.ReservoirWellsWell Collection PipingMain PumpsSubstationControl EquipmentTotal
Example ‐
System Critical Facilities Status
Example ‐ Outage Maps
LADWP following Northridge
Develop Recommendations; Input into Capital Improvement Plan
• Identify vulnerable sections of transmission system – replace as required
• Identify vulnerable pipelines within distribution systems – replace with seismic resistant pipe
• Evaluate storage, pump stations – upgrade as required
• Schedule mitigation to achieve desired performance over 50‐years
Seismic Resistant Pipe• Modern pipe works well in competent soils• In liquefiable soils:
– Restrain joints– Allow for strain
relief
Ductile Iron Pipe (DIP) AWWA C‐150 with Restrained Joint (Field‐Lok
Gasket)
• Design to resist ground movement• Material strength and ductility • Restrained joint • Does not allow release of strain due to ground deformation
DIP Joint
Bell
GasketRetainer
Seat
Wedge DIP Joint
Spigot
zz
Ductile Iron Pipe Expansion Sleeve
• Expansion sleeve for strain relief• $900 ‐
8”; $1,200 –
12”
EBAA Ex‐Tend• Proposed “custom”
expansion sleeve –
hook into the bell with a split
harness; about half the above cost
EBAA Ex‐Tend
Japanese Seismic Joint DIP
• Restrained joint• Allows expansion/compression
PVC (C‐900) with 2X Deep Bell and Joint Harness
(Manufactured by Kubota)
• Vulnerable to corrosive soils • Expansion can be provided for strain relief
Polyvinyl Chloride (PVC) AWWA C‐900 with joint restraint
• Vulnerable to corrosive soils ?• No expansion allowed for strain relief
Bulldog Joint – “Wedge” Ring Embedded in Joint
Joint Harness – Add anode caps on bolts?
Molecularly Oriented PVC AWWA C‐909
• Stronger/more ductile than C‐900
• Telescope (compress) without loss of
hydraulic integrity
High Density Polyethylene (HDPE) AWWA C‐906 –
Fused Joint
• Excellent performance in Christchurch and Tohoku earthquakes
• Relieves strain through ductility
Summary• Water systems have been heavily damaged in past
earthquakes• Oregon is seismically active• The Oregon Resilience Plan is pushing to mitigate
vulnerable facilities within 50 years• Seismic vulnerability assessments can identify expected
damage and system performance in an earthquake• Implementation of developing pipe
materials can help provide resilient systems
