2009-02-17 6-B Power PointSoft-Story Retrofit Ordinance
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2/17/2009
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62% probability
of a major
earthquake within
the next 30 years
i n the Bay Area .
Housing
Unit Loss
6.9 Hayward
Fault
Earthquake
7,600 Alameda
Housing Units -
Uninhabitable
4,500 Housing Units
i n 250+ Soft-Story
Buildings
Soft-Story: Soft, Weak, Open Front
• 2- 4 Stories
• Often Parking
on Ground Level
• Wood or
masonry at 1St
floor
Soft-Story: Soft, Weak, Open Front
Primarily Residential Buildings
Soft-Story: Soft, Weak, Open Front
• Majority were constructed in the 1960's and early 1970's
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Potential soft Story Buildings
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Legend
- Soft Story Buildings (224) Water Parcels
Soft-Story Buildings:
Why are they a problem?
Heavy roofs, inadequate walls
and rigid upper stories lead to:
• Sideways Deformation
• Lower Level Collapse
Sideways Deformation
Sideways Deformation
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Sideways Deformation
1971 San Fernando Earthquake
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Sideways Deformation
1989 Loma Prieta Earthquake
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Sideways Deformation
1994 Northridge Earthquake
Soft-Story Collapse
Soft-Story Collapse
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Soft-Story Collapse
Gravity
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Soft-Story Collapse
1989 Loma Prieta Earthquake
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Soft-Story Collapse
1989 Loma Prieta Earthquake
Soft-Story Collapse
1989 Loma Prieta Earthquake
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Soft-Story Collapse
1989 Loma Prieta Earthquake
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Soft-Story Collapse
1994 Northridge Earthquake
Soft-Story Collapse
1994 Northridge Earthquake
Soft-Story Collapse
1994 Northridge Earthquake
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Soft-Story Collapse
1994 Northridge Earthquake
Retrofit scheme: add walls
Retrofit scheme: add frame
Retrofit scheme: enhance walls
Proposed Soft-Story Ordinance
Identify Soft Story Buildings
• Wood frame buildings with 5 or more residential unit.
• Built prior to adoption of 1977 Uniform Building Code
• Ground floor portion of structure contains parking or
other similar open floor space that causes soft, weak or
open wall lines with one or more stories above.
Adopt Retrofit Standards
• Chapter A4 2003 International Existing Building Code
+ 2007 California Historical Building Code (where
applicable
Proposed Soft-Story Ordinance
Notify Property Owners
Allow Property Owners an Opportunity to Appe~
Require Structural Assessment w/ in 18 months
• Report requirement accelerated
• Change of use;
• Permitted work valued at $100,000 or more;
• Building is identified as an Unsafe Building per
current California Building Code.
• Require Notification of Residents
• Tenants required to allow inspections
• 15 yr exemption from new hazardous designation
Proposed Soft-Story Ordinance
Engineering Report Review Fee - $750
Fee Reduction based on Early Report
Submittal:
No Fee -
75% Fee Reduction -
50% Fee Reduction -
25% Fee Reduction -
15 months early
12 months early
9 months early
6 months early
Permit Fees - $1,200 - $2,000
Permit Fees waived for projects submitting
for retrofit permits within 18 months of
designation of soft-story building.
Proposed Soft-Story Ordinance
• Minor modification to parking
standards to allow the elimination of
parking spaces where necessary to
complete soft-story retrofit, subject to
approval of Planning and Building
Director.
DSD is evaluating the use of CDBG
funds to help offset some of the
engineering costs.
Costs
• Mandatory Engineering Reports
expected to cost from $5,000 to
$20,000.
• Voluntary Retrofit costs expected
to range from $9,000 to $28,000 per
unit.
Consequences of
Earthquake Damage
to Soft-Story Buildings
Community Consequences
• Recovery takes time
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• Repairs will not be rapid
• Ghosts towns will appear
Community Consequences
• Damage can ignite fires
Loss of housing and
its effect on business
City of Alameda Consequences
Repair of city facilities will be costly an
will strain capacity to deal with the
repair of private buildings
• Revenues will be lost
• Property Tax
• Sales Tax
City of Alameda Consequences
Temporary housing for 4,500 households
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Owner Consequences
• Liability for injuries
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• Savings or borrowing capacity
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Loss of rental
income
• Existing debt
must be paid
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Tenant Consequences
Tr Displaced by damage
• Cost of repairs
could affect rent
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• Regional housing
will be affected
market
Fewer units for years
More demand for rental housing
Conclusion
• A Major Earthquake
Will Affect Alameda
in the Future
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• Soft-Story
Buildings
Will Fail
Photo: USC~S.~ D. L. L arver