2008-12-02 8-C Power PointSoft Story Retrofit
City of Alameda
62% probability of a
major earthquake
within the next 30
years i n the Bay Area .
ABAG estimates
Alameda will have up to
7,600 uninhabitable
housing units following
a 6.9 earthquake on
the Hayward Fault
Soft Story : Soft,
I. 2- 4 Stories
. Often Parking on Ground Level
• Wood or masonry at 15t floor
• Primarily Residential
• Majority in 1950's to 1970's
ea k,
pen Front
Soft Story: Why are they a problem?
Heavy roofs, inadequate walls and
rigid upper stories lead to:
• Sideways Deformation
• Lower Level Collapse
Sideways Deformation
EQ
Sideways Deformation
1971 San Fernando Earthquake
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Sideways Deformation
1989 Loma Prieta Earthquake
Soft Story Co I I a pse
Gravi
EQ
Soft Story Co I I a pse
1989 Loma Prieta Earthquake
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Soft Story Co I I a pse
1994 Northridge Earthquake
Retrofit scheme: add walls
Retrofit scheme: add frame
Retrofit scheme: enhance walls
Consequences of
~thquake Damage to
Soft Story Buildings
jai
Community Consequences
Recovery takes time
• Repairs will not be rapid
• Ghosts towns will appear
• Replacing buildings considered non-
conforming face conflicting community
goals
• Damage can ignite fires
• Loss of housing and its effect on
business
City of Alameda Consequences
Revenues will be lost
• Property Tax
• Sales Tax
Repair of city facilities will be
costly and will strain canacity to
deal with the repair
buildings
i
of private
Temporary housing for 7,600
Households
Owner Consequences
• Liability for injuries
• Cost of repair
• Insurance?
• Savings or borrowing capacity
Loss of rental income
Existing debt must be paid
Tenant Consequences
Displaced by damage
• Regional housing market will
be affected
• Fewer units for years
• More demand for rental housing
Cost of repairs could affect rent
Existing debt must be paid
• Right to know
Proposed Soft Story Prog ra m
• Identify Buildings Subject to the
Soft Story Program
• Wood frame buildings with (5) or more
residential units
• Built prior to December 15, 1985
• 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.
Establish Retrofit Standards
• Chapter A4 2003 International Existing
Building Code + 2007 California Historical
Building Code (where applicable)
Proposed Soft Story Prog ra m
• Notify Property Owners
• Allow Property Owners an Opportunity to Appeal
• Require Notification of Residents
• Require Structural Assessment w/in 2 Yrs of Designation
• Report requirement accelerated
• Due to sale of property
• Permitted work valued at $100,000 or more
• Change of use
• Prior to re-occupancy if vacant for more than 6
months
• Tenants required to cooperate and allow inspections
• 15 yr exemption from new hazardous designation
How Many Soft Story Buildings?
Soft Story Study
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527 buildings potentially soft story.
Building Inspectors have begun identifying soft story buildings.
Timeline
10/09/08 -Public Workshop
• 50 + attendees
• 11 / 19/ 08 -Soft Story ID Begins
• 12 / 02 / 08 -Council Presentation
O 1 / ? / 09 - 2nd Public Workshop
02/ 17/09 -Ordinance 1St Reading