Loma Prieta Damage to Housing

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1 Housing in Berkeley 46,875 housing units in Berkeley (2000 Census) 45% - single-family homes 21% - small apartment buildings (two to four units) 33% - larger apartment buildings (five or more units) Approximately 25,000 rental units 13,000 units may be made uninhabitable after a major earthquake on the northern segment of the Hayward fault Soft story buildings make up a disproportionate percentage of the 13,000 units Most built before modern building codes 1

2 Loma Prieta Damage to Housing Loma Prieta Most of the damaged single-family homes were repaired within 2 years. Only about half of the multi-family units had been repaired or replaced within 5 years. 2

3 Berkeley s Vulnerable Buildings Un-reinforced masonry buildings (URMs) Non ductile concrete buildings (lacking steel reinforcement and flexibility) Tilt-ups (concrete warehouses with wood frame roofs) Wood frame homes with unreinforced cripple walls and/or located on hillsides * Soft story apartment buildings * * primarily residential buildings 3

4 Soft Story Buildings Apartment buildings Tuck under parking or store fronts Large openings in walls of ground floor No shear walls on lowest floor 4

5 How to Mitigate Seismic Hazards Identify buildings, by type and use Educate the public and policy makers Assess seismic weaknesses of specific buildings Retrofit 5

6 Consequences of not retrofitting Death and injury Loss of housing- temporary and permanent Loss of rental income Loss of business license revenue Loss of of property tax revenue Impact on businesses Impact on university Ghost town effect like Northridge 6

7 Whose Problem is it? Tenants Building Owners City of Berkeley University of California Business community It s Everyone s Problem! 7

8 Mitigation Programs in Berkeley URM retrofit ordinance 90% of 700 buildings identified now in compliance 10% or less are residential Retrofit of City and School buildings Transfer tax rebate for residential buildings City refunds up to 1/3 of the transfer tax for retrofit, approaching $1,000,000 annually Approximately 35% have added anchor bolts and plywood shear walls in the crawl space 1996 Survey to identify soft story buildings with >4 units and tilt-up buildings 2001 Soft Story Assessment Project 8

9 Soft Story Data 400 buildings in Berkeley with 5 or more units 5,000 units Very vulnerable in an earthquake Sidewalk assessment of 150 buildings 9

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11 Soft Story Seismic Vulnerability by Building 250 Number of Buildings Severe Considerable Moderate Minor 11

12 Retrofit Effect on Parking 2% Number of 3225 Units in 146 Building Sample Losing Parking Spaces Due to Retrofit 3176 Units Retaining All Parking 49 Units Losing Parking 98% 12

13 The Soft Story Project Goals To accurately and thoroughly assess vulnerability To raise community awareness of the risk To recommend a plan of action To retrofit buildings and protect our community To serve as a model for addressing other vulnerable buildings in Berkeley and to other communities 13

14 Soft Story Mitigation Proposal - Phase 1 Adopt the list of soft story and tilt-up buildings as an inventory of potentially hazardous buildings Provide for an appeal mechanism Adopt technical standards based on IEBC Appendix Chapter IV Require notification for residents and/or posting of warning signs Require an assessment by a qualified design professional within 2 years 14

15 Soft Story Mitigation Proposal - Phase 2 Adopt program for retrofit after phase 1 Elements to be determined may include: designation of risk categories timelines anddeadlines for retrofit other triggers for retrofit such as change of ownership or large renovation incentives and sanctions 15

16 Costs Engineering reports expected to cost from $2,000 to $10,000 Retrofit costs vary by adopted standards San Jose study estimated costs of retrofit: $3,000 to $9,000 per unit for Life Safety,similar to proposed standards $14,000 to $20,000 per unit for achieving Limited Downtime Actual costs of proposed Risk Reduction standard to be determined based on Phase 1 and other cities experience & state codes 16

17 Program Development Schedule Phase 1 Presentations to Boards, Commissions & City Council Outreach to Community Winter/Spring 2005 Educational forum Meetings with Stakeholders Consideration by Boards, Commissions & City Council - Spring/Summer 2005 Start-up of program - Early 2006 Final Engineering Reports Early

18 Program Development Schedule Phase 2 Analyze information on vulnerability and retrofit in Phase 1 engineering reports Review other programs Educate and get input from public and stakeholder groups Adopt retrofit program 18