Soft Story Los Angeles
In most earthquakes, many reinforced concrete structures suffer from minor to catastrophic damage. The most commonly observed damage is cracking and falling of the walls. But the most striking of these observations is the structural failures of multi-story buildings which have soft ground floors used for parking, called the “soft story.”
Since buildings with sound construction should not experience any major damage caused by ground motion, possible damage is due to inherent weaknesses in the structural system, design, detailing, poor material quality and unsound construction practice.
Why Are Soft Stories Inherently Weak?
A large opening in at least one wall, and a lack of central supports, make soft stories more susceptible to lateral forces from a large earthquake. When they fall, the second floor “pancakes” onto the first floor.
Shear wall panels won’t help much. Soft-story buildings need to be retrofitted with specially designed steel reinforcements.
Damage to reinforced concrete building structures can be attributed to the combination of the following reasons:
1. Soft story effects
2. Poor detailing of structural joints
3. Inadequate reinforcing steel
4. Inappropriate anchoring of beam and slab reinforcement
5. Insufficient reinforcing steel in columns with large aspect ratio
According to Caltech, there are more than 20,000 soft-structure apartment buildings in the city of Los Angeles alone. In 2015, Los Angeles responded by enacting one of the nation’s most far-reaching mandatory retrofit laws (Ordinance 183893), which identified roughly 13,500 wood-frame soft-story buildings and gave owners a set compliance window to strengthen them. Since then, the large majority of those buildings have been retrofitted, and cities across Southern California, from Santa Monica to West Hollywood, have adopted similar mandates.
These ordinances exist to prevent collapses like the one at Northridge Meadows Apartments, where 16 people died during the 1994 Northridge earthquake.
These are the steps to reinforce a soft story:
1. The concrete slab is broken up.
2. New reinforcement beams are setup into place underneath the old concrete poles that hold the
structure.
3. New concrete is being poured to hold the new beams.
4. The structure is stable again.
Contact Weinstein Retrofitting Systems for a Free Estimate & Inspection today!
About Weinstein Construction
Weinstein Construction has protected Southern California homes and commercial buildings since 1977, bringing nearly 50 years of specialized experience in foundation repair, house bolting, and earthquake retrofitting. Our team has completed more than 80,000 inspections and over 8,000 retrofit and foundation projects across Los Angeles and the surrounding region, delivering engineering-grade solutions built to meet California’s seismic standards. Every recommendation we make is grounded in decades of hands-on field experience and a commitment to doing the job right the first time. Learn more about our team or reach out anytime with questions about your foundation or earthquake preparedness.
