Over the past several decades, earthquakes in Hanshin, Mexico City, Northridge, Loma Prieta, and Christchurch have underscored the poor seismic performance of soft-story and non-ductile concrete buildings. The weakened wall lines of the former and the inadequate lateral resistance of the latter pose a grave threat to life and property, and in 2015, the Los Angeles Municipal Council passed legislation to address these weaknesses in the city’s buildings.
Effective November 22nd, 2015, Ordinance 183983 amended the Los Angeles Municipal Code with an introduction of mandatory earthquake hazard reduction standards. Aimed at wood-frame structures with soft-story and concrete non-ductile buildings, the new regulations impose mandatory retrofit measures.
Soft-story is a dangerous condition where the ground-level structure of a building is weakened by large openings. In multi-level buildings, it may be caused by tuck-under parking lots or large, open lobbies. In single-family residential homes, a typical soft-story is caused by a room situated over a garage door opening. Regardless of a building’s size, the soft-story condition has proven to be a threat to life and limb due to its inability to withstand earthquake loads.
LA’s earthquake retrofit ordinance targets multi-story wood-frame structures built before 1978, specifically those with parking or other open floor areas on the ground floor and one or more stories above the open space. Residential buildings with 3 dwelling units or less are exempt from these regulations.
If your building falls within the confines of LA’s earthquake retrofit ordinance, you will receive a written compliance order from the city’s Building Department. The order will specify your building’s priority designation, time limits and alternatives for compliance.
If you’ve received such an order from the city, you must complete the following tasks within the timelines below:
- 1. Within 2 years of receipt - submit proof of previous retrofits, retrofitting or demolition plans
- 2. Within 3.5 years of receipt - obtain construction or demolition permit
- 3. Within 7 years of receipt - complete retrofit construction and obtain the Certificate of compliance.
Are you wondering where to begin? Calling a licensed engineer is a good starting point for your seismic retrofit. An engineer’s analysis is mandatory and will pinpoint the structural weaknesses in your building’s lateral load path and help determine the necessary retrofit measures. If the engineer finds that the building does not meet the minimum seismic criteria specified in the ordinance, the owner can either demolish the building or perform adequate structural alterations.
Your retrofitting options may include installing shear walls, adding reinforced concrete grade beams and steel columns, or using steel moment frames. Some of these may be more appropriate than others based on your building’s structural systems and layout.
Other things to keep in mind when choosing an approach are costs and time. You want to minimize disruption to your building’s functions and resume operations as soon as possible. An experienced engineer will take budget, schedule, and constructability into account before recommending the most suitable course of action.
Non-ductile concrete buildings are the other target of LA’s earthquake retrofit ordinance. These are older concrete structures that lack lateral resistance ability because of inadequate steel reinforcement in their members. Several recent earthquakes, such as the Northridge Earthquake, the Great Hanshin Earthquake, the Mexico City Earthquake, and the Christchurch Earthquakes, serve as tragic evidence of older concrete buildings’ poor seismic performance.
Most concrete buildings erected before 1976 are non-ductile, and LA’s retrofit ordinance pertains to concrete buildings built under permits pulled before January 13th, 1977. If the city sends you an order to comply, you’ll have to meet the following compliance timelines to avoid penalties:
- 1. Within 3 years of receipt - complete and return the LADBS checklist issued to you with the order
- 2. Within 10 years of receipt - submit proof of previous retrofits, plans to retrofit, or plans to demolish
- 3. Within 25 years of receipt - complete retrofit construction and obtain the Certificate of Compliance
If you’ve received a compliance order, you must inform any residential or commercial tenants that the building has been deemed seismically unsafe. Next, hire a licensed engineer to evaluate your building, complete the LADBS checklist, and submit it to the city with supporting documents. After the structural analysis, an engineer can devise a retrofit plan.
Seismic retrofit measures for non-ductile buildings may include the addition of concrete shear walls or steel moment frames or retrofit existing seismic connections to better tie the building’s vertical and horizontal members together and improve the structure’s lateral resistance. This type of work is usually disruptive, but with careful planning, your design team can mitigate its effect on the building’s function.
Are you worried about the costs of retrofitting? The Property Assessed Clean Energy (PACE) program may help you obtain the necessary funds. The program allows owners of residential and commercial buildings to get financing for seismic retrofit projects and repay the money through the property tax bill. To find out if your building qualifies, call (877) 785-2237 or email firstname.lastname@example.org.
If you own a residential building that’s been slated for a retrofit, you can share the retrofit costs with your tenants. Thanks to Ordinance 184080, you can pass 50% of the cost of retrofit work to your tenants through a temporary rent increase. Click here to find out more.
As an additional incentive, any non-compliant MEP services you uncover during the retrofit are exempt from mandatory upgrades unless they pose an immediate threat to life or property.
How Can Design Everest Help
As of November 1st, 2019, Los Angeles has 1,223 non-ductile and 12,658 soft-story buildings in various stages of compliance with the retrofit ordinance. If your building is one of these, you have no time to waste: the retrofits are mandatory and have a proven ability to save lives and property.
Our engineers at Design Everest can help you through all the stages of a seismic retrofit, from the structural evaluation to the Certificate of Compliance. Contact us at (877) 892-0292 to discuss your project and receive a quote today. We can also connect you with a professional engineer or designer right away for a virtual consultation or virtual on-site!
*Note: The content published above was made in collaboration with members of Design Everest.
You must have an account to comment on the post. Register with us if you are an AEC professional!