Non-ductile concrete buildings are considered to be the most dangerous structures during an earthquake. When Los Angeles introduced its mandatory seismic retrofit program, many non-ductile concrete buildings were included. Over 1,000 of these types of structures are located throughout the city. During a major earthquake, they are the buildings most likely to collapse in on themselves. Retrofit contractors throughout the area are needed to make these buildings safer.
LA’s seismic retrofit program is well into its fourth year. Recent estimates show that only 14% of the soft-story retrofits have been completed. But, a whopping 0% of the non-ductile concrete retrofits have even been started. While the deadline for these concrete buildings is further out than for the soft-story buildings, it is frightening that most of the owners have even begun the process.
What is a non-ductile concrete building?
These buildings are considered dangerous for two main reasons. One, most of them were built before 1977 before seismic building codes were in place. Two, the concrete used in their frames has become brittle over the years and is at risk of cracking and breaking during the shaking forces of an earthquake.
Most of these buildings have floors/and or roofs made of concrete that are only supported by the concrete walls. If any of the walls or the floor cracks, the structure can quickly collapse. Sadly, these types of buildings are found throughout the world and are the cause of more fatalities during an earthquake than any other.
How earthquakes can cause damage to concrete buildings
The city of Los Angeles lies on a few fault line, the largest being the Santa Monic Fault Line. When a fault line ruptures it causes movement in the earth surrounding it. How far this movement and shaking occurs, depends on the severity of the quake. But earthquake can cause major damage to city structures in other ways.
A fault that ruptures under, or near, the building can cause a reduction of soil. This means there is less weight bearing soil under the building and it could “sink” into the ground. Structures built near a hill or mountain can be damaged if the earthquake causes a landslide. Or, if a body of water, such as a lake or the ocean, is nearby, the earthquake can cause larger waves to hit the structure and may lead to flooding and water damage.
The purpose of the Los Angeles retrofit program
In 2015 the city passed two new ordinances designed around seismic building codes. The devastation caused by the Northridge earthquake in 1994 had a huge impact on the creation of this program. Whole city blocks were destroyed and 60 people lost their lives. The purpose of the retrofit program is to prevent that from happening in the future.
San Fernando Valley is known as earthquake central. The valley can experience up to 100 mild to moderate quakes in a year. In older buildings, even a mild earthquake can cause some damage. The other purpose of the retrofit program is to improve the city’s resilience after a natural disaster.
Timeframe to comply with the retrofit program
The timeline between soft-story buildings and non-ductile concrete buildings is very different. City officials mailed out notices to comply to all of the property owners of buildings they deemed to be at risk. If you received one of these letters, you have three years from its date to file a completed LADBS Checklist along with supporting documents to the Los Angeles Department of Building & Safety.
You have 10 years from the date of the notice to submit the following:
• Proof of previous retrofit, or
• Structural analysis and detailed plans showing full compliance, or
• Plans to retrofit, or
• Plans to demolish.
Then you have 25 years from the date of the notice to either have the retrofit completed or to demolish the building.
How do I start my retrofit?
The first thing you need to do is to hire a reliable company that specializes in seismic construction. Make sure to check how long they have been in business, how many similar projects have they completed, and ask for their insurance certification. Most retrofit contractors will be happy to supply you with any documentation that you ask for.
The first step is to have your building inspected to determine how much work needs to be done to bring it up to the current codes. Once the inspection is done, your contractor will put together a detailed work plan for you. This plan should include designs for the retrofit, options for you to choose from, an estimate of the cost, and a timeline for how long the work will take to complete.
Before the work begins
Before any construction can begin, the retrofit designs must be submitted to the city for approval and an application for a work permit has to be filed. It typically takes about 30 days for both of these to be approved. If you are a landlord with tenants in the building, you will also need to fill out and submit a Tenant Habitability Plan and file that with the Los Angeles Housing + Community Investment Department.
If a THP is needed, you cannot begin any construction until 60 days after it is served to your tenants. They have 15 days from the day of service to appeal anything in the plan that they don’t agree with. Depending on the scope of the work needed to retrofit your building, tenants may have to be temporarily relocated before construction begins.
What we offer
At RetroFitting 360 our professionally trained soft-story retrofit contractors in Los Angeles have been improving the vulnerability of many buildings and apartments throughout the city. We offer a free initial consultation to get you started. Once that is complete, we will provide you with a detailed work plan that includes retrofit options for your property, an estimated cost of the work, and a timeframe for when it will be completed.
We know that the retrofitting process can be confusing and quite long. We will work with you every step of the way. We handle the retrofit design, the application for the construction permit, filling out and filing the THP, and even contacting the city inspector at the end of the job. If you have any questions, please give us a call today.