At RetroFitting 360 we specialize in soft-story buildings. In our experience we have seen that not every design created is suitable for meeting the standards in the Los Angeles soft-story retrofit program. Property owners often send us their plans looking for a quote on what the construction cost will be. In most cases we have to disappoint them by telling them their plans will not work.
Most of the time, the plans do not include enough reinforcements to protect the building in the event of a major earthquake. Too many people focus on just adding steel elements believing this will make their building sturdier. We have found that while the idea seems sound, in practice more enforced steel will just collapse weakened wood-framed buildings.
Part of our service is to draw up a retrofit plan that covers all of the elements you need to prevent your building from collapsing in the next earthquake. With a very important element that most people are missing, the existing wood frame. Replacing and reinforcing worn out or weakened wood frames needs to be part of the retrofit.
Why Steel is not Enough
Many of the engineering plans we see only focus on the strength and size of the steel being used in the retrofit (OMF/SMF moment frame, or OCCS/SCCS cantilever column). Installing steel elements is much easier than designing these elements to work properly. While it may make you feel safer knowing steel columns have been installed, if the retrofit designs do not include other elements they are flawed.
Without reinforcing the existing wood frame the steel columns could cause more damage during an earthquake rather than reducing it. Steel is a stiff element and during the trembling of an earthquake it may fall or collapse, demolishing the wood in its way. A major quake will push the wood components into the stiff steel and cause them to buckle or break.
Our engineers have years of experience retrofitting wood frame structures and know how to draw up plans that allow seismic loads to transfer correctly. Almost all of the plans created by other companies or even building owners do not take the wood frame itself into consideration.
In the event of a major earthquake your building could come tumbling down. Meaning all the money you invested in your retrofit would be for nothing. One of the biggest reasons for these design flaws is the wording of the Los Angeles soft-story retrofit ordinances which do not mention the need for reinforcing wood frames. For this reason, you will want to make sure you hire a retrofit company that is experienced with seismic retrofits for wood-framed structures.
Adding New Connections
A complete retrofit design needs to include the reinforcement of the wood frame that is already in place. One way to accomplish this is to add new connections, such as Simpson Strong-Tie LTP4/LTP5 and A34/A35 plates. This step helps to create a sturdy structure that transfers earthquake loads evenly and ensures the building will remain standing in the event of a major seismic event.
The first step is to remove the stucco covering the frame. This allows the contractor to assess the weak areas. We like to use a combination of wood boards to create a block and installing more steel connectors like Simpson Strong-Tie LTP 4 connectors over the new blocking. This provides a design that allows the subfloor to resist torsion and ties it to the existing dragline beam.
Creating Systems that Work Together
By installing wood blocking above a steel moment frame, we create a solid connection. This provides a transfer of the earthquake’s forces between the new frame and the existing building. After that, we run the wood blocking through the length of the structures. Now we have made more connections between the new and old structures which lets them work together. By creating a larger blocking frame it is more likely that the shaking of an earthquake will transfer smoothly back to the steel moment frame. Our team of specialists put a lot of thought and detail into crafting our retrofit designs. They work to ensure the soft-story retrofit will not just be strong enough but also smart enough to protect your building.
What We Offer
If your building is one that has been mandated to complete a soft-story retrofit by a Los Angeles retrofit contractor, we can get you started. When you set up an initial consultation, one of our professional contractors will do a walkthrough of your property to assess the current conditions. Then they will draw up a detailed step-by-step guide for you of what modifications need to be done so you will be in compliance with the ordinance.
RetroFitting 360, Inc. is a leading provider of soft-story earthquake retrofits in the Los Angeles area. Our experienced staff will focus on the most cost-effective and efficient construction solution to meet your needs. Our civil and structural professionals will draw up the necessary plans to modify the building that are needed for permits to be issued.
Our team is committed to turning your Los Angeles soft-story retrofit into as painless a process as we can for you and your tenants. If you are worried about the stability of your building, or you received a letter from the city to comply with the mandatory Soft-Story Retrofit Program we can help. Contact us today to schedule a free inspection of your property and find out about the cost-effective solutions available to you.