If you’ve heard the word “retrofit”, and have heard rumors that it’s something you need to know about, but have just been too busy with your job and family to take the time to teach yourself about it, let us help you out! We will cover the basics of retrofitting in this week’s blog. We will also cover where Consulting Engineers Corp. fits into the retrofitting world.
What is Retrofitting?
- Retrofitting is the reinforcement of certain buildings to make them better able to withstand the effects of an earthquake.
- Consulting Engineers is made up of engineers and has been in business for 47 years. Our head engineer has been involved in the engineering of over 100 million square feet of space in the San Francisco area.
What Buildings Need Retrofitting?
- The retrofitting ordinance does not cover all buildings.
- To come under the umbrella of the ordinance, buildings need to have a few characteristics. They are: if the building was built prior to 1978, has three or more stories, and has five or more dwellings in them. What these characteristics don’t mention specifically is the soft story.
- A soft story with three or more stories is particularly susceptible to collapse during an earthquake.
What is a Soft Story?
- A soft story is the lowest level of a building. In the San Francisco area, wooden-frame houses built before January 1, 1978, frequently have a bottom floor that is either retail space with a home above it or parking space with a home or apartments above the garage.
- Because the walls of the bottom floor are either glass or garage doors, this floor is weak, or soft, thus a soft story.
Why is Retrofitting Necessary?
- The ordinance and the retrofitting projects it requires have the goal of protecting property and life.
- During the Loma Prieta earthquake of October 17, 1989, 12,000 homes and 2,600 businesses were damaged. The 6.9 magnitude earthquake caused an estimated $6 billion in property damage, 37 deaths, and 3,757 injuries.
- There was a pattern in some of the damaged buildings that engineers noticed. Buildings with soft stories collapsed at a high rate.
- During the earthquake, buildings with soft stories experienced a collapse of the bottom floor and subsequently, the upper floors sometimes pancaked on top of each other.
- In some very lucky cases, the floors above the collapsed soft story remained intact but were still deemed uninhabitable.
What is done in a retrofit?
- There are several ways for the soft story to be strengthened. We’ll touch on a few of the more common actions that are taken in a retrofit project.
- After an inspection, your engineer will draw up a plan that could include some of the following things.
Moment Resistant Frames
- A moment resistant frame is a metal frame that is placed around the outside of garage doors or other entryways. The keys to a movement-resistant frame is the use of rigid metal and that the upright beams meet the horizontal beam at a right angle.
- The rigidity of the material and how they meet means that the frame columns of the frame will bend rather than the frame displacing laterally.
- A shear wall performs a similar function to the moment-resistant frame, but instead of resisting lateral movement with a rigid frame, with a shear wall, the entire wall acts to reinforce the structure. In a shear wall, there is a braced panel.
- Picture a timber frame with a plywood sheath. The power of this wall comes from the connections. The plywood exterior is firmly connected to the uprights, including a middle post and horizontal beams.
Post and Beam Reinforcement
- Older beams are not always connected to the beam they support correctly.
- Retrofitting by Consulting Engineers Corp. will strengthen this connection and strengthen the soft story.
- Repair is an important part of a retrofitting project. If your building has cracks in the foundation or buckling beams, the need for action is urgent.
- Protect your property and the lives of the people who exist within it with a retrofit.
- Consulting engineers performs repairs as well as retrofitting of undamaged buildings.
Who Does the Retrofitting Work?
- The inspection and plan should be done by a engineering firm, such as Consulting Engineers Corp.
- The actual work can be done by a construction company, but in the case of Consulting Engineers Corp., we do the actual construction work as well.
- Having Consulting Engineers Corp do both the planning and the actual construction has a clear benefit. If adjustments need to be made in the field, there will be no need to stop work for days or weeks while you wait for a engineer to reassess the plans.
Is There a Deadline?
- Yes. All buildings in need of retrofitting should have their permits pulled by September 15th. The ordinance that requires retrofitting was passed by the San Francisco city council in April of 2013.
Are There Other Benefits?
- Insurance companies can reduce your insurance premiums. Ask your insurance agent or company.
- The market value of your home or commercial building will also benefit from a retrofit. Buyers will want to know if the home has been retrofitted. And if it has not, not only could you lose interested parties, but even interested parties may have a hard time financing a home or business that has not been retrofitted.
- Buying a home is easier if it has been retrofitted. Lenders play a big role here. If your Probable Maximum Loss (PML) is low, you will more likely be able to find a lender.
- When you transfer your property, you will be required to sign a disclosure form about the structure’s foundation.
- If you are required to retrofit your building, and you follow through with it, you will be reducing your liability of anyone is injured and killed in your building.
- Attracting good tenants, and keeping them, will be easier if your rental property has been retrofitted.
If your home or commercial building has been identified as falling under the 2013 retrofitting ordinance, call us today and get started on the process. Don’t wait until the last minute! Protect your investment and avoid possible loss of life with timely retrofitting from Consulting Engineers Corp.