Earthquake Retrofitting FAQs

When it comes to your building, you may not know the right steps to take to ensure that your structure can withstand the damaging and often devastating effects of an earthquake. It can be challenging to know just what actions you should take if your building is susceptible to damage, and it can be even harder to determine if your building needs better protection to increase its seismic performance. For that very reason, we’re proud to bring our customers this comprehensive earthquake Retrofitting FAQ guide, so that you can rest assured knowing that you have all of the resources you need to take the proper precautions against an earthquake.

What Is Earthquake Retrofitting?

First let us tell a little bit about earthquake retrofitting, aka, seismic retrofitting and its techniques and strategies, as well as analysis. 

Earthquake retrofitting is the alterations of structures that had been built before making them resist the movements of earth surfaces and any kind of seismic activities. Because of the recent experiences with frequently encountered earthquakes in urban areas, seismic retrofitting keeps on spreading its necessity on structures. So the seismic engineers’ (earthquake engineer) function is constructing structures that will be able to avoid serious, large damages or collapse during earthquakes. And earthquake engineering is a scientific area connected with the natural environment, protecting society and also men-made surroundings from earthquakes through reducing the seismic risk to socio-economically allowed levels.

Retrofit techniques that are going to be mentioned below, can also be applicable for other natural phenomenons that may cause damage to the environment or humanity for example tornadoes, post thunderstorm severe winds or tropical cyclones, and so on. It is very important to limit the losses and hazards from non-structural elements as well as to know that there’s no earthquake-proof structure at all, however, seismic performance will be increased greatly with the right subsequent modifications and initial design or with the proper seismic retrofitting.

Earthquake Retrofitting Techniques

Earthquake Retrofitting Techniques are required for concrete constructions that are vulnerable to damage and failures by seismic forces. In the past 30 years, moderate to severe earthquakes occur around the world every year. These kinds of events are causing damage to concrete structures and also failures.

There are several exact categories of retrofitting techniques:

  • External post-tensioning

For the new structural systems, external post-tensioning retrofitting has been made during the past 10 years. U.S and Japan joint research program unbonded post-tensioning high strength steel tendons have been used to reach the system that has the self-centering ability of structural elements.

  • Base isolators

Base isolation is a combination of structural elements of an edifice that should decouple the building’s structure from the shaking ground.

  • Supplementary dampers

Supplementary dampers absorb the energy of motion and turn it into heat, although the oscillatory system resonant effects in structures that are rigidly attached to the ground.

  • Tuned mass dampers

TMD or tuned mass dampers employ mobile wights on several sorts of springs. These are for reducing wind sway in light and tall buildings. Such designs can be used to impart earthquake resistance in 8 - 10 story buildings that are prone to destructive earthquake-induced resonances.

  • Slosh tank

Slosh tanks are large containers of low adhesiveness fluid, for instance, water, that can be placed at areas in a structure where lateral swaying motions are compelling, for example, roofs.

During the seismic activities, the flowing substance in the tank is being sloshed back and forth through which the motion is controlled.

Earthquake Retrofitting Strategies

Seismic retrofit strategies are being developed since the past several decades following the availability of advanced materials and the introduction of new seismic provisions.

  • Increasing global capacity. This is basically done by the new structural walls or the addition of cross braces.

  • Depletion of the seismic demand by means of supplementary damping as well as the use of base isolation set of the working mechanism.

  • Growing the local ability of structural elements. The following strategy recognizes the intrinsic capacity among the existing structures and that’s why it adopts a more cost-effective approach to selectively expand the local capacity building of individual structural parts of a larger whole.

  • Selective weakening retrofit. This is a strategy that does not happen in a way someone would expect it to and it changes the non-flexible mechanism of the structure while recognizing the inherent capacity of the structure.

  • Accepting sliding connections, for example, passageway bridges to accommodate additional motion between seismically independent structures.

  • Addition of seismic friction dampers to simultaneously add damping and a choosable quantity of additional stiffness.


soft story retrofit Los Angeles


How do I know if my structure requires improvements?

At the Army of Builders, our team of in-house engineering professionals would be more than happy to pay a visit to your home or building and conduct a thorough assessment to determine the strength of your structure.
Now you can also find some of the most given questions below about earthquake retrofitting.

Can repairing help to increase the seismic performance of my foundation? 

Repairing your foundation can be an excellent way to increase your seismic performance. Because our structures sit on top of them, your foundation often serves as the first line of defense against seismic activity, which means that if it’s in the best possible shape, you can increase your seismic performance. 

Can I retrofit my home while remodeling it? 

You can retrofit your home whenever you wish. At the Army of Builders, we also offer home remodeling services, and for many of our clients, this is an appropriate time to retrofit your home for earthquake protection. And during home additions, we can also retrofit the existing structure, while working to build a new structure that is also well-protected against earthquakes.

I don’t know where to begin–how can I get started? 

When it comes to earthquake protection, it’s safe to say that it isn’t exactly the most common topic amongst homeowners. And in fact, many homeowners don’t know where to begin. For that very reason, our team here at the Army of Builders is always standing at the ready to provide our clients with everything they need to ensure that they make an informed decision when it comes to the structural integrity and seismic performance of their building. We’d be happy to talk to you about your building. Give us a call and reach out to us directly. We can even send a member of our in-house engineering team out to your property to take a look. We’d be happy to do everything we can to keep your home or building protected against the devastating effects of an earthquake.

Shall I still retrofit my home even if I have earthquake insurance?

Don’t you fix your car breaks even though you have car insurance?
Traditionally, if you have a $500.000 house, you are going to pay over $100.000 of damage, while you are saving money for your home insurance. So, if there is a massive seismic activity, your house will be damaged. Meanwhile, the contractors will be overwhelmed with calls, for you are not the only injured after the earthquake.
So, here is the answer to your question: what will you do if your home is not habitable for a while (sometimes for a long while) until you deal with the insurance claim and then find people to fix your home?

Where can we learn more details about earthquake retrofitting?

You can find not only about earthquakes but also plenty of other informative and qualified content on the Army of Builders’ News page, as long as this is a professional retrofit service delivery website - on the Blog section many useful articles are available, which get into more details about retrofitting.

Can basements be retrofitted if it is already finished?

Yes, it can. Army of Builders has trade specialists and skilled carpenters, who will do paneling and siding, also will repair sheetrock and all the other required works, that may be opened up to perform a retrofit.

Earthquake analysis

Seismic analysis is a subdivision of constitutional analysis and as well the calculation of the result of a building or no building structure to seismic activities. It’s a part of the action of earthquake engineering, structural design, or structural assessment and retrofit in areas where earthquakes are prevailing.

Some buildings have the potential to 'wave' back and forth when an earthquake and even severe wind storms happen. This is the fundamental mode, and that’s the lowest density of building response. Most buildings, tho, have higher modes of response, which are particularly activated during earthquakes.