Seismic Retrofitting Archives - Sheedy Crane


September 13, 2019by elite0

Earthquakes in California

We’ve experienced our fair share of earthquakes and thus realize the importance of seismic retrofitting. Like Florida to hurricanes, earthquakes are a fact of life in California. If you’re a native Californian or have lived in California long enough, you’ll have experienced at the very least a few tremors from time to time. As you may know, Sheedy Drayage Co is headquartered in sunny San Francisco and we have decades of experience going back to 1925, operating in the Bay Area.

 If you the only thing you remember from your high school geology class is falling asleep, here’s a quick recap: California rests on what is called the San Andreas fault—which is a huge fault that runs for about 800 miles. When the Pacific and North American plates begin to move, it creates what we know as earthquakes, and many of them occur near fault lines which were originally created by seismic activity.

What is Seismic Retrofitting?

We’ve established that earthquakes happen in California and they’re going to continue happening. The real question is what can be done about them? The chief concern is that older buildings are much more susceptible to the lateral forces that earthquakes create. Thankfully, skilled laborers can make retrofitting possible. Retrofitting is exactly as it sounds, you take an old structure and add new technologies to it that can increase the building’s durability and longevity.

In the case of California, many important and historic buildings serve to benefit greatly from seismic retrofitting. The procedure not only confers existing structures with more resistance against earthquakes and other seismic activity,  Consider that many buildings exist that are more than 20 years old, the building codes have changed considerably since then and are not only more stringent in terms of materials but include many safety requirements as our understanding of civil engineering and social needs change.

Sheedy Crane Seismic Retrofit Projects

Sheedy Drayage Co has done many successful retrofits on numerous key buildings in California in the past few decades—the most major being the retrofitting of San Francisco’s City Hall, which is the largest structure in the world to be upgraded with seismic base isolators. We’ve had several major retrofitting projects in California for many major City Hall’s such as Pasadena, Oakland, and the aforementioned San Francisco City Hall. The seismic retrofitting work Sheedy has done to the Benicia-Martinez Bridge involved 22 friction-pendulum isolators installed tolerate loads in excess of 3,500 tons—the largest of its time. Many of the concepts involving columnal load transfer and seismic dampening are unique to Sheedy, including a specially designed friction gripping technique.

Seismic Retrofitting Services in the San Francisco Bay Area

Sheedy Drayage Co has been operating out of the Bay Area of San Francisco since the 1920s. We are one of the leading contractors of crane, heavy hauling, and rigging services in California! Our expertise in these domains has contributed to our continued success over the past few decades.

We employ a staff of highly experienced engineers that are experts in designing solutions that ensure the proper execution of all hauls, crane lifts, and any retrofitting needs through the use of the latest modeling techniques in CAD software.

If you have a project that requires these services, you can contact your office of choice here!


April 1, 2019by elite0

Each year, southern California experiences an estimated 10,000 earthquakes. The majority of earthquakes are so small that they are never felt on the surface and only several hundred of these are greater than a magnitude of 3.0. About 15-20 of these earthquakes reach a magnitude of 4.0. Generally, the aftershock of a large earthquake can produce a number of earthquakes of varying magnitudes for many months after the initial earthquake.

Due to the amount of earthquakes in California, seismic base isolation has become a relatively new retrofitting technique that helps provide a structure more flexibility to withstand the lateral forces of an earthquake. Base isolators act like large “motor mounts” when placed under a load-bearing column of a bridge or building and, during a seismic event, the isolators absorb the impact which reduces the seismic forces transmitted through the building. Seismic upgrades are a necessary repair to old, historical structures. Often times, the technology to protect against seismic events simply did not exist when the historical structure was built.

construction site

Seismic Retrofitting

The process of seismic retrofitting strengthens weak connections found in roof to wall connections, shear walls, roof diaphragms, and continuity ties in existing buildings. Building codes were much less stringent until 1998, when past structural codes and requirements were updated to support the safety of the occupants and integrity of the structure.

Reasons for Seismic Retrofitting

The process of seismic retrofitting is performed for a number of reasons; the key motive is to ensure the structural security of a building’s machinery, inventory, and employees.

  • Improve the marketability of a building.

The probable maximum loss (PML) of a building is determined using a number of factors when buyers are looking at real estate. Structural integrity of a building is greatly improved when the base of a building is stabilized using seismic retrofitting. Buyers are more inclined to buy a property that will provide more security and less liability to themselves and their tenants. The number of lenders will increase when your building is safe, which will result in more buyers of the property.

  • Reduced potential for legal litigation and injury

In the event of a building collapse, an owner can lose a significant amount of money if it can be proven – through litigation – that a building was in need of structural repair and they did nothing to remedy the situation. Insurance coverage means nothing against a successful negligence litigation. Seismic retrofitting ensures that a property owner will not be held liable for negligence, making the purchase of said real estate an attractive choice.

  • Increased Safety of the Tenants

Who wants to live or operate a business in a building that has not been proven to be structurally sound? A building upgraded with seismic retrofitting results in tenants staying for longer periods of time due to peace of mind and an increased sense of security.

  • Insurance Companies

Rates for insurance claims regarding earthquakes have increased 3-to-6-fold since 2005. In the future, many insurance companies may not write coverage for earthquakes if the owner did not take all the proper steps to ensure the structural integrity of the building.

Seismic Retrofitting San Francisco Bay Area

Sheedy Crane has been an instrumental player on a number of key retrofit projects across California. Some of our projects include San Francisco’s City Hall, Pasadena City Hall, Oakland City Hall, the Veterans Administration Medical Center in Long Beach, and the Martin Luther King Civic center, to name a few. Get loans from money fall for your financial needs.  A complete list of our work can be found on our seismic retrofitting page. We can help complete column base isolator, slider, and flat-jack installation services, as well as column isolation, temporary support, jacking system installation, and load transfer engineering. We offer complete project management and engineering services performed directly by our very own Sheedy Drayage Co. personnel. If you would like to get in touch about a possible project, visit our contact page and reach out!