Penhall Company

Penhall_Seismic Retrofit



About us

Penhall is your top choice for seismic engineering and construction services for every type of seismic retrofitting. Penhall Company is celebrating 60 years of excellent service! Whatever your design build need we are ready to assist you with your next seismic retrofitting project.

Penhall has a long history of seismic work. While we possess the resources and capabilities to take on any size contract, we consider no job too specialized, too large or too small. We believe that every project deserves our utmost attention to detail and commitment to client satisfaction. Our clients know they can depend on us to get the job done on time and on target, from start to finish and every step in between. Whatever your needs, wherever you’re located, trust Penhall Seismic retrofit services to do it right.

An example Penhall seismic retrofit of a soft story building in Los Angeles. (Photo courtesy of Penhall Company)


Buildings at Risk from Seismic Events

Soft Story

Currently in California the most common type of seismic retrofitting is called soft-story retrofit. The weak wood frames are often seen in multifamily apartment dwellings with tuck under parking. This style of building is a common design in both San Francisco and Los Angeles. Due to multiple seismic retrofit ordinances in the State of California cities like San Francisco and Los Angeles have already begun engineering and construction to become compliant. Other cities are following suit like Santa Monica and West Hollywood. We expect many more cities to jump in line to become compliant with new seismic safety standards. Common solutions for soft-story retrofitting are steel special moment frames, cantilevered column solutions, or shear wall paneling.

An example of a soft story building in San Francisco. (Photo from: Flickr)


Non-Ductile Concrete

Another type of seismic retrofitting includes non-ductile concrete buildings. Often seen in multi-story buildings built pre 1978 before seismic codes were tightened. The buildings are considered reinforced concrete in design, but often don’t have enough steel reinforcement to handle a major seismic event. While there are several combinations of solutions for non-ductile concrete steel beam installations and polymer fiber wrap solutions are often used to retrofit non-ductile concrete buildings.

Unreinforced Masonry (URM)

URM construction is another type of seismic retrofit that Santa Monica is most recently preparing for. This type of construction often seen on older historic buildings has no metal or steel reinforcements at all and is literally often only brick and mortar. A common solution is to center core or drill through the bricks vertically and thread rebar or steel through and pour back concrete to secure the hole.


FRP Installation

Penhall Company Seismic Retrofit Services department is proud to be a certified applicator of advanced composite materials, often referred to as fiber reinforced polymer (FRP) or “fiberwrap”.

This material is used to strengthen structures in the same way that steel would, but an added benefit is that these composite materials add significantly less weight.

FRP systems can be used to strengthen reinforced concrete and unreinforced masonry walls, if deemed the best solution for your building’s retrofit needs.

This strengthening solution has been utilized in thousands of retrofit and strengthening projects and has proved to perform very well in the event of earthquakes.

For more information on FRP systems, call us today to speak to one of our certified applicators.


Our service locations

Los Angeles

As seen posted by the LADBS, the City of Los Angeles passed Ordinance 183893, which requires the retrofit of pre-1978 wood-frame soft-story buildings and non-ductile concrete buildings. The goal of the mandatory seismic retrofit ordinance is to reduce these structural shortfalls and improve the safety of the flagged buildings during earthquakes in Southern California. Deprived of retrofitting, the weak buildings may be exposed to major structural damage.

San Francisco

In accordance with the Mandatory Seismic Retrofit Program (MSSP), San Francisco requires the retrofit of pre-1978 wood-frame soft-story buildings which have not been previously seismically strengthened. The goal of the program is to ensure the safety and continuance of San Francisco’s housing to create a more resilient city. Deprived of retrofitting, the weak buildings may be exposed to major structural damage and possible collapse.

Santa Monica

Santa Monica is one of the latest cities in California to require seismic retrofitting of vulnerable buildings. With 60 years of excellent service in the construction industry, Penhall is adequately positioned to meet your needs. We have a division focused on seismic retrofitting in California, and have a dedicated team to guide our clients throughout the entire retrofit process.

West Hollywood

West Hollywood is one of the latest cities in California to get the ball rolling on seismic compliance ordinances. A City Council meeting took place on April 3rd, 2017 to discuss the seismic ordinance. An advisory group concluded that approximately 780 soft-story buildings would need to be retrofitted. City officials are extending their implementation of their ordinance for another year to step through more details and come to a final agreement on unresolved concerns.


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Los Angeles Area



Phone: (213) 358-2514


San Francisco Area



Phone: (415) 619-3204


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