Seismic Retrofit Services

Penhall Retrofit Plans for Seismic Retrofit, Soft Story Seismic Retrofit

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 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 do it right.

Seismic Retrofitting Service at Penhalll

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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.

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 it to center core or drill through the bricks vertically and thread rebar or steel through and pour back concrete to secure hole.

Penhall launched operations nearly 60 years ago supporting southern California with a singular commitment to providing the highest level of services to its clients. Since then, Penhall has expanded its reach, scope and expertise, serving clients across the U.S. and beyond. Today, Penhall encompasses 41 strategic locations and employs more than 1,200 professionals, with current and ongoing expansion into Canada. We’ve dedicated that last 60 years to honing our specialized seismic, scanning and concrete services.

Common Soft Story Retrofit Solutions

What are moment frames?

  • A moment frame is a system of columns and beams that are connected to one another with fully and/or partially restrained connections.
  • A special moment frame is expected to withstand significant inelastic deformation as a result of lateral forces. They are used typically in mid/high-seismic regions and are significantly more expensive than other retrofit options.
    INSTALLED SPECIAL MOMENT FRAME AFTER A SEISMIC RETROFIT INSTALLED EXTERNAL SPECIAL MOMENT FRAME ON A NARROW CARPORT

What are cantilever columns?

  • A cantilever is a horizontal beam that is unsupported at its end.
  • A cantilever column is the vertical component that supports the horizontal cantilever beams.
    INSTALLED CANTILEVER COLUMNS AFTER A RETROFIT

What are shear walls?

  • A shear wall is a vertical-oriented wide beam that transfers lateral forces from exterior walls, floors, and roofs to the ground foundation.
    vertical-oriented wide beam also known as a sheer wall

What is destructive testing?

  • Destructive testing is the process of determining design weaknesses.
  • For seismic retrofit projects, the city would like to see the quality and connections of load-bearing beams that are at-risk of failure in the event of an earthquake prior to approving permitting for the project.
  • This type of testing requires exposure of these connections.

ZOOMED IN Destructive testing area to determine design weaknesses. ZOOMED OUT Destructive testing area

What is non-destructive testing?

  • Non-destructive testing is the process of evaluating materials or components for discontinuities or differences in characteristics without causing damage to the structure.
  • Ground penetrating radar uses radio waves to scan concrete.
  • Concrete x-ray uses x-rays or gamma rays to image the interior of a concrete target to identify embedded objects.

Ground penetrating radar being used to locate imbedded hazards GPR Analyst Scanning a concrete slab to locate post tension cable

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Latest News

Rating Buildings for Seismic Resiliency

Recent Recorded California Earthquake

Within the past 24 hours there have been seven earthquakes in Southern California, each of which with a magnitude of 2.2 or below (earthquaketrack.com). Although earthquakes of this magnitude are not even considered “minor” on the Richter scale and are generally not felt, their occurrences and closeness to one another are unsettling nonetheless. The last 30 Days has seen 190 earthquakes in the last thirty days in Southern California, the largest of which actually occurred less than 48 hours ago. Isla Vista experienced a “slight” 4.1 magnitude quake at 9:42 pm, though no reports of damage were reported.  While earthquakes of a relatively small magnitude do not literally “shake” us and therefore may be easy to ignore, it is important to remember that at one point or another, an earthquake of larger magnitude will occur; it is just a matter of when.

For years, there has been extensive discussion about when “the big” earthquake will hit. It has been suggested that Southern California is “overdue” for a big earthquake, which could hit at any time. Although many people would prefer to simply ignore Southern California’s precarious position in relation to the San Andreas Fault. According to the San Andreas Fault website, “the big one”, although “hypothetical”,  is expected to have a magnitude of 8 or greater. Proper steps must be taken to ensure that the negative impacts of this earthquake are as minimal as possible. This is of particular importance in urban areas, due to larger populations and the types of buildings found in these particular places. It is evident that there has been a greater awareness of the threat of these quakes when considering the recent mandatory seismic retrofit ordinances that have been passed in Southern California as well as other areas of California. The recent discourse around the somewhat small but frequent earthquakes that have been occurring, in addition to the imminent threat of a much larger one, has led to a greater understanding the need and importance of seismic retrofitting. The implementation of mandatory seismic retrofit ordinances for possibly vulnerable buildings will benefit and serve thousands of buildings, but most importantly save the lives of those who live in buildings that may be severely impacted by a large and devastating earthquake.

References

http://www.geo.mtu.edu/UPSeis/magnitude.html

http://earthquaketrack.com/v/la/recent

http://www.sanandreasfault.org/BigOne.html

What are the differences between “Ordinary Moment Frames” and “Special Moment Frames”?

Due to the latest seismic ordinances passed in Santa Monica, there has been a lot of talk around different seismic solutions and options, moment frames being one of those options.  There are three different types of moment frames: ordinary, intermediate, and special. After reading this short article, it will only take a moment for you to understand the fundamental differences between Ordinary Moment Frames and Special Moment Frames.

Seismic Retrofit building structure

Ordinary Moment Frame- Seismic Retrofit

 

 

 

 

 

 

To begin, a standard moment frame is defined as a system of columns and beams which are connected by either fully or partially restrained moment connections.  As one might expect based on its name, “ordinary” moment frames, one of the three types of moment frames,  are generally found in areas described as non/low-seismic regions. The expectation is that ordinary moment frames are able to endure limited inelastic deformations caused by lateral forces. Ordinary moment frames only require onsite welding, which differs from the requirements for special moment frames. Special Moment Frames, another type of moment frame, are “special” in that they are expected to endure more significant inelastic deformation than ordinary moment frames. In addition, Special Moment Frames utilize different connections than Ordinary Moment Frames and they do not require field welding. Generally even with on-site welding the cost of Ordinary Moment Frames won’t go over that of a Special Moment Frame. These connections must be prequalified, as stipulated by the American Institute of Steel Construction.  Since Special Moment Frames can endure more deformation, they are often found in areas described as mid to high-seismic regions. Seismic retrofits constructed utilizing moment frames can sometimes be more costly and time consuming because moment frames often require more welding on site than other frames do. Traditionally, special moment frames are more expensive than ordinary moment frames because these types of frames are often found in mid/high-seismic regions. Your engineer may decide whether or not moment frames are right for your particular project but they are preferred under certain circumstances. If your building includes large open areas within your structure, such as a tuck-under parking garage, moment frames would often be the building solution that is preferred.  Considering the latest ordinances regarding soft story seismic retrofits, the Santa Monica area will be seeing moment frames of all types over the course of the next five years.

Seismic Retrofit Structure to decrease earthquake damage

Photo courtesy of Hardy Frame by MiTek

For more helpful information on seismic retrofit services that will fit your individual projects needs, keep an eye out for more blog postings on our website- www.penhall.com/seismic-retrofit/ 

References inlcude: http://csengineermag.com/article/steel-moment-frames-101-what-to-consider-when-creating-wide-open-spaces/ (by Dylan Richard and Walter Moore) 

Seismic Retrofit Service in Santa Monica – Industry News

In Santa Monica, many property owners had retrofits completed in 1994 after the Northridge quake. However, many of those retrofits were only partially completed, i.e. parapet only, diaphragm anchorage, full or partial wall bracing, etc. It is at the discretion of the owner to what level of resiliency they desire for their building. At minimum, the seismic retrofit ordinances aim to make buildings safe enough for tenants to exit the building safely in the event of a large earthquake. This does not guarantee that the building will be habitable after an earthquake. The seismic retrofit notice that owners will receive would inform them of the additional work that needs to be done to be up to code. For other buildings that would in fact need to be in operation after a large quake, i.e. hospitals, these buildings must be kept to a higher standard of resiliency.

One such rating system for evaluating how well a building will hold up in an earthquake is known as the United States Resiliency Council Building Rating System. Per the USRC website, “The USRC Building Rating System assigns one to five stars for three performance measures – Safety, Damage expressed as repair cost, and Recovery expressed as time to regain basic function.”

Every city should be concerned first and foremost about the safety of its residents, but secondly, they should want to make sure that the City would still be able to thrive after an earthquake. Would the residents be able to return to their homes and/or jobs after a quake, or will they move to an area of less seismic activity? Per www.fema.gov/building-codes, “If you live or work in retrofitted structures, you’re less likely to be injured during an earthquake. After the earthquake, you’re also more likely to have a home and a job to which you can quickly return. Businesses that use retrofitted buildings are more likely to survive damaging earthquakes and to sustain shorter business interruptions and fewer inventory losses.”

May 18, 2017

A successful 2nd Annual Los Angeles Seismic Retrofit Fair for the community

Penhall Company proud to exhibit at the 2nd annual Los Angeles Seismic Retrofit Fair

The bustle of the room grew louder as local property owners from Los Angeles started to arrive at the 2nd Annual Los Angeles Seismic Retrofit Fair. The tables were a buzz as vendors engaged with the locals.

The fair that took place April 17th, 2017 in Los Angeles and was designed to have all the information and vendors in one place for seismic retrofitting.  In the eyes of the community it seemed it was a success.

Penhall Company Seismic Retrofit Services was proud to be present to discuss retrofit needs one on one with customers.  The energy in the room was good, while not all owners were thrilled about the mandatory ordinance most seemed to be positive.  In the end it seems a lot of folks just want the city safer in the event of a major earthquake and this event helped people get closer to their goal of compliance.

Penhall Company Booth ready for the LA Retrofit Fair

In talking with the public yesterday it is clear that property owners are much more interested in Design+Build firms.  The idea of being a “middle man” between and engineer and contractor is not appealing to many.  Other property owners expressed a deep interest in knowing their contractor is honest and reliable.  With so many soft-story retrofits that need to be done in the city some owners were concerned with choosing the right contractor for fear of a bad experience.  We at Penhall Company always try to encourage customers to do their research, get 3 quotes, consult with an engineer and think about their vendor choice before signing a contract. Following your gut can take you far. If something doesn’t feel right, move on to another vendor better suited to your needs.

Penhall was proud to sit and speak with each potential customer about their concerns and retrofits including timelines, costs and tenant support. Our 60 years servicing the local community is a testament to our commitment to high quality and fair priced engineering services.

Read more about the Seismic Retrofit Work Program

Flyer for the 2nd Annual Los Angeles Seismic Retrofit Fair.

April 18, 2017

Building Resiliency Rating System

When evaluating levels of seismic retrofitting, it is at the discretion of the owner to what level of resiliency they desire for their building. At minimum, the seismic retrofit ordinances aim to make buildings safe enough for tenants to exit the building safely in the event of a large earthquake. This does not guarantee that the building will be habitable after an earthquake. For other buildings that would in fact need to be in operation after a large quake, i.e. hospitals, these buildings must be kept to a higher standard of resiliency.

From Los Angeles Mayor Garcetti’s “Resilience by Design” report, “Our building code is designed around a life-safety requirement that mandates construction that ensures a low probability of collapse in the worst earthquake. The code is not designed, however, to make it so buildings, while still standing, are also likely to remain usable after an earthquake. This report recommends a voluntary rating system to encourage building owners to invest in the resilience of their buildings so that they not only stay standing after an earthquake, but so that they also remain functional.”

One such rating system for evaluating how well a building will hold up in an earthquake is known as the United States Resiliency Council Building Rating System. Per the USRC website, “The USRC Building Rating System assigns one to five stars for three performance measures – Safety, Damage expressed as repair cost, and Recovery expressed as time to regain basic function.”

Every city should be concerned first and foremost about the safety of its residents, but secondly, they should want to make sure that the City would still be able to thrive after an earthquake. Would the residents be able to return to their homes and/or jobs after a quake, or will they move to an area of less seismic activity? Per www.fema.gov/building-codes, “If you live or work in retrofitted structures, you’re less likely to be injured during an earthquake. After the earthquake, you’re also more likely to have a home and a job to which you can quickly return. Businesses that use retrofitted buildings are more likely to survive damaging earthquakes and to sustain shorter business interruptions and fewer inventory losses.”

April 14, 2017