Simpson Strong-Tie recently had the opportunity to work with MAK Construction to come up with a rather unique solution for a residential project in Phoenix, Arizona. Our Strong Frame® Moment Frame Selector software was used by the engineer on record, L.R. Nelson Consulting Engineers, LLC, to design this truly “special” special moment frame (SMF). The challenge for this particular moment frame design was figuring out how to work around a large garage door opening on the bottom floor without obstructing the window openings on the next floor, because the standard SMF design would cause the beam to cross right through the middle of the windows as they were situated. The solution required dropping the beam below the top of the columns, something seldom seen in moment frame designs. However, our engineering services, in collaboration with L.R. Nelson Consulting Engineers, were able to determine that dropping the beam to the needed level would be quite feasible in this case, and within 24 hours a new design was sent to the EOR and to the contractor for final approvals, which were granted.
In this post, we follow up on our May 2 webinar, Seismic Resilience and Risk Assessment of the Yield-Link® Connection for Steel Construction, by answering some of the interesting questions raised by the attendees.
During the webinar, we discussed how to achieve seismic resiliency in steel construction with our Yield-Link connection for steel special moment frames and the Seismic Performance Prediction Program (SP3) by Haselton Baker Risk Group. In case you weren’t able to join our discussion, you can watch the on-demand webinar and earn PDHs and CEUs here.
As with our previous webinars, we ended with a Q&A session for the attendees. Jeff Ellis, our Director of Codes and Compliance, and Curt Haselton and Jared Debock, from Haselton Baker Risk Group, answered as many questions as they could in the time allowed. Now we are back to recap some of the more commonly asked questions and their answers. If you’re interested in seeing the full list of questions, click here.
Last year, I gave a presentation at the annual National Council of Structural Engineers Associations (NCSEA) Summit in Orlando, Florida, titled “Becoming a Trusted Advisor: Communication and Selling Skills for Structural Engineers.” As this was a summit for the leaders of the structural engineers associations from across the country, I wasn’t sure how many people would find it valuable to spend their time learning about a very nontechnical topic. To my surprise and delight, the seminar ended up being standing-room only, and I was able to field some great questions from the audience about how they could improve their selling and communication skills. In the many conversations I had with the conference attendees after my presentation, the common theme was that engineers felt they needed more soft-skills training in order to better serve their clients. The problem, however, was finding the time to do so when faced with the daily grind of design work.
When I started my first job as a design engineer at a structural engineering consulting firm straight out of school, I was very focused on improving and expanding my technical expertise. Whenever possible, I would attend building-code seminars, design reviews and new product solution presentations, all in an effort to learn more about structural engineering. What I found as I progressed through my career, however, was that no matter how much I learned or how hardworking I was, it didn’t really matter if I couldn’t successfully convey my knowledge or ideas to the person who really mattered most: the client.
How can an engineer be most effective in explaining a proposed action or solution to a client? You have to be able to effectively sell your idea by understanding the needs of your client as well as any reasons for hesitation. The importance of effective communication and persuasion is probably intuitive to anyone who’s been on the sales side of the business, but not something that occurs naturally to data-driven folks like engineers. As a result of recent legislation in California, however, structural engineers are starting to be inundated with questions from a group of folks who have suddenly found themselves responsible for seismically upgrading their properties: apartment building owners in San Francisco and Los Angeles.
Imagine for a moment that you are a building owner who has received a soft-story retrofit notice under the City of Los Angeles’ Ordinance 183893; you have zero knowledge of structural engineering or what this term “soft-story” even means. Who will be your trusted advisor to help you sort it out? The City of Los Angeles Department of Building and Safety (LADBS) has put together a helpful mandatory ordinance website that explains the programs and also offers an FAQ for building owners that lets them know the first step in the process: hire an engineer or architect licensed in the state of California to evaluate the building.
I’ve had the opportunity to be the first point of contact for a building owner after they received a mandatory notice, because it turns out some relatives own an apartment building with soft-story tuck-under parking. Panicked by the notice, they called me looking to understand why they were being forced to retrofit a building that “never had any problems in the past.” They were worried they would lose rent money due to tenants needing to relocate, worried about how to meet the requirements of the ordinance and, most importantly, worried about how much it was going to cost them. What they really wanted was a simple, straightforward answer to their questions, and I did my best to explain the necessity behind retrofitting these vulnerable buildings and give an estimated time frame and cost that I had learned from attending the first Los Angeles Retrofit Resource Fair in April 2016. With close to 18,000 buildings in the cities of San Francisco and Los Angeles alone that have been classified as “soft-story,” this equates to quite a number of building owners who will have similar questions and be searching for answers.
To help provide an additional resource, Simpson Strong-Tie will be hosting a webinar for building owners in the Los Angeles area who have received a mandatory soft-story retrofit notice. Jeff Ellis and I will be covering “5 Steps to a Successful Retrofit” and helping to set a clear project path for building owners. The five steps that Simpson Strong-Tie will be recommending are:
- Understanding the Seismic Retrofit Mandate
- Partnering with Design Professionals
- Submitting Building Plans with the Right Retrofit Product Solutions
- Communicating with Your Building Tenants
- Completing Your Soft-Story Retrofit
We encourage you to invite any clients or potential clients to attend this informative webinar, which will lay the foundation for great communication between the two of you. As part of the webinar, we will be asking the building owners for their comments, questions and feedback so we can better understand what information they need to make informed decisions, and we will be sure to share these with the structural engineering community in a future post. By working together to support better communication and understanding among all stakeholders in retrofit projects, we will be well on our way to creating stronger and more resilient communities!
For additional information or articles of interest, there are several resources available:
- Register for the “5 Steps to a Successful Retrofit” webinar on April 26
- Register to attend the 2nd Los Angeles Seismic Retrofit Resource Fair on April 17 (and stop by the Simpson Strong-Tie booth!)
- Find a structural engineer through the Structural Engineers Association of Southern California (SEAOSC)
- Resilience by Design: City of Los Angeles Lays Out A Seismic Safety Plan
- City of San Francisco Implements Soft-Story Retrofit Ordinance
- Soft-Story Retrofits Using the New Simpson Strong-Tie Retrofit Design Guide
- Visit the Simpson Strong-TieSoft-Story Retrofit Center
- The Los Angeles Times Soft-Story Map
The Great ShakeOut Earthquake Drill is an annual opportunity for people in homes, schools and organizations to practice what to do during earthquakes and improve their preparedness. In a post I wrote last October about the Great ShakeOut, I reminisced about the first earthquake I had to stop, drop and cover for – the Livermore earthquake in January, 1980. This year got me thinking about how our evacuation drills work.
At Simpson Strong-Tie, we use the annual Great ShakeOut drill to practice our building evacuation procedures. Evacuation drills are simple in concept – alarms go off and you exit the building. We have volunteer safety wardens in different departments who confirm that everyone actually leaves their offices. There are always a few people who want to stay inside and finish up a blog post. Once the building is empty and we have all met up in the designated meeting area, we do a roll call and wait for the all-clear to get back to work.
Several years ago the alarms went off. While waiting for the drill to end, we were concerned to see fire fighters arrive and rush into the building. Realizing this was not a drill, there were some tense moments of waiting. The fire chief and our president eventually walked out of the building and our president was yelling for one of our engineers. Turns out the engineer (who shall remain nameless) was cooking a chicken for lunch. Yes, a whole chicken. The chicken didn’t make it – I’m not sure what the guilty engineer had for lunch afterwards. At least we received extra evacuation practice that year. We aren’t allowed to cook whole chickens in the kitchen anymore.
Simpson Strong-Tie is helping increase awareness about earthquake safety and encouraging our customers to participate in the Great ShakeOut, which takes place next Thursday on October 20. It’s the largest earthquake drill in the world. More than 43 million people around the world have already registered on the site.
On October 20, from noon to 2:00 p.m. (PST), earthquake preparedness experts from the Washington Emergency Management Division and FEMA will join scientists with the Washington Department of Natural Resources and the Pacific Northwest Seismic Network for a Reddit Ask Me Anything – an online Q&A. Our very own Emory Montague will be answering questions. The public is invited to ask questions here. (Just remember that this thread opens the day before the event and not sooner.)
Earthquake risk is not just a California issue. According to the USGS, structures in 42 of 50 states are at risk for seismic damage. As many of you know, we have done a considerable amount of earthquake research, and are committed to helping our customers build safer, stronger homes and buildings. We continue to conduct extensive testing at our state-of-the-art Tye Gilb lab in Stockton, California. We have also worked with the City of San Francisco to offer education and retrofit solutions to address their mandatory soft-story building retrofit ordinance and have created a section on our website to give building owners and engineers information to help them meet the requirements of the ordinance.
Last year, Tim Kaucher, our Southwestern regional Engineering Manager, wrote about the City of Los Angeles’s Seismic Safety Plan in this post. Since that time, the City of Los Angeles has put that plan into action by adopting mandatory retrofit ordinances for both soft-story buildings and non-ductile concrete buildings. Fortunately, California has not had a damaging earthquake for some time now. As a structural engineer, I find it encouraging to see government policy makers resist complacency and enact laws to promote public safety.
Participating in the Great ShakeOut Earthquake Drill is a small thing we can all do to make ourselves more prepared for an earthquake. If your office hasn’t signed up for the Great ShakeOut Earthquake Drill, we encourage you to visit shakeout.org and do so now.
“From a seismological standpoint, Northridge was not a big earthquake.” This is first sentence of the “Resilience by Design” report by L.A. Mayor’s Seismic Safety Task Force led by Dr. Lucy Jones of the U.S. Geological Survey (USGS). The report is the culmination of a year-long investigation into the greatest vulnerabilities of the city from a major seismological event. Continue Reading
I have a special place in my heart for old buildings. Every college design course I took was related to new design. Concrete, steel, or wood design, the design problem was invariably part of a new building. I thought structural engineers designed new buildings. When I showed up for my first day of work wearing dress pants, a button-down shirt and a tie, I was handed a flashlight, tape measure, a clipboard and a Thomas Guide map (no Google maps back then) and sent to do as-built drawings for a concrete tilt-up that we were retrofitting.
When I was designing buildings, I created a lot of as-built drawings. Figuring out how a building was put together, what the structural system was (or wasn’t!) and designing a lateral load path in these old, and often historic buildings, was immensely satisfying. Knowing that history, it should not be surprising I have done a number of blog posts related to seismic retrofits. Soft-Story Retrofits, San Francisco’s Soft-Story Retrofit Ordinance, Remembering Loma Prieta, Resilient Communities, FEMA P-807, and Home Seismic Retrofit (there are probably a couple I forgot).
This week, Los Angeles Mayor Eric Garcetti proposed new seismic safety regulations . The recommendations are to retrofit soft-story wood-framed buildings within five years and older concrete buildings within 30 years. While these are only recommendations, it is encouraging to see politicians supporting policies to promote resiliency and life safety.
In San Francisco, thousands of building owners are already required by law to seismically retrofit multi-unit (at least five) soft-story, wood-frame residential structures that have two or more stories over a “soft” or “weak” story. These buildings typically have parking or commercial space on the ground floor with two or more stories above. As a result, the first floor has far more open areas of the wall than it actually has sheathed areas, making it particularly vulnerable to collapse in an earthquake.
San Francisco’s ordinance affects buildings permitted for construction before Jan. 1, 1978. Mandatory seismic retrofit program notices requiring that buildings be screened were sent out in September, 2013, to more than 6,000 property owners. It is anticipated that approximately 4,000 of those buildings will be required to be retrofitted by 2020.
“When we look at the demographic of these buildings, they house approximately 110,000 San Franciscans. It’s paramount that we have housing for people after a disaster. We know we will see issues in all types of buildings, but this is an opportunity for us to be able to retrofit these buildings while keeping an estimated 1100,000 San Franciscans in their homes and, by the way of retrofit, allowing them to shelter in place after a disaster,” according to Patrick Otellini, San Francisco’s chief resilience officer and director of the city’s Earthquake Safety Implementation Program. “This exponentially kick starts the city’s recovery process.”
One solution to strengthen such buildings is the Simpson Strong-Tie® Strong Frame® special moment frame. Its patented Yield-Link™ structural fuses are designed to bear the brunt of lateral forces during an earthquake, isolating damage within the frame and keeping the structural integrity of the beams and columns intact.
“The structural fuses connect the beams to the columns. These fuses are designed to stretch and yield when the beam twists against the column, rather than the beam itself, and because of this the beams can be designed without bracing. This allows the Strong Frame to become a part of the wood building and perform in the way it’s supposed to,” said Steve Pryor, S.E., International Director of Building Systems at Simpson Strong-Tie. “It’s also the only commercially-available frame that bolts together and has the type of ductile capacity that can work inside of a wood-frame building.”
Another key advantage of the Simpson Strong-Tie special moment frame is no field welding is required, which eliminates the risk of fire in San Francisco’s older wood-framed buildings.
To learn more about San Francisco’s retrofit ordinance, watch a new video posted on strongtie.com/softstory. For more information about the Strong Frame special moment frame, visit strongtie.com/strongframe.
Launched in January 2013, the Simpson Strong-Tie® Strong Frame® special moment frame (SMF) has been successfully used on many projects around the country. We’ve explored several aspects of the frame in previous blog posts, including beam bracing requirements, soft story retrofits, and the San Francisco retrofit ordinance. If you have specified the Strong Frame SMF on your project, here are a few helpful items to review during your structural observations at installation.
When the special moment frame is ordered, Simpson Strong-Tie sends the contractor a frame verification sheet to verify the dimensions (Figure 1). It is not uncommon for minor adjustments to be made to accommodate specific field conditions. We recommend the framer follow up with the Designer to ensure the needed modifications do not alter the design of the frame based on deflection or strength stand point limitation(s). Once we receive the signed verification, we begin fabricating the frame. The accompanying concrete anchors are usually shipped before the frame so they can be placed ahead of time.
It all starts with the concrete! The majority of misinstallation issues involve anchorage placement. Anchors not placed correctly can alter the frame that’s already been ordered, affecting lead times or requiring retrofit to properly transfer the frame forces into the concrete. Contact your local Simpson Strong-Tie sales rep to help with any questions.
Placement of the Moment Frame Shear Lug (MFSL) is critical to ensure proper transfer of shear forces into the foundation. If you are visiting the jobsite prior to concrete placement, take a look at the orientation of the MFSL. The MFSL contains back-to-back structural angles placed at the top of concrete to transfer the shear component of the Strong Frame SMF forces into the concrete. Figure 2 shows the proper placement of the MFSL and template in relationship to the direction of the column.
The template has a similar appearance to the shape and size of the column base plate, which sometimes leads to the tendency to orient the template 90 degrees from its proper installation, as shown in Figure 3. The template has two half circles at the center of the anchor bolts for proper measurement (center-to-center of columns) by the contractor, as shown in Figure 4.
The templates are temporary and intended to be removed prior to frame installation (unlike the case in Figure 3). So placement of the shear lugs is more critical to verify than the direction of the template, since the contractor may remove the template and reinstall it in an alternate orientation. The vertical legs of the two structural angles should intersect the column’s weak axis (perpendicular to center of frame) as shown in Figure 5, and should not be placed parallel to the strong axis.
According to ASTM A325, installation requires 11 bolts snug tight at each beam-column connection (labeled “a” in Figure 6), and the column needs to be attached to the four anchor bolts into the base of each column. Many components of the Strong Frame SMF are factory-installed, including the Yield-LinkTM structural fuses, Buckling Restraint Plates (BRP), and nailers. The Yield-Link fuses and BRP should not be disassembled. Figure 6 illustrates an instance where the BRP was loosened during erection. The BRP prevents the Yield-Link fuses from buckling when the frame is subjected to compression forces. Contact Simpson Strong-Tie if you encounter this in the field.
The wood nailers may be replaced in kind. It is important to note that attachment of the nailers may not utilize all available bolt holes on the column and beam. Various holes are left unused for flexibility with installation of utilities and electrical wiring.
Lastly, often overlooked at installation are the required SDS screws through the column cap plate into the framing above (Figure 7). The SDS screws are included with the installation kit. They are required for bracing of the column on both faces of the column.
How is the Strong Frame special moment frame working for you? Please let us know in the comments!
NOVA, the highest rated science series on television, recently aired a segment on the Colorado State University-led NEES-Soft project that tested Simpson Strong-Tie® Strong Frame® special moment frames as a seismic retrofit solution for soft-story buildings. Simpson Strong-Tie and our special moment frame were prominently featured in the clip. You can watch the entire “Making Stuff Safer” episode on PBS here.
Today the NEES-Soft project has begun testing the steel Simpson Strong-Tie® Strong Frame® Special Moment Frame as a retrofit option for soft-story buildings at the NEES outdoor shake table facility at UC San Diego. The testing is focused on validating the FEMA P-807 design procedure, which attempts to create a least-cost retrofit solution by only retrofitting the garage areas of problem buildings.Continue Reading
Unreinforced masonry (URM) buildings in moderate- to high-seismic areas can be a disaster in waiting. These types of structures have very little of the ductility required of structures to prevent loss of life or business disruption in a seismic event. (Consult our Structural Engineering Blog post “Building Drift – Do You Check It?” for a discussion on ductility.) Many of these buildings are in densely populated areas, have historical meaning, provide important living or business spaces, and can be costly to retrofit. In this blog, Simpson Strong-Tie engineers discuss tools available for engineers to assess these buildings and design the retrofits needed to mitigate a potential loss of life and increase seismic resiliency.