- Page 46 of 46 - News, Notes and Discussion from the Simpson Strong-Tie Engineering Department

Building a Storm Shelter to ICC-500 Design Requirements

According to the National Weather Service, 2011 ranked right up there as one of the worst years on record for tornadoes, having set records for the earliest date of the first tornado, the most states reporting tornadoes, the greatest monthly total, the greatest daily total, and the highest estimated property and crop losses. (Take a look.)

You may wonder: What can I do to protect building occupants (perhaps even my family) in a tornado? It is possible to build your home to higher wind resistance than normally required so that it can resist weak to moderate tornadoes? See my previous blog post, “Designing Light-Frame Wood Structures for Resisting Tornadoes. It Can Be Done!” and also our tornado technical bulletin for more information. But to resist the strongest of tornadoes, the most economical solution is a storm shelter located nearby or in your home. Continue Reading

Ignore Seismic Requirements When Wind Controls?

Prior to joining Simpson Strong-Tie, my career involved the design of projects in California’s San Francisco Bay Area. When designing the primary lateral force resisting system, I would have several pages of seismic base shear calculations and, oh yeah, a one- or two-line calculation of the wind forces – just to show that seismic governed. There was no need for complete wind analysis, since the seismic design and detailing requirements were more restrictive. Of course, building components such as parapets, cladding or roof screens needed a wind design. Unfortunately, when wind appears to control, meeting the seismic requirements is not so simple.

CFS Framed Shear Walls – A Code History

In a previous blog post, I talked about the challenges engineers may face when designing cold-formed steel and some resources available. When designing a building to the current building code, it can be helpful for engineers to understand the history of the different code requirements. This week I will discuss the code development history of CFS framed shear walls.

Prior to the 1997 Uniform Building Code (UBC), there were limited code provisions for design of cold formed steel-framed shear walls. The 1994 UBC had seismic R-factors for light-framed walls, but little else with respect to design or detailing. Code provisions were introduced in the 1997 UBC that included:

So. . .What Do You Love About Structural Engineering?

A few years ago, we hosted a Take Our Daughters and Sons to Work® Day at our home office in Pleasanton, CA. During introductions, several parents told the children what they did and how they chose their particular profession (you can see what my son thinks I do in my bio). At our home office, we have accounting, finance, product management, IT, administration, marketing, and a few others I’m probably missing, so it is a diverse group the kids heard from that day.

And the careers were often not what people had originally planned for. Many shared wonderful stories about the twists and turns their careers took until they finally discovered their passion and job satisfaction. Often, this was a career that they didn’t even know existed when they chose a major in college or first entered the workforce.

So, what was my story?

The Anchorage to Concrete Challenge – How Do You Meet It?

We structural engineers here at Simpson Strong-Tie have a love/hate relationship with anchorage to concrete. Ever since the introduction of the strength design provisions in the 2000 IBC and ACI 318 Appendix D, anchorage to concrete has been a challenge for designers, building officials and manufacturers. SEAONC’s recent testing and the resulting code changes offer some relief to wood-frame designers for sill-plate anchor design at the edge of concrete, but many challenges remain.

With the increasing demand for high-density housing and urban infill projects, designers are now faced with anchoring multi-story wood-framed shear walls to relatively thin elevated concrete slabs (typically referred to as podium slabs). Overturning tension anchorage forces at the ends of shear walls in these projects can routinely be in the 40 kip range and even get as high as 60 kips or more.

Welcome to the Structural Engineering Blog

Welcome to our Structural Engineering Blog! I’m Paul McEntee, Engineering R&D Manager at Simpson Strong-Tie. We’ll cover a variety of structural engineering topics here that I hope interest you and help with your projects and work. Social media is “uncharted territory” for a lot of us (me included!), but we here at Simpson Strong-Tie think this is a good way to connect and even start useful discussions among our peers in a way that’s easy to use and doesn’t take up too much of your time.
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Contest Winners Announced Soon!

Thank you to everyone who subscribed to our new SE Blog! If you subscribed by June 1, you were automatically entered to win one of five Simpson Strong-Tie prize packs. Those of you who also posted a comment to the blog received a bonus entry. We will announce our winners on the blog soon. Good luck!

Official rules for the sweepstakes can be found here.

Code Development: The ASTM Process

I spent a few days last week traveling to attend the Spring ASTM International meetings held in Phoenix, AZ. When I was working as a building designer, I always used ASTM standards in my project specifications or testing and special inspection requirements on a job. But I did not know how these ASTM standards were developed, nor did I know that I could participate in the process.

ASTM standards are voluntary in the sense that ASTM does not require their use. However, since ASTM standards are referenced in building codes and design standards that are adopted by states and local jurisdictions, compliance with those standards is required. So it might be useful for structural engineers to know a little bit about how these standards are created.

But I Don’t Design Cold-Formed Steel…

For the first half-dozen years of my professional career, my experience with cold-formed steel (CFS) consisted of sizing studs for non-structural walls and red-marking the bracing details on architectural plans. When the dotcom bubble burst, my firm needed to shift its focus from high-tech commercial and industrial to more multifamily design work. Several developers we worked with built with CFS, so in addition to designing condominiums instead of cleanrooms, I was designing CFS.

Less than 10% of engineers have any exposure to CFS design as part of their undergraduate education. OK – so this is based on an informal survey of about 50 colleagues, but I suspect if I were to hire a market research firm for lots of money, I’d pretty much get the same response.