- Page 48 of 49 - News, Notes and Discussion from the Simpson Strong-Tie Engineering Department

Top 3 Roof Deck Design Considerations for High Wind Events

Was it JFK who said, “The time to repair the roof is when the sun is shining?” He was likely using the roof as an analogy for the economy, but I take things literally and wanted to talk about roofs. The time to think about the design of your roof and its function in a high wind event like a hurricane or tornado is right now.

During a high wind event, a roof deck is expected to perform many functions. It should prevent water intrusion from rain, withstand impacts and protect those inside from hail. It also needs to act as a diaphragm – transferring lateral loads to shear walls and resisting the vacuum effects of wind uplift forces.Continue Reading

Flexible or Rigid? Multi-Story Light-Frame Structure Design Considerations

I like to think I’m flexible, but I’ve been accused of being rigid at times. I guess that’s what therapy is for. If you were to ask a light-frame structure diaphragm that same question, you would likely get multiple conflicting answers. The 1988 UBC first introduced parameters to evaluate diaphragm rigidity. Earthquake Regulations Section 2312(e)6 stated:

Figure 1. Flexible Diaphragm Definition from ASCE 7-05

Provision shall be made for the increased shears resulting from horizontal torsion where diaphragms are not flexible. Diaphragms shall be considered flexible for the purposes of this paragraph when the maximum lateral deformation of the diaphragm is more than two times the average story drift of the associated story. This may be determined by comparing the computed midpoint in-plane deflection of the diaphragm under lateral load with the story drift of adjoining vertical resisting elements under equivalent tributary lateral load.

Vacation – Can Engineers Take It?

My blog post is late this week – I’m going to blame it on vacation. According to this article analyzing a study by Expedia, Americans did not use $34 billion worth of vacation time they were entitled to in 2011. This started me thinking about how difficult it can be for structural engineers to take a real vacation.Continue Reading

Congratulations to Our Structural Engineering Blog Sweepstakes Winners!

To launch our Structural Engineering Blog, in April we hosted a sweepstakes inviting you to sign up for blog email updates by June 1, 2012. Everyone who also posted a comment to the blog during that time period received a bonus entry into the sweepstakes. The five winning entries received a Simpson Strong-Tie prize pack. Congratulations to our winners:

Daniel Weinstein, VP of The Kachele Group, Inc. wears his Simpson Strong-Tie t-shirt from the prize pack.

R. Johnson – Chicago, Illinois

D. Bentti – Anchorage, Alaska

R. Porter – Westfield, MA

D. Weinstein, PE – Philadelphia, PA

Z. Andriuk – White Plains, MD

If you’d like automatic email updates when a new blog entry is posted (usually once a week), sign up here.

What are your thoughts? Visit the blog and leave a comment!

Do 50 Kip Wood Construction Connectors Exist?

The 2009 IBC Section 1604.4 states, “Load effects on structural members and their connections shall be determined by methods of structural analysis that take into account equilibrium, general stability, geometric compatibility and both short and long-term material properties.” This requirement applies to a 200 pound handrail connection as well as a 50,000 pound glulam connection.Continue Reading

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?

Simpson Strong-Tie Research: The Tye Gilb Lab

I often get asked about Simpson Strong-Tie R&D projects. Since I can’t always talk about what new products we are working on, I thought I’d give you a sneak peek into where the magic happens. The Tye Gilb Research Laboratory is our R&D hub. Built in 2003 in Stockton, CA, the lab is named in memory of Tyrell (Tye) Gilb, a former professor of architecture and a wonderful man, who led our company’s research and development efforts for 35 years.