Note: Answers are based on ASCE 7-16, Minimum Design Loads for Buildings and Other Structures.
For diaphragm design, when do I apply overstrength (Ωo) load combinations and when do I apply the 25% increase on my diaphragm forces? …
What are they, really, and what do they entail?
Structural engineering consulting firms are occasionally hired to review a design performed by another engineering firm. The review is frequently a traditional pre-construction structural peer review performed to achieve a better project outcome. The practice of having a traditional peer review performed is becoming more commonplace for Risk Category III and IV buildings, which include tall buildings, buildings with large occupant loads, and essential structures. Peer review is also commonplace for structures designed using performance-based procedures or with new or innovative framing systems. Traditional structural peer reviews may be performed at the request of the owner or developer, to expedite a building department review, or because it is required by the building code or performance-based design guide. These reviews generally occur in a cooperative environment. Other types of reviews can also occur. …
Modular, rapidly erectable, and deployable structures are critical for disaster relief, military operations, and the accelerated construction of bridges and buildings. Through various innovative means and methods, permanent or temporary structures can be rapidly constructed in challenging environments, such as rural and austere regions where access to construction equipment is difficult or in heavily congested urban locations where construction time is severely limited. …
A recent webinar on the “10% Rule” included in the 2018 International Existing Building Code (IEBC), attended by the author, discussed an exception in the code’s Section 502.5 that allows existing structural elements to remain unaltered if an addition to that structure results in a less than 10% increase in the element’s demand-to-capacity ratio. After the webinar, there remained the question, where was the companion webinar, the “5% Rule?” The 5% rule, otherwise known as the Prescriptive Compliance Method, is more straightforward and widely used. It is contained in IEBC Section 502.4 and states the following: …
As early as 1962, Douglas Englehart presaged BIM as “an evermore-detailed, interlinked structure, which represents the maturing thought behind the actual design.” Since this early vision, building designers have wholeheartedly adopted building information modeling (BIM), software-based design, and 3-D modeling. While BIM adoption has been praised for bringing efficiency to the construction process and benefits in coordination, it has also placed a new set of pressures on the structural designer. …
It has been a turbulent and unpredictable past twelve months. Still, it appears engineering firms were in a better position to respond to the interruptions resulting from COVID-19 than many other companies. With the necessary network infrastructure in place, many engineering firms effectively performed design/analysis and small team collaboration in a remote environment. At least early in response to the pandemic, many surveys showed utilization rates actually increasing within engineering firms. While many firms dodged a disruption bullet, not all managed to do so. Valuable lessons were learned about a firm’s resilience, lack thereof, and preparedness for disruptive events. …
Editor’s Note: Today, many firms have tackled remote work in response to COVID, and learned several lessons along the way. Although this article is about issues that arose well before the current pandemic, it is interesting to realize that today’s firms may very well be better positioned to create solutions like those presented here. …
Casa Adelante is a seismically resilient nine-story affordable housing project for low-income seniors, with 25% of the units reserved for formerly homeless seniors. The specially “tuned” reinforced concrete building uses self-centering walls on a rocking mat foundation. Lead extrusion dampers within the foundation control the seismic response. The building has been evaluated to have zero days of downtime for repair after a major earthquake, and the project received a Gold Rating from the US Resilience Council. …
When I was a kid in the 70s, there was a children’s TV show called Zoom. I wouldn’t say I liked it too much, and it didn’t last too long. It was reintroduced in the 90s and, again, didn’t stick. For understandable reasons, I suppose, this past year has had me thinking about that show and how little I suspected the word zoom would reenter my life in such a big way. A series of new software to install, learn, and make sure they are compatible with my hardware. The need to run many programs (Zoom, Hangout, Teams, Webex, Goto, Bluejeans, Connect) interchangeably depending on hosts. And a series of terms introduced into our vocabulary (zoom fatigue, zoom etiquette, virtual background, etc.). And now common phrases, “Can you see my screen,” “Can you make me the cohost,” and “Can you turn on your cameras so we can see you?” The current question in my mind is, where will this lead us moving forward? …
Structural steel has been a dominant building material for more than 100 years. Although steel is not considered a particularly remarkable material today, Vaclav Smil’s book, Still the Iron Age, illustrates how important iron and steel have been and continue to be in industrialized societies. For a structural engineer working on historic renovations and adaptive reuse of pre-war buildings, working knowledge of the history, development, and metallurgy of structural metals is necessary for the engineer to be effective and efficient. …