Insight into the new Limit Design method for special reinforced masonry shear walls – what it offers, how it was developed, and a glimpse at possible future developments.
“Limit Design is a bold step for masonry engineering and it marks it as an even more significant structural material.” That may be my favorite comment from my tenure as the MSJC Chair. It came upon the successful balloting and adoption of the new Appendix C – Limit Design of Masonry. …
This is Part 3 of a series of articles introducing illustrative examples of changes in design and construction codes, standards, regulations and practices that have followed catastrophic failures of construction cranes. Part 1, in the December 2010 issue of STRUCTURE®, focused on bridges, Part 2 in the April 2011 issue focused on buildings, and Part 3 is devoted to construction cranes.
It is a credit to our structural and construction engineering professions that failures have been and continue to be used to improve design, construction and regulatory practices. We do not just pay up, rebuild and walk away – we delve, we learn, and we improve. …
The most effective people I know always seem to have time to take care of everything. They volunteer, they exercise, they spend quality time with their families, they seem to do it all! When I was in college, I asked one of my teaching assistants how he made time to do everything that was expected. His answer was simple: “You always have time for whatever you make time to do.” I’ve thought a lot about it over the years and often think about how wise that simple statement is. It really is a matter of deciding what you need to prioritize, and the rest should work itself out. …
As a part of Pennoni’s on-call contract with an existing client, the Philadelphia structural division investigated and developed repair bid documents for an existing, three-level, 1,200-space precast concrete parking garage during the last quarter of 2012. Part 1 of this series (September 2013) described the existing structure and summarized observations and material testing results. This article presents an analysis of those findings. …
The term “sliver building,” according to the New York City (NYC) zoning code, is specifically reserved for a tall building or enlargement that is 45 feet wide or less. In many cases, such buildings are restricted to a height equal to the width of the abutting street or 100 feet, whichever is less. However, when considering the structural stability of a building, a “sliver building” is commonly a narrow building having a large aspect ratio (height to width). Even though a building may not specifically be designated as a sliver building according to the local zoning code and building department, engineers often encounter similar conditions which often present stability issues due to the narrow width when resisting lateral loads. …
There is an important design consideration for wood floor framing that is not likely to be found in building codes or design standards – differential deflection. This issue is often overlooked, but can lead to significant performance problems. Differential deflection, as described here, is the change in elevation from one framing member to the adjacent member. Differential deflection may escape consideration. Building code requirements and design standards for deflection typically pertain only to the deflection along the span length of an individual member. Problems related to differential deflection can arise when one long span member deflects in flexure, within building code limits, while the adjacent member does not, often due to different support conditions or stiffness (Figure 1). …
Structural Forum is intended to stimulate thoughtful dialogue and debate among structural engineers and other participants in the design and construction process. Any opinions expressed in Structural Forum are those of the author(s) and do not necessarily reflect the views of NCSEA, CASE, SEI, C3Ink, or the STRUCTURE® magazine Editorial Board.
Generally speaking, structural engineers first gain confidence that we can know the true behavior of structures during our engineering education, when we become exposed to the sophisticated and beautiful theories of structural mechanics. …
In his entry on “risk” for the Stanford Encyclopedia of Philosophy, Sven Ove Hansson noted that there are at least five relevant senses of the word in common usage today: …
To many A/Es, the words “building code” have a distinctly negative connotation. This is not entirely surprising – the words often come up in the context of an obscure requirement that no one can explain. Or even worse, two obscure requirements that appear to contradict each other. Nevertheless, being able to design to the applicable building code is a non-negotiable element of an A/E’s work. …
After fire exposure, design professionals are sometimes called upon to determine if the charred heavy timbers (Figure 1) are safe for future use without additional support or repairs. In this article, the authors present a sequence of reasoned steps that will help design professionals analyze charred timbers and gain the type of information needed to decide whether the charred timbers are adequate based on the applicable building code. …