ASTM Specification: An Interview With Kim Olson

Peer Perspective: Kim Olson, Manager of Technical Initiatives, Construction Solutions, Nucor Corporation

With her wide variety of roles, Olson brings a unique perspective to conversations about ASTMs and best practices that come when specifying them.

Q: You’ve had a unique career path as a practicing engineer in both traditional and nontraditional roles. Could you describe your background in previous and current roles?

A: I started my career as a consulting engineer in Denver, Colorado. I worked for about seven years at Martin/Martin. Then, my husband’s job took us to Philadelphia, and that’s when my career transitioned to a more nontraditional one. I worked for Bentley Systems as an applications engineer for the RAM software.

I did that for about five years and found myself missing project design. So I started working with a former co-worker, Sam Rubenzer, at FORSE Consulting. While I was at FORSE, we started doing some technical consulting for the Steel Tube Institute. I worked on that account as a consulting engineer for about seven years.

About 18 months ago, I transitioned into the role I have now with Nucor. I’m currently the manager of technical initiatives for the Construction Solutions group. We work to be a resource, both technically and commercially, across all of the products under the Nucor umbrella.

Q: Can you talk a bit about your personal experience with HSS, HSS connections and the different ways you worked to improve the use of HSS through code committees?

A: Prior to working with the Steel Tube Institute, I had what I would consider a typical exposure to HSS. I had designed some structures, canopies, columns, trusses and things like that using HSS. I was lucky enough to practice engineering in Denver, where we designed our own connections rather than delegating the design to the fabricator, as is done often in the eastern half of the U.S, so I had some connection design experience as well.

When I came to work for the Steel Tube Institute as a technical consultant, I had a lot of studying to do. I really dove into research papers. I read every book I could get my hands on. I studied as much as I could to learn about HSS.

Olson goes on to explain that there weren’t a lot of resources on HSS available to engineers, and no one served as an HSS advocate on the code committees. Leveraging her position with the Steel Tube Institute to create educational resources is one way Olson worked to improve the use of HSS by engineers and designers.

Q: Can you think of any ways HSS are underutilized? Do you have any examples of unique or innovative ways to use HSS?

A: The use of concrete-filled tubes comes to mind. By filling an HSS section with concrete (or any cementitious material), you not only gain more strength — which is inherent to that composite section — but you also gain fire resistance. Members often require fire resistance, and this way, you don’t need to apply a drywall around the column or spray on fireproofing. Composite sections allow the designer to maintain the beauty of the HSS section but still get the fire resistance.

Olson also hopes to see the industry use HSS in beam applications where the member is eccentrically loaded. Rather than having a wide flange section with kickers that brace the bottom flange, a tube may be more economical to use. Reducing the number of pieces reduces fabrication and erection costs. Tubes are better able to resist the twist incurred when a member is loaded at an eccentricity, like is often the case for an exterior wall load.

It’s not something we always think about because wide flange sections are the bread and butter for beam sections. But there may be some applications where tubes shine. Mostly, I want to highlight that tubes aren’t just used in structures and columns. I think as structural engineers, we forget that these materials are being used in things like furniture, exercise equipment, trailers, farm equipment and many other places. When we talk about making changes to a specification, we need to think broader than just construction. We need to take a more global view of where these materials are used.

Q: What are some ways engineers can design HSS or HSS connections more effectively?

A: This is an easy one. It’s an easy one to say, although a harder one to put into practice. I mentioned earlier that typically in the eastern part of the U.S., engineers will design the member but not necessarily design the connections. In the west, I think we’re seeing more of that happen as well. I grew up engineering and designing all of my own connections and feel pretty strongly that it’s the right way to go. As the engineer of record, only I have the full picture of the member design plus what is required of these connections. The connections are the most pivotal factor to think about in HSS design because the HSS wall thickness often controls the connection capacity. So, if the member is designed without consideration of the connection capacity required, you might end up in a situation where upsizing the member is required after material has been ordered. It’s also uneconomical to try and strengthen or reinforce an HSS wall. It’s very important that engineers of record think about the connections as they are sizing the project’s HSS members.

Q: The technical article written this month compares various ASTM Specifications for HSS. What would you say is the most common question you receive on HSS ASTMs? How do you typically respond to these questions?

A: The most common question we get asked is about the availability of HSS. What sections are available throughout the U.S.? The Steel Tube Institute has a good tool, the HSS Capability Tool, that helps you search that.

It’s also important to note that in the past, the A500 Specification has had four different grades. In the beginning of 2021, grade A was eliminated because it wasn’t being produced and had a low yield strength. Being left with grades B, C and D, a lot of engineers still specify grade B. Domestically, all of the material produced now and for about the last 20 years meets grade C specifications. It’s best that engineers stick with grade C when they’re designing and specifying it in their general notes. A500 rounds are 50 ksi now, too!

Q: Of all the HSS ASTMs, A500 is by far the most common. What are the next most important ASTMs that engineers and designers should be aware of and why?

A: It’s important for engineers to know about ASTM A513 and ASTM A53. Frequently, these are substituted for A500. A53 is often specified for round HSS. In the past, it was thought to be a less expensive specification than A500 rounds. However, it’s only intended for mechanical applications. It’s meant to convey pressurized fluids and gasses, not used in a structure. There are tolerances absent from the A53 Specification that we want in our structures, so it’s important to avoid using it for that purpose. Also, it’s more expensive to produce than A500.

Olson goes on to discuss A513 and how it’s typically used for smaller HSS. If A500 isn’t available, a fabricator may suggest A513 as a substitute for A500. Be sure to note A513 doesn’t have a minimum yield strength associated with it, so engineers should ask for the material testing report (MTR) to ensure the material meets the strength required by the project.

Q: What are key pieces of information engineers should look for when reviewing an ASTM Specification regarding HSS?

A: As engineers, we typically look for yield and tensile strength and stop there. This isn’t unique to HSS, but what gets us in trouble is not thinking about tolerances when we’re detailing our structures. A500 is unique in that the tolerances are contained in that specification. We’re used to open sections’ (wide flanges, angles, channels) tolerances all being contained within ASTM A6. A500 HSS tolerances are contained in the A500 Specification.

Q: What is the most valuable HSS design resource for someone in your industry?

A: By far the Steel Tube Institute Limit State Tables. The Limit State Tables provide so much information. They provide two different values: a list to make sure you’re checking all the limit states that apply to your HSS connection and a roadmap to navigate those limit states since the AISC Specification has transitioned away from the tables that were in previous additions. 

It’s cumbersome for an engineer to know where to go and what variables to substitute for each limit state given in Chapter J and K, especially if you aren’t designing HSS connections day in and day out. The Limit State Tables provide an invaluable resource to be able to navigate those checks for each of your connections.

Q: What is one key piece of advice you’d give to aspiring engineers?

A: Find a firm where you can learn! I was very fortunate to grow up in a firm that does diverse work and values education. We had internal classes every Monday, and the focus on continuing education was key. Additionally, I was able to work on a variety of projects. Early on, I designed with all different materials on a variety of project types.

Don’t be afraid to try nontraditional jobs. If you try it and don’t like it, you can always go back to design. I did that and now I’m back in a nontraditional role. There are a lot of opportunities for people with backgrounds in engineering to use their knowledge in places outside of consulting.