Change Leader Full Interview: Early Partnerships Among Engineers and Solution Providers Lead to the Best Projects
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Ben Eder is ITT Enidine’s global product manager for large bore shock, infrastructure and seismic components.
V1 Media: Please provide a brief background of your education and career before ITT Enidine.
Eder: I’m a mechanical engineer by education. I also have an MBA, so I have a little bit of business exposure as well. My design and technical background is mostly mechanical engineering, specifically hydraulic design. Earlier in my career I designed water pumps for a different division of ITT in new product development specific to chemical and water applications.
V1 Media: Please describe your current position at ITT Enidine.
Eder: My current position is global product manager. More specifically, I’m responsible for business development, consulting directly with structural engineers or specialty firms that work in the realm of improving structural performance of buildings. The majority of my role today is really focused on speaking with structural engineers and working directly with our Enidine engineers to better understand the needs in the market. As engineers, we push the envelope of what buildings, structures and the performance of those structures are supposed to be like in real-life applications. Then we work backwards toward what technology, products and design services can ITT Enidine provide to increase supplementary damping for these types of structures. It could be anything from low-rise buildings, to mega-tall skyscrapers. The majority of time is working on the problems of today, while also focusing on future issues or developing trends in the marketplace so that ITT Enidine continues to be seen as a leader for producing and developing next-generation solutions for structural supplementary damping.
V1 Media: Could you describe some of these needs as well as the challenges engineers are running into, where they’re looking for help and guidance?
Eder: There are many different reasons why a structural engineer may consider a supplementary damping scheme, and there are a many different technologies available on the market. ITT Enidine, specifically, is focused on hydraulic damping. Engineers, depending upon where a building is built, what type of structure it is–its intended use also comes into play, might have to consider certain factors such as seismic considerations or wind considerations, or both at the same time, on top of other requirements. For example, it could be a hospital in a high-seismic area, or a mid-rise structure that also has wind considerations. All of these possible factors come into play when designing a structure. A structural engineer has several technologies available to them in terms of adding supplementary damping. It could be as simple as adding more structural steel, adding more mass to their structure.
But these days, a big driver in looking at supplementary damping systems is really specific to economics and building performance. There could be considerable savings from investigating and eventually deciding to go with a supplementary damping type product.
Structural engineers have to consider all of these factors within a single design envelope. Every building’s structure is unique, so every structure they’re designing starts from scratch and has its own unique characteristics and needs in terms of structural damping. Ultimately, there’s more than one good solution. The idea is to work into a solution that’s the most economical for the client–the owner of the building–that’s also achievable in real-world practice.
V1 Media: Could you define what supplementary damping is and why an engineer might need or not need supplementary damping?
Eder: It may be easiest to describe an example in the case of a skyscraper. The trend today in skyscrapers, especially if you look in developed cities, is that ground space is at a premium. There is no room left on the ground, and any available land is very expensive, so the only way to build is up. There’s a trend of what would be considered slender skyscrapers or slender mega-talls, which generally have a height ratio of one to seven, and there are buildings being built that have a slenderness ratio of one to 24.
A structural engineer has a basic framework of what the expectation is: that they will be designing a tall, slender structure, and then there are factors they have to deal with in terms of the ambient environment. The biggest consideration generally is going to be wind, although seismic design does come into play. New York City, for example, is a known seismic zone, but generally the driving factor is wind.
When you start talking about a super-slender, mega-tall structure, there are only certain building materials and techniques available to add enough damping to the structure to mitigate issues such as acceleration. These buildings are designed so that they can sway up to several feet at the top of the building in any direction. When a structure is moving that much, how do you keep your occupants comfortable during these conditions? One way to do that is to add a supplementary damping system such as a tuned mass damping system.
ITT Enidine would supply fluid viscous dampers for that tuned mass damping system. Essentially, it’s designed to reduce the acceleration of that movement so it’s imperceptible to humans, so people don’t get motion sickness from the actual movement of the building that’s inherent in the structure. In adding that supplementary damping system, engineers can create a lighter, more-flexible structure that’s more economical than having to build a heavier structure that has more inherent damping, allowing them to use lighter materials and less material, which more than offsets the cost of that supplementary damping system and, in the end, delivers a high-performance building at a lower cost for the owner.
V1 Media: Could you describe some non-supplementary damping techniques, some of their weaknesses or strengths, and why you might need a supplementary system? Also, could you go over what your fluid viscous dampers are as well as describe some other supplementary dampers out there?
Eder: Every structure has inherent damping. The Empire State Building was a very tall building at the time it was built. Ultimately, the way that building increased its critical damping ratios was essentially to use more structural steel, so that’s one way; the structure itself has its own inherent damping. That’s the balance engineers are working with, trying to reduce the amount of material they’re using or use more-modern materials that are lighter and more flexible vs. using just more physical mass, which can be expensive.
ITT Enidine fluid viscous dampers are essentially like any other supplementary damping device, where the damping comes from the dissipation of energy introduced into a system. Any structural system could have two main factors: seismic or wind. Those factors represent an energy input into the structural system. The function of a fluid viscous damper is to dissipate that energy by forcing hydraulic fluid through an internal orifice or opening. The friction that’s created by the structure acting upon the damper itself is pushing that fluid through an orifice, this creates friction that converts kinetic energy of the structural movement into heat, and that energy is then dissipated.
Most other energy-dissipation technologies work upon the same principle. There is friction damping, for instance. It’s very similar to a brake pad in a car. That friction is converting kinetic motion into heat via friction. There are a lot of other technologies out there as well, such as buckling restraint braces (BRBs). They work under a similar principle. Each type of technology has its own pluses and minuses. Where one type of technology may shine, another may have limitations. The product that ITT Enidine makes–fluid viscous dampers–isn’t suitable for every type of application, but it does lend itself to quite a few of them in terms of being the most economical and best performing for certain applications., mostly specific to tuned mass damping applications, it’s very good. ITT Enidine viscous dampers are able to dissipate a high amount of energy in a small space. The function of a tuned mass damper is that it is usually at the top of a skyscraper, so space is at a premium and that floor space at the top of a skyscraper is usually worth the most dollar value, so being able to dissipate a high amount of energy in a small footprint is very desirable. Structural in-frame damping actually being an integral part of the structural system, fluid viscous dampers can easily fit into walls where required in the design. They have a long maintenance-free life, so they are able to last a long time within that structural system, needing little to no maintenance or inspection unless a large seismic or wind event occurs: i.e., a hurricane or tornado or a large-magnitude earthquake that may be near the original design level for that structure.
V1 Media: Do fluid viscous dampers and other large dampers work automatically based on how much energy or motion is in the system, or is there any type of input or adjustment that needs to be made by people or the systems?
Eder: Fluid viscous dampers add stiffness to a structural system. It depends on the application, but essentially they do nothing until they’re acted upon. Very simply, a fluid viscous damper is a velocity-dependent device, unless there is an input acting upon it; it does nothing. Once that input acts upon it, which generally would either be the mass of a tuned mass damper or the structural system, if it’s an in-frame type of application, it will respond accordingly based on its design parameters. For any amount of input, that fluid viscous damper is dissipating some amount of energy.
The uniqueness in working with structural engineers is that you have a device that has to consider many different application parameters. For a mid-rise structure designed in a high seismic zone, you’ll have to consider not only the structure but, specific to a fluid viscous damper, you have to consider the response, the seismic zone that it’s in, the response you want to see in the structure, and the damping you need in the structure. Seismic displacements can be very large, so there can be very large ground motions that require a damper that could have a displacement of up to 7 to 10 inches. Then there also could be wind considerations, where it may not be a high-rise structure, so you’re not going to see large movement displacements due to wind, instead you may encounter very small displacements. You have a wind input that may act upon the damper in those very small amplitudes, say maybe a quarter of an inch. ,therefore you have to design the damper that can add the required amount of damping across a range of different external energy inputs to that structural system.
V1 Media: What’s the ideal relationship between engineers and solution providers such as yourself when working on a project to try and find the best solution? What’s the best way to go about that interaction?
Eder: I always say the earlier the better. I think many product manufacturers specific to large building projects would say that very same thing, because building projects are long-cycle projects from concept to finished building can take years to complete. We’re talking a longer design cycle compared to other applications. Early on in the process, a structural engineer has to make some critical decisions about what type of philosophy they’re using with their structure, are they going to consider supplementary damping vs. designing their required amount of damping into the structure itself? Those types of decisions can be driven by site considerations, seismic zones and wind. Is it near the coast, or is it near where wind may be a large factor in the design of the structure?
Another consideration is the use of the structure itself, is it a hospital or a school vs. an office building? The earlier in the design process that a structural engineer and manufacturer are in discussions helps to guarantee that the end result of the structural design process is a high-performing structure that’s economical and achievable in practice. If a structural designer who’s not very familiar with the available damping products, designs a structure and specifies a fluid viscous damper that may be physically too large or needs a performance range that’s physically impossible to achieve, that structural designer now has a major problem, because they now have to go back to the design phase to reiterate their structure and get back to using a product that actually exists or is achievable in practice.
Even further, it’s much better for a structural designer to understand the difference between “standard” and “custom” products, because customization costs money. If a structural designer can iterate their structure and tune it, if you will, to using a standard catalog-type supplementary damping, it ends up being a much more economical design for the client. We’ve seen many times where we will get a project specification, and the requirements are perhaps achievable, but there could be issues where there is not a place in the world where you could physically test this product.
ITT Enidine has capabilities to design almost any damper imaginable, but then there are questions of actually testing that product or proving it out in real-world applications. It could turn into a product that would require materials that are unavailable or exotic and expensive. Our focus with working with structural engineers early is to not only guide the structural engineer toward what’s actually possible, what’s economical and what makes sense from our perspective, but then also understanding the structural engineer’s perspective as to the type of performance they’re looking for and what they may be able to endure in terms of economics, because maybe they stand to gain in other areas of their design as well. Working together helps us balance those two factors to produce a high-performance building at the most economical cost.
V1 Media: What are some of the best ways structural engineers can find out about all the latest and best options they have available? How can they know what they have to choose from so they can come up with the best designs?
Eder: That’s the tricky part. In supplementary damping, particularly fluid viscous dampers, there are only a few companies in the world that make this type of product, and there is not a dictionary for trying to find answers on fluid viscous dampers or any other supplementary damping product, because building structures are unique in and of themselves. In certain parts of the world, you may see copycat skyscrapers built next to each other or mid-rise buildings. In places such as Seoul, South Korea, there are many buildings stacked upon each other–they look almost exactly the same. But in the United States, almost every building project is a unique entity. The solution that may have been used in that structure was slightly unique, so you can’t go to a manufacturer and understand all the differences or capabilities that may be available to you by looking at what a manufacturer offers as standard product. The best way to get this type of information is to get connected with the manufacturers’ engineers.
My function is to go out and facilitate those discussions between our engineers here at ITT Enidine and those structural engineering teams who may be looking for a new way to improve their designs or have a structural design that may have some supplementary damping needs. The best way is to speak to manufacturers’ engineers early to start understanding what’s possible and what may be the most economical route to take for a product or solution. The farther along you get into the design process, working toward a solution that may or may not exist, is not the best route to go. Understanding and having someone to call if you have questions or see a structural design going a certain direction, it’s always good to have checks along the way, with the manufacturer’s engineers, to make sure you’re on the right path, and then to understand what the options may be at certain milestones along a project to take the best direction, either economically or schedule-wise or other factors not seen by the structural engineer.
V1 Media: What might be some advice you’d give to engineers dealing with solution providers to try and find the best options out there, whether they’re damping or other things engineers might be working with? What are some of the best ways to find the best solutions from providers?
Eder: Everyone has limited time in a day, and a structural engineer is no exception. There are structural engineers who are not hesitant to go out and contact manufacturers; and manufacturers, in general, are very receptive to offering assistance or guidance and information that may help them along their path. But in my years of doing this, I often see structural engineers get ahold of one manufacturer and generally stop at that. They get someone who may help them with some answers, and that’s good enough for them at the time.
What structural engineers may not realize is that every manufacturer is only going to provide an answer based on their technology, knowledge and knowhow. One manufacturer’s best answer is going to be different from another’s in a comparable type of product or even just different types of products that achieve the same thing. As in the world of supplementary damping, there are different products out there–different technologies out there–and within those groups, there are also different manufacturers producing them. In the world of structural engineering and bid-spec type work, there’s a big drive with a lot of product manufacturers to work to specify a product in a way that helps that manufacturer get locked in to that bid and make it difficult for their competition to provide a solution that’s specified.
Unfortunately, that’s not the best route for the structural engineer’s client, generally the building owner, because that building owner needs to have multiple companies and manufacturers capable of providing that solution to keep competition among those manufacturers and for that building owner to get the best economical price for the solution. That often doesn’t happen, because structural engineers are only considering one input. I would say it makes sense for structural designers to really try to investigate their options. If they’ve decided a certain technology is likely their best choice, and I think there’s enough information available today that a structural engineer could do that, that they then consult more than one manufacturer to understand what each one has to offer in terms of their technologies and products as well as to understand the cost of those specific technologies, so they then can develop the solution in a way that can encourage competition among manufacturers and ultimately be the most economical for their client.
There’s another trend I’ve seen from structural designers. If you’re to the point of knowing you’re going to specify a fluid viscous damper in the design, and let’s make the assumption that it’s a common size with a common range of performance that any manufacturer who specializes in this type of product could make, I see many of them mismatched. Every fluid viscous damper for any type of building project is tested in the lab to guarantee product quality as well as completely understanding the nature of the performance of that product specific to the structure for which it is designed.
With any product, precision costs money, especially with a mechanical or hydraulic device. There always will be an amount of performance tolerance that happens when you’re producing 20 to 100 dampers or more. For a building project, there will always be a slight amount of variation from damper to damper. Each damper is designed to a certain performance requirement, therefore there is a set number of input parameters that go into the design of a product, and then a testing plan is also associated with the testing required for that specific product.
The trend I’ve seen is a mismatch between the damper that a structural engineer has asked a manufacturer to design vs. the testing requirements they’ve asked that manufacturer to perform. Structural engineers often desire to “over-test” the damper to know its limits, but a lot of structural engineers don’t realize that you can’t over-test a damper, because it’s purpose-designed. It’s designed specifically to operate within the parameters they gave it to be designed for. If you require testing to be done outside that range, the testing requirements begin to dictate the design of the damper itself.
For example, in an energy dissipation test, which is the primary function of a fluid viscous damper, a performance parameter can be specified for the design of the damper to dissipate X amount of energy per hour, and the testing requirement could actually specify to dissipate two or three times that amount of energy, which could actually drive the physical size of the damper to be two to three times larger than what the design parameters state. In short, it goes back to consulting with the manufacturer and that a structural engineer can’t necessarily make assumptions about what’s possible or that you’re able to over-test and find the limits of the damper. It has to be understood that it’s a specific device designed to do a specific job, and the way to test that device is through the specific job it’s supposed to do.