Jon Magnusson: 'The demand for high-rises is strong'

Jon D. Magnusson, PE, Hon. AIA, is chairman and CEO of Magnusson Klemencic Associates, a Seattle-based structural and civil engineering firm. Recently named "Engineer of the Year" by the American Council of Engineering Companies of Washington, Magnusson serves on the National Fire Protection Association's High Rise Building Safety Advisory Committee and the Structural Engineering Institute's National Board of Governors, and is involved with the National Council of Structural Engineering Associations. Under Magnusson's leadership, MKA has earned national design excellence awards from the American Council of Engineering Companies in 13 of the last 17 years.

Dave Barista: You have been a vocal critic of the recommendations published in June by the National Institute of Standards and Technology, based on its $16 million study of the World Trade Center disaster. Where do NIST's recommendations fall short?

Jon Magnusson: They completely missed the two most important steps. First, teams need to clearly identify the design hazards that they're going to consider when designing a building. Are they going to consider a bomb? If so, how large is the bomb? Are they going to consider impact from an airplane?

Once the design hazards are established, then they have to establish the performance objectives for the building. In the world of earthquakes, for example, we consider the size of seismic events. For a small earthquake, we may have a performance objective of no damage and no injuries. For a moderate quake, we're willing to accept some damage and minor injuries. For a large event, the building may need to be torn down, but we'll maintain life safety.

The importance of establishing design hazards and performance objectives at the project outset was totally absent from NIST's recommendations. And yet, that should be the initial step in all projects.

DB: That said, you do agree with about half of the 30 recommendations. Which ones are the most intriguing?

JM: About half of the recommendations are not building code changes, but more operational recommendations, such as improved communications standards. I like the idea of better radio communications among first responders. NIST is also urging for more industry research on certain materials and systems, like ways to make fireproofing tougher.

DB: Your firm has employed some very interesting structural solutions for high-rise structures, especially to meet earthquake- and wind-resistance performance objectives. Which ones show promise for use in a great number of buildings?

JM: I think the "sloshing" damper has a lot of promise. It involves placing a giant tank of water at the top of tall buildings to help with wind control in mainly non-seismic areas. We used it a few years ago for a very tall, slender building in Hong Kong, called Highcliff Apartments. It's a passive technology, so it does not require energy and needs very little maintenance.

One service that we're pushing hard right now is performance-based design. Instead of using the prescriptive methods of the codes in terms of rebar size, tie spacing, etc., we perform an advanced analysis of the actual structural demand on every single element of the building, and then place the steel and rebar where it's needed most. Current building codes do not do a good job in this area. For example, they tend to call for too much rebar in places where it's really not needed. We're working on several buildings in California where we specified more rebar down near the base of the shear concrete wall, where the highest earthquake demands are, and less rebar in the upper parts of the wall. Because we're not using the cookbook approach of the code, we have to go through an alternative design procedure, which involves convincing peer review teams of engineers that the building will perform the same, or better, than the prescriptive code. We create detailed computer models that simulate, for example, a couple minutes of an earthquake to show exactly what's happening to different parts of the building during the time of the earthquake.

DB: You say these buildings will perform better using performance-based design, but does this approach save costs for the owner?

JM: Oftentimes it does. Certainly, it puts the money in a better place. In some cases, it eliminates parts of the structure that don't do much.

DB: After 9/11, the common thought among Americans was that the market for high-rise buildings was dead. Yet, skyscrapers continue to be built at a torrid pace. Why?

JM: Some of the initial emotional reactions to the horrible events that we saw on 9/11 were just that. All the reasons that existed for tall buildings before 9/11 are still valid reasons today. People want to live close to city centers, and because cities don't have the space for sprawl, they have to go up. Plus, people like the views from high-rise towers, and corporations like the prestige that comes from a landmark building.

Right now, there's unprecedented demand for high-rise buildings. We're performing more high-rise work this year than in another other year in our firm's history. In Chicago alone we have 550 collective stories of high-rise construction going on right now. That's the equivalent of five Sears Towers!

DB: What are the hot sectors within the high-rise market?

JM: The demand for residential towers is incredibly strong right now. We're working on high-rise housing in Chicago, Seattle, San Francisco, Los Angeles, San Diego, and New York. Las Vegas and Miami are also hot markets.