8:54 a.m., April 30, 2010----The opening of the Second Blue Water Bridge, between Port Huron, Mich., and Point Edward, Ontario, in 1997, marked the culmination of years of work on a new design code aimed at providing uniform safety by using a statistical basis for linking the loads on a bridge to its resistance, or ability to withstand that load.

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John Kulicki, chairman and CEO of Modjeski and Masters in Mechanicsburg, Pa., was a key player in the development of that code, the AASHTO Load and Resistance Factor Design (LRFD) methodology, which has gradually replaced more traditional design approaches. He shared the history of the LRFD with an audience of more than 200 during the fifth annual Arnold D. Kerr Lecture in Engineering Mechanics and Design at the University of Delaware on Wednesday, April 28.

Despite his conviction that the LRFD is a robust design approach, Kulicki reminded the attendees, many of whom were engineering students, that design codes are not perfect.

“There's a tendency for young engineers to think that these codes are divinely inspired,” Kulicki said, “but nothing could be farther from the truth. They're developed by people and implemented by people. There is no perfection in the real world. Our goal is to keep the risk tolerably small while still building bridges affordably.”

Kulicki likened the development of the new code to the evolution from DOS to Windows in the PC world. “Adoption of the LRFD represented a switch to a more robust, more expandable platform,” he said. “And as with the changeover to a new computer operating system, there was a learning curve and some headaches during the transition, but its benefits and logic have become apparent over time.”

The process, however, was long and at times tedious. Kulicki said that the committee writing the specifications received 12,000 comments from the hundreds of people who reviewed the four drafts of the document.

Even since its official adoption, the code has undergone multiple iterations to accommodate such issues as heavier trucks and new construction materials. For example, in 2007, the seismic specifications were modified, and in 2008 a new specification was developed for hurricane loads on coastal bridges.

A major issue that remains to be addressed is scour, a term used to refer to the removal of founding materials from around bridge abutments or piers by rapidly moving water. Scour scoops out holes around these structures, compromising the integrity of the bridge. “Everything else pales in comparison to what dirt does in the face of water,” Kulicki said.

He also admitted that the design code project will probably never be truly finished. “We follow nature in our learning. Every time there's an earthquake, we learn something new. So there are probably other things missing from the code -- we just don't know what they are yet.”

To demonstrate the code's evolution, he showed photos of the 2004 version, at 500 pages, and the 2009 version, at 900 pages.

His next slide? A picture of a handcart, which Kulicki said may have to replace the three-ring binder in the future as more details are added to the specifications.

A graduate of Lafayette College and Lehigh University, Kulicki has more than 35 years of experience in virtually all aspects of bridge analysis and design. He was elected to the National Academy of Engineering in 2006 for “the design of major bridges and for leadership in the development of load and resistance factor design specifications.”

Sponsored by UD's Department of Civil and Environmental Engineering, the lecture series was initiated in honor of Arnold Kerr, professor emeritus of civil engineering, upon his retirement in 2004. Kerr is an internationally recognized expert in engineering mechanics, with a particular focus on railway engineering.

Article by Diane Kukich
Photos by Doug Baker