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Dordt College News

Vander Werff expects his research to save lives and bridges

March 14, 2014

Engineering Professor Justin Vander Werff is still in the throes of sifting through data before submitting his final conclusions about integral bridge design for his Ph.D. degree. The awarding of his Ph.D. will give official recognition to work that the California Department of Transportation, CalTrans, has been itching to implement for some time.

Vander Werff’s cutting edge research demonstrates that using integral girder connections make accelerated bridge construction viable. In this method of building bridges, as many concrete parts as possible are precast and shipped to a location, where they can then be set up quickly. Vander Werff gives the example of a bridge near Council Bluffs, Iowa, that was put in place in 16 days, a significant contrast to the six months it would have taken using traditional methods.

“This is especially important in urban areas where diverting bridge traffic can cause major traffic and economic problems,” says Vander Werff.

But uncertainty about the reliability of the connections that join the precast concrete pieces has meant that accelerated construction has not been used in major metropolitan areas in high seismic regions, especially in metro areas on the West Coast where it is most needed. Typically, pin and roller connectors were placed on top of the cap beam to support the girders. Vander Werff’s design uses a girder that, in effect, runs “through” the cap beam.

Iowa and other states in the Midwest, as well as Florida and Texas, have been using accelerated construction methods for some time. But concern with seismic behavior has prevented widespread use of such techniques in other areas. In major California earthquakes in 1989 and 1994, it was at the connections that bridges and other precast concrete structures often collapsed. CalTrans has been funding research on better ways to connect the elements of bridges since 2007.

Over the past three years, Vander Werff has tested ways of connecting girders and cap beams that withstand both displacement and rotational earthquake effects. He focused primarily on effects resulting from horizontal seismic acceleration, the movement that has traditionally been the primary focus in structural earthquake research. The 2011 earthquake in New Zealand, which exhibited dramatic and unexpected vertical acceleration because of geological factors at play in that event, prompted Vander Werff to also test how his way of connecting parts would respond to vertical effects.

“Because of the vertical acceleration it produced, the New Zealand earthquake caused more death and damage than would have been expected from a 6.2-magnitude earthquake,” he says. New Zealand, along with Japan and the United States, is a leader in earthquake research and had in place data collectors that provided a wealth of information about the quake’s movement. Vander Werff used that data to help test the effects of vertical acceleration on his connections after that event.

“We’ve found that this connection works as we expected, for both horizontal and vertical effects,” he says. In the process, he demonstrated new steel reinforcement techniques that are very effective in providing robust seismic connections. He’s also shown that some reinforcement details used currently because of uncertainty about how the connections might hold up aren’t helpful and simply increase costs.

“It’s really exciting to be serving in a way that can help keep people safer,” says Vander Werff. “Because it falls in the area of public works, bridge designers are generally working for the public good rather than for economic benefit.” This leads to a level of sharing and collaboration that Vander Werff says usually does not happen in a competitive corporate environment.

“More progress is made when people work together,” he believes.

Vander Werff is confident that the research and testing he’s done will have a significant and positive impact on bridge building and will reduce loss of life and damage to structures during extreme events. The more he works in his field, the more he realizes how much he and others don’t understand about how things work.

“That doesn’t scare me, but it does make me want to work harder. And it makes me more thankful for how God continues to reveal how his creation behaves,” says Vander Werff. “The more I learn, the more I appreciate creation’s complexity and the task I’ve been given to develop it in ways that value its resources and people.”

Doing this kind of research also makes Vander Werff feel a sense of humility.

“I couldn’t be a humanist and an engineer,” he says. “We can’t save the world by what we do; there are too many things we don’t know and can’t control. But we can deepen our understanding of God’s glorious and complex creation and make a difference in people’s lives.”

Vander Werff’s students benefit from his work, too, as he shares examples of the work he’s doing to demonstrate material he teaches. It gets them out of the textbook and closer to the world in which they’ll work.

Vander Werff hopes to finish his research in time to receive his Ph.D. this spring or summer. He expects to continue earthquake-related research during his summers, giving his students opportunities to work alongside him and gain the kind of experience that is increasingly important for getting into graduate school or the profession.

Back after 16 months of residency for his Ph.D. program, Vander Werff says, “It’s such a blessing to be in the Dordt engineering department where people work together for a purpose other than making a name for yourself. There’s no place I’d rather be.”

It may be that approach that has inadvertantly made a name for Vander Werff.


SALLY JONGSMA

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