Minn. Teamsters Push Gov. In Bridge Rebuilding

Teamsters Local 120, which represents nearly 14,000 members and is the largest Teamsters Local Union in Minnesota, is pressing Governor Tim Pawlenty and the state legislature for change to the state's transportation policy.

"The bridge collapse was a tragedy for the Twin Cities, for Minnesota and for the nation," says Teamsters Local 120 President Brad Slawson. "The horrific loss of lives -- including that of a Teamster delivery driver -- is testament to the need for fundamental change."

"Rebuilding the bridge is an important first step," continues Slawson. "However, the new bridge must represent more than a mere span of concrete and steel. Instead, it must serve as a monument to Minnesota's renewed commitment to safe, efficient and responsible transportation."

Teamsters Local 120 urged Pawlenty to view bridge reconstruction as a matter of practicality rather than politics. "Teamsters Local 120 members -- along with thousands of union members employed in the building trades -- are ready, willing and able to contribute to the
reconstruction of the I-35W bridge," Slawson says. "It's a matter of pride and patriotism. Allowing these union members to put their skills to work will mean getting a quick and quality rebuild. It will also provide good jobs to construction workers who have been idled by an industry slowdown."

Given the tragic circumstances, Slawson expressed confidence that Governor Pawlenty would not succumb to the political temptation of directing bridge reconstruction work to non-union contractors that traditionally support Republicans. "Safety, not politics, should be
Minnesota's first concern," he says. Slawson says he didn't think that Pawlenty's recent request for the assistance of Minnesota's congressional delegation in securing regulatory waivers should be used as an excuse to suspend labor standards.

However, Slawson says he is concerned about the Minnesota Department of Transportation's (MnDOT) pace in awarding preliminary contracts and requiring prequalification submissions. "Some degree of urgency is obviously necessary under the circumstances, but MnDOT must recognize that the tragedy of the bridge collapse does not somehow trump the applicability of state and federal labor laws during reconstruction," says Slawson. "Minnesotans support a reconstruction timeline that results in a responsibly built bridge that will safely serve motorists for years to come. They aren't interested in hurriedly and haphazardly assembling something more akin to a political prop than a long-lasting bridge."

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Bridges Will Rock -- Safely -- with New Quake Design

Bridges that "dance" during earthquakes could be the safest and least expensive to build, retrofit and repair, according to earthquake engineers at the University at Buffalo and MCEER.
The researchers recently developed and successfully tested the first seismic design methodology for bridge towers that respond to ground motions by literally jumping a few inches off the ground.

The new methodology allows steel truss towers that support bridge decks to be built or retrofitted at far less expense than conventional approaches, where each leg of a bridge tower is strongly anchored to its footing.

The research is funded by the U.S. Federal Highway Administration.

The design recently underwent successful testing on a model truss tower that is 20 feet high and weighs nine tons.

Testing was conducted on a six-degrees-of-freedom shake table in UB's Structural Engineering and Earthquake Simulation Laboratory (SEESL). One of the world's most versatile earthquake engineering laboratories, it is a facility within the UB School of Engineering and Applied Sciences.

"Our approach is unconventional, counterintuitive," admits Michel Bruneau, director of MCEER and UB professor of civil, structural and environmental engineering, who developed the new approach with Michael Pollino, a doctoral candidate in the UB Department of Civil, Structural and Environmental Engineering.

"With an earthquake, conventional wisdom dictates that the most important thing is to anchor the bridge tower," explains Bruneau. "The mass wants to overturn, so you have to tie it down."
To do that, he explained, the tower must be anchored with a very expensive foundation system, which in turn, subjects it to the full force of the earthquake.

"In this scenario, something usually has to yield," he says. "Here, we're standing that concept on its head. By letting the tower rock, we're significantly reducing the overturning force."
The UB engineers developed a design procedure in which the legs of the truss tower are disconnected from their base and briefly uplifted by a small amount if significant ground motions occur.

One of the options they evaluated includes using specialized devices to control the structure's uplift. The devices, called hysteretic or viscous dampers, some of which were provided by Taylor Devices, Inc., were inserted at the base of the towers to allow the tower to rock while absorbing part of the earthquake's energy and helping to control the amount of uplift to the structure.

During the series of tests at UB on SEESL's state-of-the-art shake table, the experimental truss tower fitted with these devices was subjected to ground motions simulating the 1994 Northridge, California earthquake; testing also was conducted without any devices attached, as the design procedure was developed to generally address performance both with and without dampers.

Typically, during testing, the tower's legs uplifted nearly two inches in the air for less than a second. For some of the free-rocking cases, the tower legs lifted nearly four inches.

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