UM, South Carolina Researchers Help Develop Bridge-Monitoring System

Bolstering the nation’s infrastructure is a hot topic at the moment due to the government’s massive $787 billion stimulus package. One key point often overlooked in the call for new construction is the need to ensure the safety of the existing system – particularly bridges. According to the Federal Highway Administration, about 10,000 bridges are built, replaced, or rehabilitated annually but at least seven times that number exhibit defects of some degree.

In an effort to improve the monitoring of these spans, the National Institute of Standards and Technology has launched a $14 million effort to create a structural health monitoring system for the nation’s bridges.

Virginia Tech's Center for Intelligent Material Systems and Structures has teamed with Physical Acoustics Corp. of Princeton Junction, N.J., to come up with a system that will use small low-maintenance sensors to detect flaws in bridges. Their efforts are in conjunction with researchers at The University of South Carolina and the University of Miami, who are working on a system for “harvesting” that data for inspectors to interpret.

“Our hope is that at the end of our five-year effort we will have produced a soda can-sized object that can be provided to bridge owners to constantly monitor their structures in a safe and inexpensive manner,” said CIMSS director Dan Inman.

The need for such monitoring systems was tragically underscored on Aug. 1, 2007, when the Interstate 35W bridge in Minneapolis collapsed during the afternoon rush hour, killing 13 people and injuring 145 others.

Federal investigators later found that gusset plates that held the trusses together beneath the 40-year-old span were undersized and inadequate to support the intended load of the structure. Fracturing in the plates was found in not less than eight joint locations in the main center span.

An inspection of more than 750 bridges of similar construction across the United States was launched by the Department of Transportation in the wake of that finding. Many state transportation departments ordered similar evaluations as well.

The devices would be the core of a system that would provide continuously updated information on the structural health of the monitored structures. The data they produced could be used to prioritize bridge repair operations and would also be able to provide almost instantaneous information about extreme events such as collusions.

Cracks and flaws that emerge in a structure over time – like the fractures in the I-35W bridge – emit a distinct acoustic wave pattern that the devices can detect and record.

According to Inman, the devices his team is working on would convert the motions and vibrations in the bridge into electrical energy using piezoelectric materials. A similar type of reaction occurs when igniting a gas grill that uses a type of piezoelectric device to convert the energy of pressing the button into an electric charge that lights the gas.

The data will then be sent by a wireless system to be evaluated using a continuously updated computer model. The process would eliminate the need for regular sensor maintenance of structures and improve the effectiveness of onsite inspections.

Further, the system’s compact size means installation and maintenance would be minimal in terms of cost and difficulty.

Georgia Contractors Hold “Safety Stand-Down”

Commercial construction sites across the state of Georgia recently ceased all work to hold a “safety stand-down” where crews received safety training on fall protection. The program was developed by the Georgia Branch of Associated General Contractors, with the support of the Occupational Safety & Health Administration.

“Falls represent one of the primary causes of fatalities and injuries on jobsites,” said Michael T. Dunham, executive vice president of the Georgia Branch AGC said in a statement. “We developed this safety stand down to heighten awareness among workers and provide real-world training on how to protect themselves and coworkers.”

McCarthy Building Cos. hosted an event at its 10-story Parker Petit Lab project on the Georgia State University campus in Atlanta, which included participation from more than 200 construction employees.

Leo A. Daly Acquires Schwab, Twitty & Hanser

Omaha, Neb.-based LEO A. DALY acquired Schwab, Twitty & Hanser Architectural Group, an architectural and planning firm based in West Palm Beach, Fla. STH will conduct business as STH, a LEO A DALY Co.

Obama Reverses Bush Labor Pact Ban

As Congress negotiated billions of dollars in potential federal funds for construction through the economic stimulus bill, President Barack Obama moved to bring project labor agreements back as an option on federally funded projects. The president issued an executive order Feb. 6 overturning a Bush administration ban on federal PLAs and opened the door to such pacts on projects of $25 million or more.

The executive order re-instates much of the guidance on PLAs that was in place during the Clinton administration—and could potentially expand their use. The order also keeps a promise to organized labor to advocate for their interests.

Obama’s order also provided a basis for expanded use of PLAs. The order calls on the director of the Office of Management and Budget to recommend in six months whether broader use of PLAs on federal and federally funded contracts would help “promote the economical, efficient and timely completion of such projects.”

Mark Ayers, president of the Building & Construction Trades Department of the AFL-CIO, praised Obama’s action, saying it would benefit both union and non-union workers.

But Associated General Contractors of America warned that the executive order had the “unfortunate potential to limit contractors’ ability to compete for projects” at a time when millions of construction workers have lost jobs. “Given that federal agencies have no demonstrated expertise in writing contracts that cover contractors and their employees, we strongly encourage officials to exercise the discretion this order provides and avoid government-mandated labor agreements,” said Stephen Sandherr, chief executive officer of AGC of America, in a statement.

The order “opens the door to waste and discrimination in federal and federally-funded construction contracts,” added Kirk Pickerel, president of Associated Builders and Contractors, whose members are exclusively nonunion. “This action removes the safeguards that prohibited discrimination based upon union affiliation in the awarding of federal contracts.” Pickerel claims that such agreements could increase construction costs between 10% and 20%.

Among the provisions of the order, any agency using a PLA would need to show that such an agreement would advance the federal government's interest in achieving economy and efficiency in procurement; producing labor-management stability; and ensuring compliance with laws and regulations governing safety and health, equal employment opportunity, labor and employment standards.

-- By Bruce Buckley

Bayview Construction Wins National Safety Award

Bayview Construction of Stuart, Fla., was recognized for its safety by winning the national 2008 Safety Award for Excellence from the National Builders Association at the group’s recent meeting in Las Vegas. The company won first place in the light commercial contractor division.

Bayview Construction was able to demonstrate owner and upper-level management focus on safety, effective safety programs and procedures, hazard prevention and control, and safety and health training and education.

Acousti Engineering Co. Opens Venice, Fla., Branch

Acousti Engineering Co. opened a new office in Venice, Fla. This is the company’s 11th office in the state of Florida. The firm is an interior finish contractor that specializes in acoustical ceilings, ceramic tile, insulation, drywall, acoustical wall panels, carpet and resilient flooring.

Palmer Electric Co. Opens Jacksonville Office

Winter Park, Fla.-based Palmer Electric Co. opened a residential division office in Jacksonville, Fla. The Jacksonville office employs a support and field staff of nine. Last fall, the company opened an office in Lakeland, Fla., to serve Polk and Hillsborough counties.

Click here for more Industry News >>