A group of civil engineering students and professors are trying to decide whether Louisiana bridges are safe.
Five Ph.D students, two visiting scholars and one master’s student completed a two-year study last month that tested whether the use of intermediate diaphragms on bridges weakens them.
Intermediate diaphragms are beams built perpendicular to the flow of traffic that connect the gutters built parallel to the traffic flow.
The diaphragms absorb the energy cars transfer to the sides of a bridge on impact by either transferring the energy to other beams or allowing only either the car or the bridge to absorb the energy.
Using intermediate diaphragms is controversial, said civil engineering professor Steve Cai.
“Some say that they cause more harm than good,” Cai said.
“Texas, Florida and a few other states have canceled the use of intermediate diaphragms on prestressed concrete bridges, but Louisiana still allows it,” said Marcio Aravjo, civil engineering Ph.D. candidate.
According to the American Society of Civil Engineers, there are prestressed concrete bridges of many types across the United States, and they range from simple span bridges to some of the largest projects ever built.
The Board of Regents gave the group a $200,000 grant to work with the Louisiana Transportation Research Center on the project.
Cai led the team of engineers in the Hooper Road bridge’s testing.
“This bridge was selected because it’s a good representation of the majority of bridges in Louisiana, and it was close by,” Aravjo said.
The group completed the two-year study, which was mostly computer analysis, with a field test.
“The field test were meant to verify some of the computer analysis we did,” Aravjo said.
But before the field test, everyone who participated in the test went through months of training to learn how to use the $150,000 equipment the Civil Engineering Department purchased.
“We compared analysis of different lengths of bridges, angles of the road and different types of gutters,” Aravjo said.
The group passed a truck over the bridge and gathered information through the instruments they installed on the gutters under the bridge.
“Every day we relocated the instruments so we would get different results,” Aravjo said.
Aravjo and Cai both said the final results of the project have not yet been analyzed, but Aravjo said the test results were “pretty much what we were anticipating.”
Cai said they hope to release the results by the end of July.
 
Contact Elizabeth Miller at [email protected]