City, UTA Engineers Use High-Tech Tools to Evaluate Sewer Pipelines
By UT Arlington University Communications
Posted on December 01, 2015, December 01, 2015

 Tools to Evaluate Sewer Pipelines

After decades of ferrying water and wastewater, drought, floods and changing soil conditions, sewer lines can begin to crack and fail. This happens across the country and Arlington is no exception.

Replacing them all would cost millions. But leading civil engineers from The University of Texas at Arlington's Center for Structural Engineering Research and Simulation have a more efficient, cost-effective solution. They'll use a novel combination of robotic laser equipment and sonar to pinpoint trouble spots in 47 miles of large diameter city pipelines and prioritize which should be mended or replaced first.

"We'll make recommendations for what to do based on where the robots and sonar detects anomalies within the pipes," said Ali Abolmaali, chair of the UTA Civil Engineering Department and director of the Center. "This research could provide a blueprint for other cities to copy."

UTA engineers will complete the work under a three-year, $882,000 contract approved by the Arlington City Council in November. Abolmaali leads the UTA team, which also includes Yeonho Park, a UTA civil engineering post-doctoral fellow, and Mohamad Razavi and Mohsen Shahandashti, senior lecturers in civil engineering. They will evaluate all sewer pipes with a 24-inch or greater circumference and, in a second phase, will recommend a new, more sustainable and resilient system of fiber-reinforced pipes for the future.

"Dr. Abolmaali and his team have the expertise to do this, and we're excited to partner with them," said Buzz Pishkur, the city's water utilities director. "Had we gone out to the market to have the same work done, it would have cost more than $2 million."

Abolmaali is UTA's Tseng Huang Endowed Professor of Civil Engineering and a recognized authority in sustainable infrastructure and pipeline. He has developed two new international standards for synthetic fiber and steel fiber-reinforced concrete culverts, storm drains and sewer pipe, and he has influenced design methods for both rigid and flexible piping systems.

ASTM International, formerly the American Society for Testing and Materials, recently honored Abolmaali as the winner of the organization's prestigious 2015 Merlin G. Spangler Award for his technical contributions.

Among his current projects is research funded through a $1 million Tarrant Regional Water District grant to simulate the behavior and response of pipe-soil interaction that will surround the massive, 150-mile Integrated Pipeline Project from Lake Benbrook to Lake Palestine in East Texas.

For the Arlington sewer system project, UTA researchers will begin evaluating underground pipes using a small robot on wheels that is armed with a laser and video camera. The laser and video camera are used to measure and record images of internal defects that can cause cracks, delamination and other failure criteria.

The team will use a separate sonar profiling system to analyze pipe walls beneath the water line with a technique similar to a medical MRI.

Once a weakness is discovered, a joint university-city team will dig down to extract a segment of the pipe. Researchers will then analyze the pipe sample in the laboratory by using analytic methods to determine its current condition and remaining life.

The information will provide city staff and elected officials valuable information to determine maintenance costs now and needed capital replacement costs for the future.

"The evaluation allows us to make more informed decisions about infrastructure replacement. That could lead to fewer rate hikes and better use of our capital money," Pishkur said. "We can pinpoint where to spend the money at a lower cost to residents and with the least amount of inconvenience.

"Planning for pipe replacement is better than doing it when disaster hits and there's significant damage to streets, lawns and structures."

Pishkur noted that even though the city sewer system is relatively young compared with many around the country, last spring's heavy rains took a toll on some of Arlington's pipes.

"We had some significant wall erosion in spots; one caused a collapse," Pishkur said. "The technology is available today that could give us a good picture of what's going on in those pipes. This refined understanding will then allow us to optimize the operation and dependability of our sewer system."

Khosrow Behbehani, dean of the College of Engineering, said Abolmaali's work exemplifies University research that is creating sustainable urban communities as outlined in the Strategic Plan 2020: Bold Solutions | Global Impact and has huge impact for Texas, in particular.

"Dr. Abolmaali has contacts all over the state," Behbehani said. "This fits in with so many goals of the Texas Water Development Board. Knowing the condition of infrastructure buried in the ground is invaluable information for engineers and elected officials."

Put Technology to Work
Headlines, News, UT Arlington, Water Utilities