Tools Needed to Bounce Back After the Storm

Coastal storms have raked North Carolina, with intense winds demolishing buildings and ripping apart infrastructure. They also have swamped the state, with torrential rains forcing residents to flee for higher ground and leaving homes uninhabitable. NC State researchers are studying ways to design coastal communities—through planning and construction—to be more resilient in future storms. "You know you're going to take a hit," Dr. Margery Overton says. "What we want to know is how well you can handle it and recover."

A professor in the Department of Civil, Construction and Environmental Engineering (CCEE), Overton is leading a team of NC State researchers addressing engineering challenges for a Department of Homeland Security (DHS) center that focuses on natural disasters and emergency management. With 20 years of experience in coastal erosion research, Overton is studying how landforms and structures change before, during, and after coastal storms. She cites Hurricane Isabel, which chewed up the Outer Banks in 2003, creating a new inlet and severing the main road on Hatteras Island. Overton uses different models to measure how variations in storm surge and waves affect the movement of sediment, which could give communities an idea of how much beach and dune erosion to expect during storms. "The more aware you are of the potential for damage, the better you can prepare," she says. "You can take preventive steps or identify ways to quickly recover after a storm."

Research by CCEE professors John Baugh, Downey Brill, Mo Gabr, George List, Ranji Ranjithan, and Rudolf Seracino involves using sensors to monitor the structural integrity of bridges, levees, and other infrastructure and to determine when they have been damaged beyond repair; developing innovative designs and retrofits for flood walls; and creating integrated computer models for in-depth analysis of water and transportation systems and improved disaster preparedness. Overton says the team hopes to develop various tools that can be used by communities to become more resilient. "Comprehensive systems models can be incorporated to identify weak links and ways to establish redundancies in critical systems," she says. "We could potentially identify specific infrastructure that can be designed to higher standards and either rebuilt or relocated."

Design standards are a key element in recovering from coastal storms and other natural disasters, says Dr. Billy Edge, a CCEE professor and director of the Coastal Processes and Engineering Program at the UNC Coastal Studies Institute in Manteo. Edge is a veteran of disaster zones, having led teams of engineers into the aftermath of the Indonesia tsunami, Hurricane Katrina, and last spring's earthquake in Chile. "Too many areas are unprepared," he says. "People just don't recognize the fragility and the severity of their environments." Normal beach erosion, for example, routinely claims houses on the Outer Banks, and coastal storms place significantly higher stresses on area buildings and infrastructure. "The more intense hurricanes we've seen in recent years have really set a new bar for design to withstand such storms," Edge says.

Devastation by Hurricane Ike two years ago forced the Galveston, Texas, area to build to higher standards—literally. Edge visited the region shortly after the storm to examine damage to buildings, roads, bridges, and the marine infrastructure. He returned last year to measure the rebuilding process and the impact of coastal management plans. The information he collected is helping him and others create statistical models the Federal Emergency Management Agency (FEMA) is using to map flood zones along the Texas and Louisiana coasts. Some Galveston homes now are built more than 20 feet off the ground to get out of the flood zone, and their utilities likewise will need to be elevated and protected from storms. "We need structures at the coast that are sustainable," he says, "and it's my job to find ways to design them."

Dr. Dave Tilotta is trying to find ways to make building materials more storm-proof. An associate professor and extension specialist in the Department of Forest Biomaterials, Tilotta is NC State's point man for the DHS' Resilient Home Program. The effort came about after Hurricane Katrina, when officials realized there was no single place for homeowners whose houses had been damaged in a natural disaster to seek information. Tilotta's team worked with program members at Savannah River National Laboratory, the U.S. Army Corps of Engineers, and Clemson University to create YouTube videos and other means to disseminate information on issues like mold mitigation and ways to retrofit homes. They also developed performance-based guidelines to encourage construction of buildings to better withstand high winds.

"The best way for a community to recover from a natural disaster is to get people back into their homes as quickly as possible."

The Resilient Home Program is now ramping up research efforts, such as determining how resistant building materials are to floodwaters. "FEMA provides guidance on when materials should be considered too damaged for use, but there's no science behind them," Tilotta says. His team dunks flooring into specially built flood-simulation tanks in Hodges Laboratory that contain river water or saltwater. After soaking the boards for up to a couple of weeks and then drying them out, they put the materials through a battery of tests to see how well they meet performance standards like weight-bearing capacity. Eventually, Tilotta says, they will test wall studs and other materials as well. "The best way for a community to recover from a natural disaster is to get people back into their homes as quickly as possible," he says. "Our research and education efforts are designed with that goal in mind."

 

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Dr. Mo Gabr (left) and graduate student Cary Caruso (foreground) demonstrate the use of the newly developed scour probe to Dr. Margery Overton in preparation for field work to study the scourability of barrier island dune systems on North Carolina's Outer Banks.

Dr. Billy Edge leads research regarding disaster zone recovery and sustainable engineering practices in disaster environments.

Dr. Dave Tilotta (left) and Tyler Strayhorn, an M.S. candidate in Forest Biomaterials, use flood-simulation tanks to test building material resiliency to river water and sea water.