Water main break causes major damage. Its a headline thats becoming more common as an aging infrastructure begins to reveal its weaknesses and failures. University of Texas at Arlington civil engineering Professor Ali Abolmaali is investigating methods he believes will lead to design standards that will prevent failures in future underground installations.
Dr. Abolmaali received a $100,000 research gift and $50,000 from the Texas Research Incentive Program to develop nonlinear fracture and plasticity-based, 3-D finite element algorithms or formulas that will determine the structural behavior of several types of underground pipes and culverts. Older designs were based on two-dimensional representations, he said. These provided only approximations of real conditions and behaviors, so not all possible factors were considered.
These approximations resulted in water mains and culverts that were often over designed or under designed. We can see the results of some failures, said Dr. Abolmaali, but not all of them. If a system was over designed, it could have already had failures but still function well enough for us not to notice until a major problem arises.
Working in his Structural Simulation Laboratory, Dr. Abolmaali and his assistants a post-doctoral researcher and a graduate student are evaluating properties of different materials and designs. Plastic, concrete and steel all undergo long-term changes to their material properties as results of soil and traffic loads and soil chemistry. The shape of the pipe or culvert circular, elliptical, square, or rectangle also influences its abilities to withstand internal and external pressures.
Also under consideration, how fire affects the structural properties. Though pipes and culverts are normally buried a minimum of two feet below the surface, they are exposed at some point and can be subjected to extreme heat.
Once Dr. Abolmaali and his team complete their simulations, sample tests will be conducted on full-scale sections of pipe and culvert to confirm the findings. The team expects of complete their studies in December of this year. After that, they will submit their recommendations to regulatory agencies and organizations for inclusion in national codes. Dr. Abolmaali is currently a member of the Transportation Research Boards committee for culvert and hydraulic structures.
Keeping Americas infrastructure in good condition will be a costly endeavor. A recent news report stated that the City of Dallas had nearly 2,000 water line breaks over the past year; city officials were expected to approve $127 million to fund needed improvements during the coming year.
June 24, 2010