ASCE has honored the following people with the 2019 Walter L. Huber Civil Engineering
Christopher P. Higgins, Ph.D., A.M.ASCE, for fundamental contributions to advancing the science on the fate and transport of polyfluoroalkyl substances (PFAS) and other emerging contaminants in aquatic and terrestrial systems, which leads to guidelines and models for subsurface remediation.
Higgins has been conducting research on the fate, transport, bioaccumulation, and treatment of poly- and perfluoroalkyl substances (PFAS). PFAS have become one of the most important classes of environmental contaminants in a generation, affecting tens (if not hundreds) of millions of people throughout the United States. Higgins has been filling key data gaps for these compounds, with profound implications on how engineers are managing risks associated with PFAS.
The problems associated with these substances are especially challenging because of the unusual behavior resulting from their oil and water repellency. Some of the PFAS are extremely persistent in the environment, and bioaccumulative. The scientific understanding of the complex behavior is not yet complete enough to apply in the field through directly incorporating to engineering practice. As a leader in the field, Higgins regularly receives inquiries from field engineers managing PFAS-contaminated sites. As one example, in one of the papers from Higgins’ research group, it was suggested that biosparging that occurred at a PFAS-impacted site led to the significant generation of perfluorocarboxylates like PFOA in situ. It is speculated that similar processes happen at other sites. Although he has been approached by consultants throughout the U.S., an environmental consultant in Sweden contacted Higgins in relation to a PFAS plume from an abandoned fire protection training area moving toward a drinking-water body. This consultant was unable to find the information needed to develop an effective remedial strategy and sought to use the information from Higgins’ work to make decisions about site management.
Higgins’ work on plant uptake of PFAS has also been used by a number of state regulators (and federal regulators in the U.S. and Australia) to develop effective PFAS management plans for impacted farms and gardens. His pioneering work is filling the science knowledge gaps that will help develop engineering guidelines to address these types of remediation and human exposure issues.
Sinan Keten, D.Eng., Aff.M.ASCE, for his contributions to our understanding of the mechanical behavior of structural materials and for establishing novel molecular simulation techniques for characterizing the nanomechanics of polymer nanocomposites.
Structural composites blending the best aspects of polymers with carbon-based and cellulose-based fillers are breaking new ground, leading to improved moisture responsiveness, strength, and rheological properties in new load-bearing systems. Keten’s research focuses on the mechanics of these materials starting from the nanoscale. Nanoscale mechanisms of creep, failure, and strength in civil engineering materials is still not fully understood. Development of materials-physics-focused approaches on structural materials such as composites and cementitious materials is central to a safer and more sustainable future.
Keten’s research aids our profession by providing fundamental insights into making structural materials stronger, tougher, and lighter, with inspiration from biological materials, and using computers to guide design. These novel materials systems will continue to impact the rapidly changing civil engineering materials landscape with the advent of large-scale 3D printing.
Given that Keten does fundamental theoretical on materials, translation of his finding to direct civil engineering applications will take time. However, the methods he has developed for materials modeling have been internalized by construction industry suppliers such as the Dow Chemical Company to design novel materials that may range from fiber reinforced composites to structural adhesives. His work on nanocellulose interface characterization and moisture response have been cited by other research groups investigating structural materials such as cement paste, structural wood, and polymer composites.
Dimitrios Lignos, Ph.D., A.M.ASCE, for significant contributions in developing state-of-the-art methods to simulate extreme limit states in steel structures.
Lignos’ development of cutting-edge models for simulating structural deterioration and collapse are possibly the most widely used for seismic collapse simulation. This work is comprehensive, effectively integrating large- and small-scale tests with rigorous computational methods. Through documents that he helped author, his work is being directly applied for performance/collapse assessment of steel buildings. Additionally, his work on composite beam effects and beam-column connections has been included or is being balloted in Eurocode 8 as well as the Canadian Institute of Steel Construction (CISC) Handbook.
As performance-based engineering (specifically earthquake engineering) is mainstreamed into the engineering practice, the necessity for reliable, high-fidelity models for collapse assessment has become extremely critical. As indicated by the support letters, Lignos’ modeling methodology is possibly the most ubiquitous, rigorous, and dominant methodology for this purpose. A consequence of this more accurate and reliable (low-uncertainty) prediction of collapse which directly leads to safer, resilient, and economical buildings – the ultimate goal of the structural engineering profession.
Shaily Mahendra, Ph.D., A.M.ASCE, for pioneering the application of enzyme-nanoparticle vaults in water treatment, significantly contributing to application of molecular biological and stable isotopic diagnostic tools in bioremediation of organic contaminants and advancing our understanding of the impact of nanomaterials on microbial ecosystems.
Mahendra’s research findings support the following recommendations for environmental engineers:
- Many substances appear recalcitrant in the environment but are in fact biodegradable.
- Biodegradation rates must be measured and monitored in the presence of contaminant mixtures under realistic environmental conditions.
- Analyses of biomarker genes are useful in making decisions for monitored natural attenuation or enhanced bioremediation and postremediation monitoring at contaminated groundwater sites.
- The use of pure enzymes instead of whole microbes for biodegradation of water contaminants is more efficient and eliminates public health concerns.
- Biofilms can be protective against nanoparticles, and previous planktonic-based assessments might overestimate nanoparticle-derived toxicity in wastewater, wetlands, and soils.
Mahendra’s research has benefited the civil engineering profession by providing mechanistic and quantitative data needed for
- Changing the industrial and regulatory perception of biodegradability of emerging contaminants like 1,4-dioxane, polyfluoroalkyl substances, nitroaromatics, and bisphenol analogs
- Characterizing biological treatment mechanisms, especially in contaminant mixtures
- Improving genetic and isotopic tools to validate natural or enhanced remediation effectiveness
- Comprehensive understanding of nanomaterial impacts on environmental organisms and ecosystem services.
The Walter L. Huber Civil Engineering Research Prizes are awarded to members of the Society, of any grade, for notable achievements in research related to civil engineering. Preference is given to younger members (generally under 40 years of age) of early accomplishment who can be expected to continue fruitful careers in research.