Presented: June 3rd, 10:00 AM Central Time
Speaker: Dr. Anand J. Puppala, Texas A&M University
This presentation describes key research works on expansive soils, the methods employed to characterize them, and fallacies in the current characterization of expansive soils. Novel swell characterization models that account for hydro, chemical, and mechanical behaviors of soils are introduced and used in various case studies to improve expansive soil stabilization practices. An innovative design method for successful stabilization of expansive soil is introduced in one case study which incorporated both basic clay mineralogy and unsaturated soil behaviors, as well as performance-based durability studies. Sulfate soil stabilization works on medium-to-high sulfate soils are presented in another case study. The last case study involving steep earthen embankment built with expansive clayey soils and experiencing recurring surficial slope failures and maintenance issues is presented along with forensic studies explaining the causes of slope failures. All case studies reveal the need for understanding of soil chemistry, including clay mineralogy and sulfate screening studies, to improve the current field stabilization and infrastructure design on expansive soils. The last section of the talk focuses on recent innovations for better health monitoring and management of civil infrastructure built on expansive soils using unmanned aerial vehicle (UAV) platforms and visualization tools, which will be valuable in validating the application of new materials in infrastructure design and construction processes as well as for health monitoring and asset management practices.
Dr. Anand J. Puppala currently serves as A. P. Wiley and Florence Chair of Zachry Civil and Environmental Engineering at Texas A&M University and is also an Associate Director of Center for Infrastructure Renewal (CIR), both appointments started since September, 2019. He served as Associate Dean - Research in College of Engineering for 7+ years and was a Distinguished Scholar Professor in the Civil Engineering department at the University of Texas at Arlington (UTA) in Texas, USA since 1996 Dr. Puppala is the current chair of Soil Mechanics section (AFS00) of the Transportation Research Board (TRB) and is a member of Design and Construction group of TRB. He also chaired American Society of Civil Engineers (ASCE)’s Geotechnical Institute’s (GI) “Engineering Geology and Site Characterization” committee and TRB committee on ‘Soil and Rock Instrumentation’. Dr. Puppala also served as President of United States Universities Council on Geotechnical Education and Research (USUCGER) from 2007-2009.
Dr. Puppala has been conducting research on stabilization of expansive soils, UAVs for infrastructure monitoring studies and asset management studies, dam safety and embankments slope studies, in situ intrusive methods for site characterization, infrastructure resilience and material characterization studies. Dr. Puppala has been a recipient of several major research grants totaling over 22+ Millions of dollars from federal, state, and local government agencies. Dr. Puppala is the current director of NSF’s Industry University Co-operative Research Center (IUCRC) site on Composites in Civil Infrastructure (CICI) at TAMU. He has been serving as program director of TRANSET, a University Transportation Center (UTC) based in LSU. Dr. Puppala’s research scholarly record included 480+ publications including 200+ Journals and he has also edited seven special publications. He has supervised 35 Doctoral and 52 Masters’ thesis students and is currently advising 11 doctoral students and two postdoctoral fellows. Dr. Puppala is an editorial member for several major journals in Civil Engineering including ASCE Journal of Geotechnical and Geoenvironmental Engineering, Journal of Materials, ASTM Geotechnical Testing Journal and edited several books including seven ASCE Special Publications. He has given several Keynote and invited talks all over the World including a prestigious ASCE GI Peck talk at 2020 GeoCongress Meeting held at Minneapolis, Minnesota.
Question: Could you please tell me some improvements other than using piles, mixing with sand, lime or bentonite? Could you give us some suggestions to stabilize this kind of soil (expansive soils)?
Answer: We are working with geosynthetics (wicking geotextiles and geocells...some papers published in TRB and other places), Geopolymers (on-going) and GGBFS (works are done in Singapore and others places....we are also looking at polymer emulsions and nanosilica for some on-going works for US Army Corps and UTCs. Suggestion is do the lab design with performance based durability study before you implement in the practice.
Question: Is it envisaged in the future to use drones to determine the exact depth of the swelling soil layer?
Answer: Imagery mostly surficial....spectral cameras (multi-spectral and hyperspectral cameras) can identify clay minerals but they are surficial at best...if there is a cut exposes soils at different depths, you can identify the clay minerals...right now from top down, difficult to identify except for an inch. or two.
Presented: April 19th, 11:00 AM Central Time
Speaker: Dr. John W. van de Lindt, Colorado State University
The study of community resilience requires modeling of each sector across a community, but the sectors must interact, often representing contributions from different scientific disciplines. This type of complex modeling requires the analyst to not only have an understanding of disciplines outside of engineering but to actively work and engage with key experts in sociology/planning and economics. This presentation began with an overview of the Center for Risk-Based Community Resilience Planning’s approach to merge engineering, social science/planning, and economics to form the Interdependent Networked Community Resilience Modeling Environment (IN-CORE). This includes learning from an interdisciplinary longitudinal field study beginning in 2016 to present for flooding in Lumberton, NC, including challenges posed by a second hurricane and the pandemic on data collection and interpretation. The presentation closed with an illustrative example application of a community planning for tornado hazard and an example of resilience-informed policy guidance.
Dr. John W. van de Lindt is the Harold H. Short Endowed Chair Professor in the Department of Civil and Environmental Engineering at Colorado State University. Over the last two decades van de Lindt’s research program has focused on performance-based engineering and test bed applications of building and other systems for earthquakes, hurricanes, tsunamis, tornadoes and floods. Professor van de Lindt is the Co-director for the National Institute of Standards and Technology-funded Center of Excellence (COE) for Risk-Based Community Resilience Planning headquartered at Colorado State University entering its seventh year. He has published more than 400 technical articles and reports including more than 200 journal papers, and currently serves as the Editor-in-Chief for the ASCE Journal of Structural Engineering.
Presented: April 3rd, 2020, 2:00 PM Central Time at Butler-Carlton Hall
Speaker: Dr. Yan Xiao, University of Illinois at Urbana-Champaign
Columns are the most important structural elements in buildings and bridges to transfer the gravity loads to foundation and to resist any lateral loads. Particularly in the case of earthquakes or other accidental events, structural columns need to be designed to resist strong lateral loading effects while maintaining a sound support of the gravity load. Approximately from the mid-fifties of last century, experimental studies on structural columns subjected to the lateral load dominant loading condition became one of the most important research areas. This presentation reviews the development and evolution of the testing methods for experimentally studying behaviors of structural columns. Following the needs of testing larger scale columns, the axial loading becomes a challenge. The presentation discusses the problems in conventional methods for axial loading in seismic simulation tests. It was from the examination of the problems in existing axial loading methods that the presenter has conceived and developed a new type of large-scale structural testing system MUST (Multiple Usage Structural Testing equipment). The new equipment has the advantages of maintaining the axial loading to be perpendicular to the lateral loading and the actual forces applied to the model specimen can be directly monitored, thus overcoming the problems in conventional testing systems. The first MUST system (2d-MUST, shown in Fig.1a) was installed at the Hunan University, which possesses the vertical loading capacity of 20000kN and the lateral loading capacity of 4000kN. The second MUST system (3d-MUST, Fig1b) completed at Nanjing Tech Univ. has capacities of 10000kN in vertical, and 3000kN in two horizontal directions), capable for three directional pseudo-dynamic simulation. The presentation also discusses the testing results of eight full-scale large-size wide-flange steel columns using the 2d-MUST equipment.
Dr. Y. Xiao is a Changjiang/Qianren Distinguished Professor and serves as the Program Director for Energy, Environment and Infrastructure Sciences, in the Zhejiang University – University of Illinois at Urbana-Champaign Joint Institute (ZJUI), Zhejiang University. Dr. Xiao received his Bachelor of Engineering degree from the Tianjin University, China, in 1982, his Master and Doctor of Engineering degrees from the Kyushu University, Japan, in 1986 and 1989, respectively. Prof. Xiao’s professional and academic experiences include assistant research scientist at University of California, San Diego, tenure-track and tenured full professor at the University of Southern California. He was previously the dean of Civil Engineering College at Nanjing Tech University (2015-2018), and the Hunan University (2006-2015). He serves as the associate editors for the ASCE Journal of Structural Engineering, Journal of Bridge Engineering, and editorial board member of the Journal of Constructional Steel Research. He is an elected fellow of the American Society of Civil Engineers (ASCE) and American Concrete Institute (ACI). He is a registered Professional Engineer in California.
Prof. Xiao’s scholarly contributions are in areas related to confined concrete, hybrid and composite structures, applications of advanced composites, retrofit/repair of structures, impact effects, and large-scale experimentation, etc. His recent research and industrial efforts are focused on developing modern bamboo structures for buildings and bridges with the goal of promoting environmentally and eco-friendly construction. He holds the award winning technology of GluBam.
Presented: December 4th, 2019, 2:30 PM Central Time at 121 Butler-Carlton Hall
Speaker: Dr. Baoshan Huang, University of Tennessee-Knoxville
Asphalt pavements covers over 93 percent of the paved roads in the United States. The use of recycled asphalt into pavement maintenance and construction has been a common practice. However the lack of understanding of the interaction between recycled and virgin asphalt poses a change on the efficient use of recycled asphalt, and often causes pavement premature failures. The present study addressed some fundamental aspects associated with the beneficial use of recycled asphalt into asphalt paving mixtures: 1) how much recycled asphalt can be mobilized into a uniform asphalt coating in the mixture? and 2) will the mobilized old asphalt co-mingle with virgin asphalt to form a homogeneous material? Analytical chemical procedure and fluorescence microscopy (FM), and molecular dynamics simulation have been utilized for the analyses. The results have provided better understandings on the homogenization process between the recycled and virgin asphalt; thus provide better guidance to efficient use of recycled asphalt pavements.
Baoshan Huang, Ph.D.,P.E, is the Edwin G. Burdette Professor of Civil Engineering at the University of Tennessee-Knoxville, where he has been employed since January 2002. He earned his Bachelor's and Master's Degrees at Tongji University in China and a Ph.D. at Louisiana State University. His areas of research include transportation infrastructure materials, pavement engineering, geotechnical engineering, and infrastructural asset management. Over the last fifteen years of his professional career, Dr. Huang has secured over ten million dollars of research funding to support his research activities. He has been actively involved in many professional committees, including the Transportation Research Board (TRB), Association of Asphalt Paving Technologists (AAPT), American Society of Civil Engineers (ASCE), and the International Society of Asphalt Pavement (ISAP). He was the chair of the ASCE Bituminous Materials Committee (BMC) during 2010-2012, and has been associate editors for the ASCE Journal of Materials in Civil Engineering, Journal of Transportation Engineering - Part B: Pavements, Journal of Cleaner Production, and serves in editorial boards for several international journals. Dr. Huang has published over 180 (SCI Indexed) journal papers and holds five US patents (one pending), one International patent, and three Chinese patents (two pending) on innovative infrastructure materials design and characterization.