Research
in Civil and
Environmental Engineering
Research Centers and Facilities
- UNR-Network for Earthquake Engineering Simulation (NEES)
- Bridge Research and Information Center
- Transportation Technology Transfer Center
- Western
Regional Superpave Center
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Earthquake & Structural | Geotechnical | Pavements/Materials | Transportation | Environmental
Structural and Earthquake Engineering Research
Contact: Prof. Ian Buckle
Also visit: UNR NEES and BRIC
The graduate program in Structural and Earthquake Engineering emphasizes the behavior of reinforced, prestressed, and steel structures under gravity and extreme loads such as earthquakes. The CEE Department hosts a state-of-the-art UNR NEES research laboratory. The Laboratory is equipped with three identical, biaxial, 50-ton shake tables, capable of being relocated on the Laboratory's tie-down strong floor. These tables are 4.25 m (14 ft) square and may carry up to a 445 kN (50-ton) payload at 1g acceleration. They may carry higher loads at lower accelerations, provided bearing capacities are not exceeded. Other peak performance characteristics include 1000 mm/sec (40 in/sec) velocity and +300 mm (+12 inches) stroke.
Three banks of blowdown accumulators are used to achieve this performance. Maximum velocity in continuous operation is 625 mm/sec (25 in/sec). The Laboratory also has seven MTS servo-controlled actuators ranging in size from 245 kN @ +75 mm stroke (55 kips @ + 3 in stroke) to 3.1 MN @ +600 mm stroke (700 kips @ + 24 in stroke). These actuators are used for large-scale experiments on structural components that are unsuitable for shake table execution and are mounted directly on the strong floor.
Three high-speed, data acquisition systems from National Instruments, Pacific Instruments and OPTIM Electronics are used for table-mounted and floor-mounted experiments. Total channel capacity is 250-channels, Data is currently archived on a data storage server and backed-up on CD-ROM. An SGI Origin 2200 Server with a library of simulation codes is available for data processing and numerical simulation studies.
The Laboratory was completed in 1992 and expanded to increase the area of the strong floor by 50% in 1999. The 780 m2 (8400 sq ft) precisely leveled strong floor, is a 4-cell box girder with tie-down holes in the upper slab at 600 mm (24-inch) centers. It weighs about 22 MN (5000 kips). To accommodate future needs of unknown shape and form, the facility is modular in design. Reaction buttresses are assembled
from 85 kN (19- kip) concrete blocks, which are stressed together, and to the
floor, in customized configurations. In like manner, the three shake tables are
relocatable into different configurations according to the demand of present
and future needs. Hydraulic pumps are located in a separate pump-house connected
to the Laboratory through large diameter hardlines. Pumping capacity (continuous
rating) is 1566 l/min (415 gpm). Blowdown accumulators lift this rate to 9084
l/min (2400 gpm) on demand, for short periods of time.
Environmental Engineering Research
Contact : Prof. Eric Marchand, Ph. D.
Engineering Approaches for Prevention and Treatment of Acid Mine Drainage
Principal Investigator: Eric Marchand
Summary: Acid Mine Drainage (AMD) is a water quality problem throughout the world that lacks a clear, cost-effective solution. Much of the problem with AMD arises from the microbial mediation of metal releases from mine wastes, creating toxic metal and acid discharges. This project will investigate the role of enhanced heterotrophic microbial growth as an engineering control technique to lower the amount of arsenic released from arsenic bearing minerals at acid mine drainage (AMD) sites and control the arsenic speciation so it is not as mobile in the environment. This strategy will attempt to encourage the growth of microbes that do not produce acid in an effort to adjust the microbial ecology in a beneficial manner, thereby preventing AMD.
Evaluation of the Applicability of Centrate as a Nutrient Supplement to Irrigation Water
Principal Investigator: Eric Marchand
Summary: One effective and cheap mechanism that can prevent the degradation of water and air quality is to limit or reduce the discharge of pollutant streams from engineered processes into the environment. For example, centrate is an undesirable liquid byproduct of wastewater treatment that is high in nitrogen and phosphorus.
The nutrients present in centrate offer a potential benefit of reusing the centrate by blending this waste stream with reuse water to lower the fertilizer demand of irrigation water. This project proposes to reduce waste streams from wastewater treatment and to benefit plants by investigating the chemical composition of centrate and then supplementing irrigation water with low concentrations of centrate.
Assessment and Optimization of Aquifer Recharge and Recovery Systems for the Removal of Trace Organic Contaminants
Principal Investigator: Edward Kolodziej
Summary: Despite the many Aquifer Recharge and Recovery (ARR) systems in operation or planned for water reuse and recovery systems, few ARR systems are specifically designed for active treatment of trace organic contaminants. While natural attenuation is the primary mechanism of contaminant removal in most ARR systems, numerous opportunities exist in ARR systems to improve contaminant removal by optimizing degradation rates in the subsurface. Because hydraulic retention times of weeks to years are typical for ARR systems, relatively inefficient degradation processes that are kinetically slow can potentially be used to obtain near complete removal of contaminants. Infiltration basins, recharge wells, the vadose zone, and the saturated zone all represent potential control points that could be used to engineer ARR systems for optimized contaminant removal.
Engineered ARR systems might be cost-effective alternatives to additional unit operations in WWTPs if rates of natural attenuation in the subsurface could be accelerated by control of the reduction-oxidation state of the ARR system or by infiltrating chemical additives into the ARR system. Using this strategy, it may be possible to shift some of the “burden” of improving water quality from WWTP unit operations to the ARR system. Specifically, engineered treatment in ARR systems might partially replace the need for expensive and complex nanofiltration, reverse osmosis, or ozonation treatment of recharge water. Conceptually, this project regards the ARR system as an extension and integral part of the WWTP treatment train because it can represent additional treatment barriers preventing the occurrence of trace organic contaminants at the point of reuse.
Transport and Transformation of Natural and Synthetic Steroid Hormones at Beef Cattle and Dairy Concentrated Animal Feeding Operations (CAFOs)
Principal Investigator: Edward Kolodziej
Summary: This collaborative project (with UC Berkeley and UC Davis, funded by the EPA STAR program) assesses the occurrence, fate, and transport of synthetic steroid hormones used for beef cattle production and endogenous steroids produced by cattle and cows from concentrated animal feeding operations (CAFOs).
We hypothesize that the most important pathways for steroid releases from CAFOs are the discharge of contaminated stormwater runoff and migration in groundwater recharged through animal waste lagoons and animal feeding areas. The fate of synthetic hormones is being evaluated at research and commercial beef cattle feedlots located in California, Colorado and Iowa.
At the University of Nevada, Reno, methods for the analysis of synthetic steroid hormones are being developed using a sensitive GC/MS/MS analytical method. To quantify the relationship between growth hormone treatment and surface water releases, stormwater runoff samples are being collected at two research feedlots where hormone administration rates and waste handling procedures are rigorously controlled.
Additional insight into steroid hormone fate and transport will be obtained by collecting samples at locations throughout two research feedlots and several full-scale commercial beef cattle CAFOs.
Water Characterization and Sediment Transport Analysis of the Upper Walker River
Principal Investigator: Keith Dennett
Summary: Walker Lake in western Nevada is a desert terminal lake that is some of the little remaining habitat for endangered Lahontan Cutthroat trout. The Walker Lake Basin also is one of Nevada’s most productive agricultural areas, creating conflict between environmental and agricultural uses of the limited water resources of the Walker River. This project attempts to characterize sediment and dissolved salt fluxes through the Walker River basin, as one of the main mechanisms of habitat degradation in Walker Lake is the increasing lake salinity, driven by salts entering the lake via Walker River.
Laboratory experiments in conjunction with field sampling indicate that the West Walker River has approximately twice the dissolved salts when compared to the East Walker River. A comparison between the historical data for the United States Geological Survey (USGS) site at Wabuska, Nevada and CWR #3 in this project indicated that the transport of total dissolved solids (TDS) dropped by approximately 82% corresponding to an 82% reduction in salt flux when compared with historical data gathered in 1995. The observed statistical correlations between analytes studied and flow and the difference in water quality between the east and west forks of the Walker River, indicated a potential for controlling the mass of dissolved salts on the combined Walker River, and an increase in water quality, through flow regulation on the east and west forks of the Walker River.
Geotechnical Engineering Research
The Geotechnical faculty are active in several research programs. The specific research projects in geotechnical engineering vary widely from year to year, but the principal research areas are indicated by the interests of the individual professors as listed in their bio and personal webpage.
Pavements/Materials Engineering Research
Evaluation of Construction Techniques for Longitudinal Joints in HMA Pavements
Hot mixed asphalt (HMA) pavements are normally constructed with multiple passes of the paver. Typically, one lane is laid-down with each pass. Consequently, a longitudinal construction joint is formed between the constructed lanes. A low density at the longitudinal joint would result in water penetrating into the HMA layer and damaging the HMA mix and the supporting layers. The water damage usually causes premature failure of the flexible pavement. One way to avoid such failures is to construct a dense longitudinal joint that would prevent the intrusion of water. The overall objective of this research was to establish the needed knowledge base for the development and implementation of a longitudinal joint specification for the Nevada Department of Transportation (NDOT). A field-testing program was carried out to evaluate the effectiveness of the various joint geometries and compaction techniques in increasing the joint density and providing improved performance.
Design System for HMA Containing a High Percentage of RAP Material
Reclaimed asphalt pavement (RAP) is generated by cold milling, heating/softening and removal of the existing aged asphalt pavement, full depth removal, or plant waste hot mix asphalt (HMA) materials. The interest in the use of RAP has increased dramatically since the recent price increases in crude oil and energy in general. Therefore the use of RAP materials in HMA can be highly beneficial from both the economical and long-term performance aspects if the appropriate testing and analysis procedures are used to design the final mixtures. The overall objective of this research effort is to develop testing and analysis procedures that can be effectively used to evaluate RAP materials and optimize the performance of HMA mixtures containing RAP materials. The research effort will cover the various aspects of the design process starting with the evaluation of the RAP materials (binders and mixtures) through the mix design process and the performance evaluation of the final HMA mixture containing RAP materials.
Warm Mix Asphalts
Asphalt pavements make up 95% of the paved roads in the US. The production and construction of asphalt mixtures are conducted at extremely elevated temperatures which consumes a significant amount of fuel and generates high dust and emissions. Typical asphalt mixtures are produced by heating the aggregates and asphalt binders at 325oF and laying the mix down on the road at 300oF. This process is known as the Hot Mix Asphalt (HMA). The Pavements/Materials Program in the Department of Civil and Environmental Engineering is a member of a national group that is working to develop a technology by which asphalt mixtures can be produced and constructed at lower temperatures. This process is called Warm Mix Asphalt (WMA). The WMA technology is expected to reduce the production temperature to around 250oF and the construction temperature to around 200oF. These reductions in temperatures are expected to reduce CO2, CO, and NOX emissions by some 35%, reduce dust generation by 90%, and reduce fuel usage by around 35%. The overall objective of this research effort is to gain an understanding of the effects of commercially available warm mix additives on the performance of the asphalt binder and mixture and mixture workability. This understanding will allow for optimization of mixture design and construction practices for application of warm mix technology to the field. Optimized practices will be applied in field trials and evaluated/refined through monitoring of pavement performance. Overall the work of the Pavements/Materials Program is expected to generate positive impacts on highway workers safety, the economy, and the environment.
Impact of Hydrated Lime on Performance of Asphalt Mixtures
The purpose of this project is to quantify expected increases in pavement life from adding lime to asphalt, based on extensive laboratory testing of multiple lime-asphalt mixtures. This project differs from previous studies in several respects. First, because lime is used in asphalt primarily for antistripping benefits, previous studies rarely quantify lime’s other performance benefits. Second, because testing is typically performed on only the asphalt mix being considered for a project, and only as necessary to satisfy specifications, typical studies do not capture the full range of failure modes and environmental stresses. Furthermore, once specifications are met, test results are rarely translated into pavement performance characteristics. This project, by contrast, will evaluate five asphalt mixtures with the most widely accepted laboratory tests for the following modes of pavement failure:
- moisture damage
- fatigue cracking
- permanent deformation
- thermal cracking
- oxidative aging
With these tests, the impact of lime and liquid additives on the mechanical properties and performance of HMA mixtures will be estimated, in terms of increases in pavement life. Changes in pavement life and performance will also be translated into changes in the life cycle cost of HMA pavements.
Transportation Engineering Research
- “Feasibility of of Using Video Cameras for Automated Enforcement on Red-light Running and Managed Lanes,” Nevada Department of Transportation (9/1/2008 – 7/31/2009) ($150,000)
- “Feasibility of Implementing an Automated Trucking System along the I-80 Freeway,” Nevada Department of Transportation (9/1/2008 – 1/31/2010)
- "Evaluation of Video Detection Systems and Development of Application Guidelines at Signalized Intersections," Regional Transportation Commission of Southern Nevada and the Nevada Department of Transportation (2/1/2008 – 12/31/2009)
- “Pedestrian Behavior Study at Marked and Unmarked Pedestrian Crosswalks”, Traffic Safety Center, University of California, Berkeley (7/1/2008 – 8/31/2008)
- "Evaluation of Adaptive Signal Control Systems,” Regional Transportation Commission of Southern Nevada (4/1/2008 – 12/31/2008)
- "Nevada Teen Seatbelt Survey," PREUSSER Research Group, Inc (9/1/2007 – 12/31/2008)
- "Development of Surrogates for Crashes," Sponsored by Nevada Department of Transportation, (1/1/2007 – 12/31/2008).
- "SafetyAnalyst Implementation Demonstration," Sponsored by Nevada Department of Transportation, (1/1/2007 – 6/30/2008)
- "Guidelines and Field Implementation of Left-turn Signal Control for the State of Nevada," Sponsored by Nevada Department of Transportation, (1/1/2006 – 12/31/2007).
- "Techniques to Improve Safety and Operations at Signalized Diamond Interchanges in Nevada", Sponsored by Nevada Department of Transportation, (3/1/2006 – 12/31/2007).
- "Development of Roundabout Geometrics Design Guidance", Sponsored by the California Department of Transportation, (1/1/2006 – 6/30/2007)