Researcher Aids Arkansas Highway Projects Through Subsurface Analysis

Source: Researcher Aids Arkansas Highway Projects Through Subsurface Analysis | University of Arkansas FAYETTEVILLE, Ark. – A University of Arkansas geotechnical engineer is collaborating with the Arkansas Department of Transportation to map subsurface conditions before road construction begins to identify issues early and help keep highway construction projects on track and on budget. Clint Wood, a civil engineering associate professor and geotechnical engineer, creates profiles of subsurface conditions and soil composition by sending stress waves into the ground and measuring their response at the surface. The non-invasive technology is similar to how ultrasound imaging works on the human body. The technology provides important information for highway designers and construction contractors, who’ve had to rely on imperfect methods for determining subsurface conditions, such as exploratory drilling, a strategy that can miss changes between limited drilling locations. Wood compares designing based on limited exploratory drilling to navigating with an incomplete map. The research is conducted for and in conjunction with the Arkansas Department of Transportation. With an additional $115,318 grant, the transportation department has provided a total of $561,427 in funding. The work focuses on estimating the depth and stiffness of bedrock for new highway alignments and understanding subsurface conditions that cause slope instability. The latter is especially important for understanding how water moves through a slope. Unexpected changes in bedrock depth near slopes can also create pockets where water collects, which can cause the soil in the slope to become saturated, leading to instability. Projects that encounter these issues can face substantial extra costs and delays while designers and contractors adapt the original plan or have to attempt another repair. Those problems can be avoided, or at least minimized, by better understanding the subsurface conditions through non-invasive testing. LIDAR AND DRONE ACCURACY In a separate project, Wood and several other U of A [...]

Hazardous Waste Enforcement Arkansas Department of Energy and Environment

Source: Hazardous Waste Enforcement: Arkansas Department of Energy and Environment - Division of Environmental Quality and Pulaski County Wastewater Treatment Chemicals Blender/Distributor Enter into Consent Administrative Order | Mitchell, Williams, Selig, Gates The Arkansas Department of Energy and Environment - Division of Environmental Quality (“DEQ”) and Ecotech Enterprises, Inc. (“EEI”) entered into a September 15th Consent Administrative Order (“CAO”) addressing alleged violations of Arkansas Pollution Control and Ecology Commission (“APC&EC”) Regulation No. 23 (Hazardous Waste Regulations). See LIS No. 21-091. EEI is stated to blend, package, manufacture and distribute wastewater treatment chemicals and products for use in industrial and municipal potable water and wastewater treatment facilities at a facility in Pulaski County, Arkansas. DEQ conducted a Complaint Investigation at the EEI facility on July 18, 2018. The CAO provides that DEQ noted several containers of waste that could not be identified by facility personnel. Further, wastewaters generated at the facility were stated to be collected in a 2,870-gallon Equalization Tank (“EQ Tank”), then pumped into 275-gallon containers and transported to a POTW for disposal. The wastewater was stated to not be analyzed prior to shipment off-site. DEQ is stated to have conducted an unannounced sampling event in conjunction with a Compliance Evaluation Inspection (“CEI”) on August 29, 2018, to document potential unidentified hazardous waste streams. The CAO provides that based on the findings of the August 29, 2018, CEI, the following APC&EC alleged violations were identified: Failure to make waste determinations on waste streams located through the facility Failure to make a hazardous waste determination on a referenced waste stream Failure to use manifests in certain instances Failure to obtain an EPA identification number prior to transporting hazardous waste Failure to properly label or mark containers and tanks Failure to mark containers with an accumulation start date Failure to keep [...]

Going Deep to Anchor Pump Stations

Source: Going Deep to Anchor Pump Stations | WaterWorld Prime contractor Lakeshore Engineering used a crane with rigging to lower the Beretta T46 Drilling Rig into the excavation as UMA’s team provided direction. You need to build a stable foundation for improvements to a pump station but you’re located in a five-foot water table within proximity to a creek. How do you keep the foundation from rising? Georgia isn't the only place that struggles with a high water table. California, Arkansas, Texas, Nebraska, and Idaho all have large amount of groundwater. One Georgia county’s engineer chose to pin it down with rock anchors with the help of UMA Geotechnical Construction. Cherokee County Water and Sewerage Authority outsourced this pump station improvement project to Atlanta-based Lakeshore Engineering, a heavy civil contractor that focuses on industrial, municipal, and environmental projects. UMA served as the geotechnical subcontractor. Located within proximity to Blankets Creek in Canton, Georgia, the water table is known to fluctuate. UMA’s sole function was to install a rock anchor system to keep the pump station’s concrete slab pinned down. The components to be built on top of the slab would be a diesel engine-driven centrifugal pump and a concrete cast-in-place emergency storage tank. “The rock anchors are there for when the structure is empty,” explains UMA’s senior engineer and estimating manager Mitch Crayton. “When it’s empty and the groundwater table is above the bottom of the structure, if the rock anchors aren't there, it could push up out of the ground like a boat. These buoyant forces are exactly what the rock anchors are there to resist.” Working Down in the Hole One of the biggest challenges for UMA’s team was working in an excavation that was 23 feet deep and 56 feet wide. Lakeshore Engineering had excavated [...]

New Estimate Makes Groundwater Earth’s Largest Water Reservoir on Land

Source: New Estimate Makes Groundwater – Not Ice Sheets – Earth’s Largest Water Reservoir on Land – Leak Herald Hot springs, which can source deep groundwater, are one of the places on the surface where there is evidence of rainwater circulating to depths of two kilometers and deeper. In the states, the top places for finding groundwater are Mississippi, Kansas, Arkansas, Nebraska, and South Dakota. New research doubles volume of salty water two to 10 kilometers beneath the surface that could store waste fluids, sequester carbon, and direct our search for extraterrestrial life. New research more than doubles the estimated volume of ancient, salty groundwater stored deep within Earth’s crust. Around 24 million cubic kilometers (5.8 cubic miles) of groundwater reside within the top two kilometers (1.2 miles) of Earth’s crust. This shallow groundwater is what we use for drinking and irrigation, and it’s mostly freshwater. But below that are vast reservoirs of brine, some of it hundreds of millions to more than a billion years old, locked away in the rocks. The question was: How much is there? A new study estimates there are around 20 million cubic kilometers of deep groundwater, or enough to fill around 4,800 Grand Canyons. Combined with previous estimates of shallower groundwater, the new research finds underground water is the largest reservoir of water on land, measuring 44 million cubic kilometers and surpassing the volume of Earth’s ice sheets. “This estimate expands our conceptual and practical understanding of the amount of water that Earth holds, and it adds a whole different dimension to the hydrologic cycle,” said Grant Ferguson, a hydrogeologist at the University of Saskatchewan who was lead author of the new study in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences. [...]

Informed Streets Pavement Management Solution

Source: Horrocks' Informed Streets Pavement Management Solution Road maintenance is an essential component of city infrastructure. However, deciding what needs to be fixed and when is often a subject of debate. That's where Horrocks' new pavement management system comes it. Using data-driven analysis, it takes some of the guesswork out of the entire process making road maintenance more cost-effective. This will be an exceptionally great tool for cities like Anchorage, Atlanta, Boulder, Chicago, Indianapolis, Little Rock, Los Angeles, San Francisco, New York, and Phoenix. Informed Streets for Pavement Management Horrocks’ new pavement management system has been dubbed Informed Streets. This is simply because it helps create road maintenance schedules, allowing our clients to maximize their budgets by applying the right treatment to the right road at the right time. This system assesses existing pavement conditions and uses predictive models to develop unique, data-driven management plans that optimize costs and upkeep. These plans are created through the following four stages: 1. Initial Assessment and Survey Horrocks’ mobile LiDAR unit during initial survey In the initial phase of service, Horrocks’ in-house survey crews complete a thorough survey and pavement assessment of the roadways. This is done using a truck-mounted Light Detection and Ranging (LiDAR) unit to assess the pavement by collecting one million survey-grade points every second. Our experts then use this data to develop a baseline for a pavement management plan by providing one of two pavement ratings, depending on our client’s needs: the Pavement Surface Evaluation and Rating (PASER) or Pavement Condition Index (PCI). 2. Data Analysis and Planning Once the pavement rating is complete, an online platform is set up for our client, which includes the Informed Streets3D Viewer. Horrocks’ Informed Streets 3D Viewer integrates GIS systems, LiDAR point clouds, and photography in one robust platform that allows for [...]

California Issues Maps of Earthquake Faults to Avoid ‘Potentially Devastating’ Damage to New Buildings

Source: State Issues Maps of Earthquake Faults to Avoid 'Potentially Devastating' Damage to New Buildings - Times of San Diego The Rose Canyon Fault system. Courtesy County News Center Maps released Thursday of earthquake-prone areas are intended to ensure new construction in San Diego does not take place atop dangerous quake faults. Developed by the California Geological Survey, the regulatory Alquist-Priolo Earthquake Fault Zone maps detail where local governments must require site-specific geologic and engineering studies for proposed developments to ensure this hazard is identified and avoided. Generally, new construction for human occupancy must be set back 50 feet from the active surface trace to avoid faults that may break the surface. “Surface fault rupture is the easiest earthquake-related hazard to avoid because you can see the evidence of where it has occurred,” said Steve Bohlen, acting state geologist and head of CGS. “Surface fault rupture means that one side of a fault is moving either vertically or horizontally in relation to the other side. The deformation that movement causes is potentially devastating to buildings and infrastructure.” Two maps of revised Earthquake Fault Zones have been prepared for the Rose Canyon Fault where it comes onshore in Coronado, traversing the San Diego area to the northwest and going back offshore near La Jolla. Each of the maps covers a roughly 60-square-mile quadrangle of territory. The Alquist-Priolo Act was passed into law following the 1971 magnitude 6.6 San Fernando earthquake, which caused extensive surface ruptures that damaged buildings. Not every large earthquake, though, causes surface fault rupture. For example: the Loma Prieta Earthquake of 1989 devastated the Bay Area without breaking the surface. However, the 1992 Landers Earthquake in San Bernardino County caused surface ruptures along 50 miles, with displacements ranging from one inch to 20 feet. “Since the [...]

Dynamic behaviors of wind turbines under wind and earthquake excitations

Source: Dynamic behaviors of wind turbines under wind and earthquake excitations: Journal of Renewable and Sustainable Energy: Vol 13, No 4 Source: How Do Wind Turbines Respond to Winds, Ground Motion During Earthquakes? - AIP Publishing LLC A new study investigates the combined effect of wind and earthquake forces to assess the dynamic behavior of wind turbines. The demand for renewable energy is nowadays at its peak. Wind power is a great source of clean energy and is harvested via wind farms placed in numerous regions across the world. This has led to some winds farms being established in earthquake-prone regions making it important to assess the combined excitation under wind and earthquake forces. In the US, these wind farms are most commonly seen in Alaska, Arkansas, California, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming. The study, recently published in the Journal of Renewable and Sustainable Energy, aims at establishing a numerical model that will integrates both seismic, wind, and operation forces of wind turbines to evaluate the performance of the wind turbines. This is referred to as the "fully coupled model". Such models have been tested before but the research team emphasizes that a solid interpretation of the results is still missing. The authors studied a 5MW wind turbine subjected to a combination of wind load and input ground motion with the latter being retrieved from a list of earthquake records. The study provides some interesting findings. The results from the sophisticated numerical models suggest that the wind that acts as a dynamic load for the wind turbine also exerts a damping effect on the response of the structure. In particular, when shaking is strong, the energy absorbed due to the aerodynamic damping is higher than the actual wind loading generates hence, the [...]

Soil Nail Walls Design and Construction

Source: Soil Nail Walls - Design and Construction -NEW (7003IW2022) INSTRUCTOR:  Naresh Samtani, Ph.D., P.E., D.GE, F.ASCE Participants will have access to the virtual workshop video archives and materials for 60 days from the start day of the workshop. Virtual Workshop Brief Using a collaborative and interactive learning approach, this virtual workshop will help you understand the design and construction aspects for soil nail walls. You will learn newer design approaches based on the LRFD platform that is the basis for guidelines for soil nail walls by the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). The workshop will help you assimilate the design and construction aspects through active participation by frequent interactions throughout the workshop and real-time expert feedback. The interactions will facilitate a better understanding of the nuances of the newer design principles which would help you avoid costly design errors in real-world projects. In between the two live sessions, attendees will independently work on an application (e.g., exercises) or a reflection (e.g., reading) assignment. Learning Outcomes Upon completion of this course, you will be able to: Explain the terminology for soil nail walls Explain design of soil nail walls using principles of limit state design Explain the essential elements of construction Recognize construction procedures and influence on wall design and performance Explain the importance and concepts of nail testing Identify necessary characteristics of software tools Explain corrosion considerations Discuss facing (shotcrete) analysis Identify the necessary information on plans and specifications Benefits for Participants Become familiar with the latest limit state design approaches and standards for soil nail walls Avoid common pitfalls and costly errors in analysis and design Be able to categorize and streamline limit state evaluation Recognize the importance of considering construction as part of overall design process Assessment of [...]

UD researchers study climate change impacts on soils at military installations

Source: The Ground Underfoot - Civil and Environmental Engineering UD researchers study climate change impacts on soils at military installations We walk over it, drive over it and build on it. Yet, it is probably safe to say, most of us rarely think about the ground beneath our feet. Underneath the grass, concrete, asphalt and other materials in our built environment, however, soil provides structure and stability for what lies above. The United States military wants to understand the role that climate impacts, such as flooding, storm surge or sea level rise, will have on soils at its coastal military bases and facilities, which are critical to national security. Soil conditions can affect the integrity of the ground underpinning buildings, roads, bridges and more. For example, if a soil’s pH were to rise significantly, due to increased salt content-containing ions such as sodium from storm surge, it could create saline conditions that could hamper the ground’s ability to support this necessary infrastructure. Understanding these threats will enable faster and more accurate routing and maneuverability for U.S. forces. The Delaware Environmental Institute (DENIN) is collaborating with the Engineer Research and Development Center (ERDC) of the U.S. Army Corps of Engineers and Louisiana State University to understand how vulnerable military installations along coasts may be affected by soil changes due to sea level rise and coastal flooding. DENIN has received $3.79 million in first- and second-year funding from the U.S. Department of Defense to start this work, and is eligible for an additional $3.82 million in continued funding over the following two years. Led by DENIN Director Don Sparks, Unidel S. Hallock du Pont Chair of Soil and Environmental Chemistry in UD’s Department of Plant and Soil Sciences, the UD effort includes interdisciplinary collaboration with Yan Jin, Edward F. and Elizabeth Goodman Rosenberg Professor [...]

Parameters Variation Model Customization and Sensitivity Analyses

Source: Parameters Variation: Model Customization and Sensitivity Analyses Parameters Variation Model Customization and Sensitivity Analyses A well-known engineering challenge in the framework of finite element (FE) analysis-based design is the large number of input factors involved in geotechnical computational models. There is always a significant amount of uncertainties associated with the properties of geomaterials, being naturally highly heterogeneous materials. In the context of model calibration and validation, conducting a sensitivity analysis is very important. This can determine the key factors which govern the system and efficiently characterize the geotechnical variability for any considered design problem.   Powerful mechanisms for the consideration of parameter variation are also very interesting for speeding up FE model creation and automating results in post-processing. These are also quite useful in reducing model definition for specific types of engineering problems (excavation wall of a specific type under simple ground conditions, simple tunnel shape in uniform rock mass, etc.) to a limited number of parameters that can be inputted in a text file or Microsoft Excel spreadsheet without expert knowledge of the PLAXIS user interface and different modeling techniques and FE know-how. The sensitivity analysis and parameter variation tool in PLAXIS A sensitivity analysis determines how different values of an independent variable affect a particular dependent variable under a given set of assumptions. In other words, sensitivity analyses study how various sources of uncertainty in a mathematical model contribute to the model's overall uncertainty. The Sensitivity Analysis and Parameter Variation tool (see Figure 1) can be used to evaluate the influence of model parameters on calculation results for any particular PLAXIS FE model: The Select Parameters tab sheet will first provide information about all the parameters that can be changed to perform the sensitivity analysis. Available parameters include most model parameters of the data sets for soil and [...]

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