Source: UNF first in Florida to conduct large-scale l | EurekAlert! Jacksonville, Fla. – University of North Florida researchers will be the first in Florida to conduct large-scale laboratory testing of sinkhole mechanics. Dr. Ryan Shamet, civil engineering assistant professor, was recently awarded a Florida Department of Transportation project grant for “Validation and Update of the Sinkhole Index,” a project that will aim to better understand the potential of sinkhole formation prior to any collapse at the surface. This joint project between UNF and University of Central Florida includes $90,259 for UNF and new equipment coming to UNF labs. The new equipment consists of a large-scale soil box that will allow UNF researchers to recreate and monitor the geotechnical and hydraulic mechanics of sinkholes forming in north and central Florida. The researchers at UNF and UCF will collect data from active sinkhole sites throughout the state and then refine and update analysis techniques for varying geologic conditions or regions based on their data. This analysis technique will allow engineers to quantify a location’s relative vulnerability of conditions favorable to sinkhole collapse when raveling conditions are encountered using an investigation test called the Cone Penetration Test (CPT). CPTs are a common subsurface investigation tool used by geotechnical engineers to identify soil layers and measure the strength of the soil within a project location. Through quantifying the raveling phenomenon, local engineers can better discern which mitigation techniques, such as compaction grouting or road closure, should be performed to lower the associated risk of sinkhole collapse.
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 [...]
Source: Construction Vibrations -NEW (7004IW2022) INSTRUCTOR: Antonios Vytiniotis, Ph.D., P.E 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 The workshop will cover a variety of issues regarding construction vibrations. It will start by describing the sources of construction vibrations, the propagation of vibrations with a soil and scatter effects. Then it will cover the effects of such vibrations in: 1) structures; 2) human perception; and 3) indirect effects of such vibrations. The workshop will cover examples of construction vibration effects in various structures and will show how conditions in structures can be evaluated to understand whether they are caused by vibrations. The workshop will show how construction vibrations can be monitored effectively by state-of-the-art equipment. Finally, this workshop will show how to analyze the data from monitoring to generate valuable insights about their effects on structures. A greater understanding of construction vibrations will help in mitigation of their damaging effects. Benefits and Learning Outcomes Upon completion of this course, you will be able to: Explain sources of construction vibrations Explain effects of construction vibrations Explain causation of damage potentially associated with construction vibrations Monitor construction vibrations Mitigate construction vibrations Avoid costly adjacent construction litigation Assessment of Learning Outcomes Achievement of the learning outcomes by attendees will be assessed through online discussion and case studies. A short post-assessment (true-false, multiple choice and fill in the blank questions) will also be administered. Who Should Attend Geotechnical Engineers Structural Engineers Civil Design Engineers Owners Construction City Planners Workshop Outline Day 1 Construction Vibration Sources Vibration Propagation and Energy Dissipation Discussion about Literature Data Interactive discussion and quiz about sources, propagation and state of the practice Human Perception of Vibrations Direct Effects of Vibrations Interactive discussion about effects [...]
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 [...]
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 [...]
Source: A Climate Change-Induced Disaster in Denali National Park | Time The Times has recently showcased an article on the current rockslide situation in Denali National Park. The effects of climate change have been dramatic with the current melting of the permafrost. The National Parks Service has recently upped through gravel removal of the Pretty Rocks Landslide in an effort to keep up as the rapidly thawing permafrost picks up pace. Alaska is right now recognized as the country’s fastest-warming state. The landslide hit unprecedented speed 4 weeks ago causing the team to close the back half of the park weeks earlier than anticipated. This only signals bad news as reservations are canceled in the short term and the long term implications are yet unknown. “This is the canary in the coal mine for infrastructure disruption in Alaska,” says the Camp Denali lodge owner Simon Hamm. “If things continue on the path they’re on, it’s not going to just be Pretty Rock—it’s going to be half of the Alaskan highway system.” Rapid deterioration Denali National Park is one of the U.S.’s largest national parks at 6 million acres, and sits about four hours north of Anchorage. While the entrance to the park is certainly beautiful, many people prefer to hop on buses to access the park’s marquee attractions deep down its single 92-mile road: views of Mt. Denali (formerly Mt. McKinley), the highest peak in North America at 20,000 feet; the gleaming Wonder Lake; rolling mountainsides that contain an abundance of wildlife, including grizzly bears, moose, caribou and bighorn sheep. About halfway along the road lies the Pretty Rocks Landslide, a slowly sliding section of earth that acts more like a glacier than a rockfall. Since the 1960s, permafrost deep below the earth’s surface has thawed, causing the soil and [...]
Geotechnical Instrumentation and Monitoring Consumption Market Size to Witness Huge Growth by 2027 | By Top Leading Vendors – Keller, Fugro, Nova Metrix, Geokon, Geocomp, Sisgeo, Cowi – The Daily Chronicle
Source: Geotechnical Instrumentation and Monitoring Consumption Market Size to Witness Huge Growth by 2027 | By Top Leading Vendors – Keller, Fugro, Nova Metrix, Geokon, Geocomp, Sisgeo, Cowi – The Daily Chronicle
A Cone Penetration Test (CPT) also referred to more informally as a Cone Test, is a way to get at subsurface information without having to directly sample the subsurface. Many organizations that order drilling services are also using CPT within their operations. CPT testing services is a good support option to well drilling services, since many of the potential customers and skills overlap. What is Cone Penetration Testing? Cone Penetration Testing (CPT) is the practice of using an ASTM standard hardened cone shape that is directly pushed into the ground to substantial depths. The cone is pushed using steel rods that are able to be connected to each other in 1 meter lengths as the depth increases. A powerful hydraulic ram is used to generate a substantial amount of downward force to enable the cone to penetrate soils, sand, clay and sometimes even soft rock. In order to keep the surface equipment (truck) in place and not simply be lifted up by the ram force, the vehicles that the CPT equipment is mounted on or in are typically quite heavy. Also, the use of anchor systems to the ground will increase the ability of any vehicle mounted CPT system to push harder and therefore deeper. There are a couple of different imperative goals to any subsurface investigation. The first one is the nature and sequence of strata or soil,sediments and other geological subsurface features. Using CPT for this is called geo-technical testing. In addition, the groundwater conditions can be established during a sounding. CPT can be used to determine: the composition, strength and distribution of subsurface soils. These can range from clay, sand, bedrock, groundwater table, hydrocarbons, contaminants and more. Advantages of CPT There are many different advantages to Cone Penetration Testing (CPT), including, prompt collection and interpretation of field [...]
Geo-Congress 2014, Atlanta, Booth 105 Join us at Geo-Congress 2014 in Atlanta starting Sunday, February 23rd and running through Tuesday, February 25th, 2014. We're excited to be a part of this historic gathering, the first Geo-Institute conference focused on sustainability. CPT is an important part of structural design, including sustainably focused projects. It is also a vital technology for ground water monitoring, protection and soil remediation which are essential to sustainable development. Vertek CPT is excited to be sharing the latest breakthrough CPT tools including the new S4 quick attach CPT system! We'll be planning our spring product demo schedule that is kicking off in May. So stop by booth #105 to arrange a time and place to experience these products first hand and see how Vertek CPT can help you to be successful in the CPT business. Hope to see you there!
In terms of measuring soil contamination, measuring soil electrical conductivity can provide useful information for a more complete site characterization study. Measuring sub-surface soil electrical conductivity is becoming less expensive as well as faster and easier. This form of measurement has most commonly been used for measuring physical and chemical soil properties but the ability to pinpoint contaminants is improving, particularly with software designed for the job. How to Measure Soil Conductivity Measuring soil electrical conductivity is facilitated by two different types of sensors, a contact sensor and a non-contact sensor. Contact sensors work by making contact with soil to measure electrical conductivity directly. These types of instruments are most often used along the surface of a field to characterize the soil for agricultural purposes. Non-Contact Sensors Non-contact sensors, as the name implies, function without having to touch the soil directly. This method is based on the measurement of the change in mutual impedance between a pair of coils passed through the soil. Electricity is applied through the coils, which creates a magnetic field. Much like the way an induction motor operates, this magnetic field induces an electrical current in nearby materials that are magnetic. You can assess the level of current induced by measuring the impedance in the operating coils. Passing non-contact sensors down a borehole has been used effectively to establish geophysical properties such as the presence of clay (which may have highly conductive materials distributed through it) and water table levels. In cases where an area is known to have contamination, the identification of clay layers and groundwater distribution can help to estimate where 'plumes' of contamination might be contained orspread underground. In the case of a borehole test, water samples can be gathered directly from discrete depths to confirm the presence of various types of contaminants. [...]