Atterberg Limits Testing is just one of the testing methods that Encorus’s Civil Testing Group uses to determine properties of soil. According to ASTM International, Atterberg Testing Limits are six limits of consistency in soils that were defined by Albert Atterberg. These limits include the upper limit of viscous flow, the liquid limit, the sticky limit, the cohesion limit, the plastic limit, and the shrinkage limit. In modern engineering, the term Atterberg Limits commonly refers to only the liquid limit, the plastic limit, and in some cases, the shrinkage limit.
The liquid limit of soil is the minimum amount of water that would be added to a set amount of soil to change its consistency to a liquid state, meaning that the soil cannot retain its shape. The liquid limit of soils can be determined by creating a paste using soil and a small amount of water and putting it in a liquid limit device. The paste is separated into two halves using a grooving tool, and then allowed to flow together from the shocks caused by repeatedly dropping the device’s cup in a standard manner. This process is repeated with different amounts of water in the paste and the results are plotted on a graph to establish the liquid limit.
The plastic limit of soil is similar to the liquid limit, but it is the amount of moisture that causes soil to display plastic characteristics rather than liquid or solid ones. The plastic limit can be determined using a rolling method where the soil sample with a recorded amount of water is rolled into a 3.2 mm thread and broken into smaller and smaller pieces until it cannot be re-rolled and broken down any more. This process is done twice, and then the average water content of both trials is calculated to determine that soil’s plastic limit. The plasticity index of a particular type of soil can be found by determining the difference between the plastic limit and the liquid limit.
The shrinkage limit of soil is the maximum amount of water in soil that makes it saturated, but still in a solid state. When you add water to soil, the volume increases. However, when a soil sample reaches its shrinkage limit, the volume of the soil does not decrease when the amount of water is decreased even further. The shrinkage limit can be found in a soil sample by determining the relationship between initial wet mass, initial volume, the dry mass, and the volume after drying.
According to the ASTM International Designation: D4318–17E1 , “The liquid limit, plastic limit, and plasticity index of soils are also used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, hydraulic conductivity (permeability), compactibility, shrink-swell, and shear strength”. These testing methods are crucial when it comes to determining what type of soil to use as a foundation for construction projects. The properties mentioned above will affect the soil’s ability to maintain its durability under different forms of agitation. Therefore, it is essential for construction professionals to test the soil before starting construction to ensure the long-term integrity of the structure being built.
If you require Atterberg Limits Testing, contact Civil Laboratory Supervisor Jeremy Lake at (716) 592-3980 ext 133, or email@example.com.
Please join us in congratulating Andrew J. Wiedemann for passing the Principles and Practice of Engineering (PE) exam in fire protection!
Andy, a graduate of Alfred State College, recently celebrated his tenth year with Encorus. His successful completion of the exam demonstrates his knowledge and judgement in the application of science and engineering to protect the health, safety, and welfare of the public from the impacts of fire. As a Fire Protection Engineer, Andy’s responsibilities will include tasks such as the evaluation of hazards and protection schemes, design of fire detection, alarm, and suppression systems, and the review of work prepared by others.
The 8 hour PE Fire Protection Exam is administered only once each year by the National Council of Examiners for Engineering and Surveying (NCEES), the national non-profit organization dedicated to advancing professional licensure for engineers and surveyors.
One of the lesser known services that Encorus Group offers is control systems engineering design. This discipline is relatively broad, so Senior Electrical Engineer Tom Gilmartin elaborates on when control systems engineering is widely used, which is in the manufacturing process.
A manufacturing process can be thought of as a lineup of equipment in a factory used to produce a product. The product can be anything, from orange juice to airplanes. The process usually includes equipment such as pumps, motors, fans, robots, conveyors, and the like. Typically, a process engineer designs how the system is to function, determining how much of which item (water, chemicals, parts, powder, etc.) has to move where in the system.
Once the process engineer has defined the process, mechanical and electrical engineers step in and design a system to perform the process. This might include sizing equipment, designing electrical feeds, laying out the process physically and fitting it into a building.
With the process defined, and the power and mechanical equipment selected, the controls engineer is called in to finalize the process. The controls engineer, with some help from others, selects instruments necessary to make measurements on the process, such as flow, pressure, temperature, etc. The controls engineer designs communications and wiring to allow all the instruments and devices to communicate to an industrial computer. The computer is programmed to run the process, and to monitor its operation. This often includes a “human machine interface” (HMI), typically a computer screen and keyboard, which provides a visual representation of what is happening in the process as it runs. Controls engineers will start up and test the process, adjusting programming as needed to produce the product correctly.
After the process is functional, it is turned over to plant personnel and run by plant operators. Normally the system will operate for 10 years or more, cranking out its intended product. Once the system begins to fail, the procedure of creating a new manufacturing process begins again.
If your company has a requirement for control systems engineering design, contact Director of Engineering Design Services Tom Gilmartin, PE, PMP, LEED AP, at (716) 592-3980 ext. 124, or at firstname.lastname@example.org.
We recently celebrated the holidays with our Encorus family! Head over to our Facebook page to vote for your favorite party photo! Happy holidays from the Encorus family to yours!
Many people are familiar with the common types of engineering: civil, electrical, mechanical, environmental, structural, and so on. But one discipline that might not be so widely known is forensic engineering, also referred to as investigative engineering.
Forensic engineering can be anything that requires an investigation into the origin and cause of a structure or object’s malfunction. These investigations and subsequent engineering reports are conducted by licensed professional engineers. This type of engineering is more common than most people may think. Insurance companies often call upon professional engineers to investigate claims that people make for some type of damage to their house or building structure. Professional engineers are brought in to analyze the situation and determine if the insurance claim is legitimate, who should pay for the damage, and the possibility and scope of repair. Property owners, plant managers, and others may also request forensic engineering services
Weather-related events such as wind, ice, hail, and snow are frequently the cause of structural damage. Foundation shifting, roof damage, burst pipes, electrical malfunctions, and other structural and equipment issues can be subject to a forensic engineering investigation in order to determine the cause of damage. Fire origin investigations are also common in forensic engineering, in addition to the evaluation of the structural integrity of the building or area involved in the fire. Equipment failures or malfunctions can also be investigated.
Encorus Group has several licensed professional engineers on staff who have experience performing forensic investigations. If you are in need of forensic engineering services, call Tara Lowry at 716.592.3980, ext. 120 or email email@example.com.