During the design phase of a structure, there are certain loading conditions that engineers need to take into consideration. One of those loading conditions is seismic load, which is a dynamic load caused by the acceleration of the earth supporting the structure. Earthquakes can occur in any location at any time with increased activity near known fault lines. In fact, the Western New York area is located near a fault line, The Clarendon-Linden fault. This fault line is not expected to produce a major earthquake event; therefore, the area is generally considered a low seismic area.
Engineers use performance-based design to determine the seismic forces that would be applied externally to a structure and compare that load to other dynamic loads, such as wind forces. Performance based design requires structures to perform based on its purpose, occupants, location, and soil characteristics underneath. Engineers will look at ground motion response acceleration maps as part of the seismic load calculation. Seismic design is required for most designs, and there are very few exceptions in the International Building Code. Sometimes these exceptions in the code are overridden by state and local code requirements.
Building materials with high ductility such as steel and wood are often used to resist seismic forces. Ductile materials allow a structure to flex, absorbing and dissipating energy when subjected to sudden earthquake forces. Brick and concrete structures can be designed to resists seismic forces. However, ductility needs to be built into those structural systems. This is typically done with steel reinforcement.
Certain areas of the world require more consideration for seismic design. Higher seismic areas, such as the West Coast of the United States, require structural systems and connections to be seismically qualified. It is very important for an engineer to select a structural system that makes efficient and economic use of the materials chosen to keep the risks at a minimum.
If you or your company has any need for or questions about seismic design, contact Senior Structural Engineer Daniel Sarata at firstname.lastname@example.org or (716) 592-3980 ext 138.
Encorus’s Structural Engineering department provides more than just structural designs. One of our many capabilities is shipping container evaluations. Our shipping container evaluations have been requested by both manufacturers and the end users. The typical contents of the shipping containers Encorus evaluated have been nuclear waste. This requires a robust ASME NQA-1 program to ensure safety. The containers can be fabricated from steel components and can be lined with reinforced concrete, lead, or other material. Container loads are not limited to just the weight of the container and its contents. Evaluations must take stacking loads and various impact loads into account. Minimum impact loads are dictated by the Department of Transportation (DOT) and involve impacts from projectiles while stationary, and container drops from a certain height. The intent of applying these extreme loads is to ensure the structural integrity of the container, therefore maximizing safety to the public.
Encorus has experience in evaluating industrial package (IP-1), 7A Type A, specialty, and shielded containers. Industrial Packages (IP) are sub-divided into three categories designated as IP-1, IP-2 and IP-3, which differ regarding the degree to which they are required to withstand routine and normal conditions of transport. The required tests simulate normal transport conditions such as a fall from a vehicle, exposure to rain, being struck by a sharp object, or having other cargo stacked on top. Packages used in industry such as steel drums or bins could meet these various requirements, but purpose-designed packages are also frequently used. The choice depends on the characteristics of the material. Some typical materials transported in industrial packages are low-level and intermediate-level radioactive waste, or ores containing naturally occurring radionuclides (e.g. uranium or thorium) and concentrates of such ores.
Type A packages are used for the transport of relatively small, but significant, quantities of radioactive material. Since it is assumed that this type of package theoretically could be damaged in a severe accident and that a portion of their contents may be released, the amount of radionuclides they can contain is limited by NRC regulations. In the event of a release, these limits ensure that the risks from external radiation or contamination are very low.
Type A packages are required to maintain their integrity during normal transport conditions and therefore are subjected to tests simulating these conditions. Type A packages are used to transport radioisotopes for medical diagnosis or teletherapy, technetium, generators used to assist in the diagnosis of certain cancers, and also for some nuclear fuel cycle materials.
If you require shipping container evaluations, please reach out to our Senior Structural Engineer, Dan Sarata, at (716) 592-3980 ext 138, or at email@example.com.
Photo credit: SECUR LLC
Dynamic Cone Penetrometer (DCP) testing is a method of measuring the strength of loose soil that has not been disturbed, or compacted materials under existing field conditions. This is an important test to perform if any type of construction is planned for the area.
According to ASTM, the test method is used to “assess the compaction effort of compacted materials” based on the force and number of repetitions that it takes for a hammer to penetrate the material. This is called the penetration rate, which helps to determine other construction characteristics of the material, such as strata thickness and shear strength.
The test uses a hammer-like instrument that is comprised of a vertical rod that is driven into the soil, which then causes a measurable extension of the rod. The measurement is then taken into consideration along with other characteristics, such as density and strength, to determine if any precautions or limitations should be implemented in the construction process.
Encorus will be providing DCP testing services for the Buffalo Amtrak station renovation and reconstruction project. Senior Geologist Andy Kucserik and Technician Adam Svensson will be performing the testing in areas that are bound by the existing Amtrak railroad lines and an underground sewer tunnel.
If you have any questions or require DCP testing services, please contact Senior Geologist Andy Kucserik at (716) 592-3980 ext. 149 or firstname.lastname@example.org.
Citation: ASTM D7380-15, Standard Test Method for Soil Compaction Determination at Shallow Depths Using 5-lb (2.3 kg) Dynamic Cone Penetrometer, ASTM International, West Conshohocken, PA, 2015, www.astm.org
One of the several environmental services that Encorus offers is a NEPA review. NEPA is a very important component in the environmental engineering field, but many non-environmental engineers may not know what NEPA is in the first place, let alone if they need a NEPA review. This article will explain what NEPA is and why it is important in environmental engineering.
The National Environmental Policy Act (NEPA) was signed into law on January 1, 1970. Using the NEPA process, agencies evaluate the environmental and related social and economic effects of their proposed actions. Agencies also provide opportunities for public review and comment on those evaluations. Before NEPA was established, federal agencies were missions focused, to get goals accomplished as quickly as possible, with no required regard for environmental impacts.
NEPA requires that federal agencies evaluate environmental impacts of projects by preparing Environmental Assessments and Environmental Impact Statements (EIS). These documents establish positive and negative impacts of a project on the environment. This information is used by agencies in establishing a number of alternatives to successfully reach the project goals. These alternatives can lead to the project being abandoned, if no suitable alternatives are acceptable to the agencies involved.
The public is included in this process by commenting on proposed projects. These can be submitted comments, or can be by public hearing. This gives people the ability to voice concerns or support for projects that would impact their lives, jobs, and environment. The NEPA process can be confusing and time consuming and it is recommended that you work closely with the consultants and government agencies involved.
If you are interested in learning more about the National Environmental Policy Act, or are curious if your project requires a NEPA review, please contact Encorus’s Environmental Engineer, Mary Padasak, at (716) 592-3980 ext. 144, or email@example.com.