Articles Master of Civil Engineering

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4 Insights on Factor of Safety in Engineering

Hard Hat and Gloves

 
The civil engineering discipline utilizes a number of protocols and procedures to help guarantee that completed civil engineering projects are stable and safe for use. Such protocols not only help identify weak areas within the infrastructure, but also assist in determining how strong infrastructures need to be, especially in order to withstand natural disasters. One of the methods utilized in this process is factor of safety, which aids civil engineers with accurately determining and applying the appropriate building material.

How Factor of Safety is Determined

To determine the factor of safety, civil engineers must divide the maximum allowable stress (the amount of stress that the part or infrastructure was designed to handle) by the working stress (the amount of stress that is required or applied). For example, if a metal beam has the stress capacity of 800 kilonewton (kN), and the amount of stress being applied to the metal beam is 400kN, then the factor of safety is 2 (800kN/400kN); the metal beam would be able to support twice the working stress before failing. If the metal beam had the stress capacity of 400 kilonewton, then the factor of safety would be 1 (400kN/400kN), and the metal beam would only be able to hold the working stress.

Importance of Determining Factor of Safety

Civil engineers also rely on factor of safety to understand how long an infrastructure can be used, how much stress can be applied through everyday duties, as well as the maximum amount of stress that could be applied during natural disasters. Due to the involved safety concerns, factor of safety is often referred to in financial discussions, particularly those investing in or insuring an infrastructure. Without knowledge of how much stress an infrastructure can hold, institutions could be at risk of litigation due to improper use or structural failure. To help protect against failure, structures are often designed to have a maximum stress which exceeds the amount of required stress for even emergency situations.

Infrastructure vs. Material Factor of Safety

Civil engineers should understand that the factor of safety of materials is different from the factor of safety of an infrastructure, because specific materials or sections of a structure may at times experience stress that doesn’t impact the entire infrastructure. This additional stress may include imbalanced weight distribution, rust, weather destruction, faulty materials or improper construction. Due to the variety of stress, materials may have a different factor of safety than the infrastructure. For example, an entire bridge may have a factor of safety of 3, yet an adjacent wooden observation deck may only have a factor of safety of 2, meaning that the observation deck would only be able to support twice the working stress before failure, whereas the entire bridge could support three times as much.

Trends Regarding Factor of Safety

Technology has had a major impact on the civil engineering industry and many technological innovations have assisted civil engineers in determining the factor of safety. Digital software and platforms have provided civil engineers with an increased accuracy for determining an infrastructure’s maximum stress capacity. Within these platforms, civil engineers can test a number of hypothetical situations to develop a more accurate – and much safer – idea of how much stress materials and infrastructures can hold.

Another major advancement that is influencing factor of safety is nanotechnology. This burgeoning industry is assisting in the creation of safer, higher quality materials, such as fibre sheets that contain nano-silica. With nanotechnology, civil engineers are able to mix and leverage nano-sized particles which expand the materials available for construction projects.

As the civil engineering industry continues to advance with the help of progressive technologies, civil engineers will need to remain familiar with the factor of safety and other protocols which help ensure that infrastructures are safe for users and the surrounding environment. By continuing to maintain safe, effective infrastructures, civil engineers can continue designing innovative and efficient structures which will enhance the human experience for years to come.

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As the nation’s oldest private military college, Norwich University has been a leader in innovative education since 1819. Through its online programs, Norwich delivers relevant and applicable curricula that allow its students to make a positive impact on their places of work and their communities.
Norwich University offers exceptional opportunities to help advance your knowledge, target your skills, and gain greater proficiency as a professional civil engineer. The online Master of Civil Engineering program at Norwich University is designed to enhance your technical knowledge, management skills and engineering competence by delivering a modern, practice-orientated education that fosters creativity and critical thinking for problem solving and innovation.

Sources:

http://www.engineeringtoolbox.com/factors-safety-fos-d_1624.html

http://theconstructor.org/geotechnical/factor-of-safety-for-different-foundations/5537/

https://www.engineersedge.com/analysis/factor-of-safety-review.htm

http://www.sciencedirect.com/science/article/pii/S1878535214002962

February 2017