Structural Stress Analysis

During the industrial boom from the 1920s to the 1960s, we saw a surge of new infrastructure throughout the United States. Now that many of these buildings and bridges are getting old, there are some severe signs of wear and tear that must be addressed. According to the article “Fatigue Analysis of Concrete Structures” by Structural Engineer Dilip Khatri, PhD in Structure Magazine, analyzing the fatigue of these structures is important for these three fundamental reasons:

1. It leads to fractures, cracking, and eventual collapse/failure because the structure will likely fail before it reaches its yield point. This poses a life-safety threat to occupants.
2. Designing for strength, ductility, dynamic response, strain compatibility, and serviceability are fundamental but have no correlation to fatigue analysis. A structure can be code compliant and still fail in fatigue. Increasing the strength does not necessarily contribute to better fatigue strength.
3. Fatigue failure is the result of cyclical stress over an extended period that eventually fractures the material and causes failure. These fractures will grow and ultimately undermine the strength of the system.

Khatri’s article stresses that it’s important to raise awareness about analyzing structural stress for the “long-term performance of concrete and steel structures.” Concrete structures that are heavily impacted by fatigue loss due to regular stress include bridges, hospitals, pavements, theaters, stadiums, and office buildings. These are critical areas to ensure the safety of the structure because thousands of people frequent them consistently.

When many of these structures were being built, there was zero attention given to fatigue loss potential during design, according to Khatri. It was not typical practice or taught in coursework. He states: “As the profession continues to evolve into more esoteric, analytical, and focused areas, structural engineers realize that the issue of fatigue is more than just a textbook discussion and has very real implications on the long term considerations of structures.” His advice is for the US to incorporate fatigue loss mitigation into education, practices, and designs. As more buildings age in our country, fatigue analysis will become more and more important. Inspection and repairs are major considerations when designing or updating our country’s concrete and steel infrastructure.

Some older structures may need a full replacement to be safe an effective. Sometimes damage is not visible and needs non-destructive testing to be performed by an engineer to get a deep look into the structure of a building. There are seven main reasons why concrete fails: natural wear and tear, no maintenance is performed, lack of expert craftsmanship, inadequate materials, atmospheric factors, physical factors, or following the wrong specifications. Concrete may be durable, but it requires professional application and some level of care through the years. Damaged concrete needs accurate measure to ensure proper repair or replacement.

For your concrete needs at home or at your office, Lift Right Concrete is your go-to, professional source. We understand the factors that go into quality concrete, including the weather impacts from our unique climate here in Utah. If you’re concerned about your concrete, give us a call today.