DEC President and CEO Michel Maksoud, PhD, PE, has more than 30 years of experience in structural engineering. He recently provided this article to the Structural Engineers Association of Texas (SEAoT), the largest and most active association of registered structural engineers and allied professionals in Texas.
When it comes to reviewing structural engineering designs, it pays to go above and beyond. Here are three examples of problems discovered and lessons learned from which engineers of all levels of experience can benefit.
Example 1: Torsional reinforcement in a two-drilled shaft straddle foundation for a bridge column
A general engineering consultant (GEC) was asked to review a design already signed and sealed by a professional engineer. The consultant was not expected to check calculations but noticed that something looked off. Having design experience with a similar arrangement, the consultant noted that his previous design had double the torsional reinforcing offered in the drawing he was reviewing. At his suggestion, the designer reviewed the design and doubled the torsional reinforcement.
Lessons learned: Make sure you have current design knowledge and that the design checker has the proper experience and knowledge. Consult with more experienced engineers, especially for the design of structure types which you have little experience.
Example 2: Noncontact lap splices between a drilled shaft and a rectangular bridge column
Noncontact lap splice treatment was defined at the time when splicing reinforcement between a circular drilled shaft and a circular column. Rectangular columns were not addressed. The simplified effect of noncontact laps was increased tie size and reduced tie spacing in the column and in the drilled shaft. Without the benefit of documentation on how to handle splicing a drilled shaft to a rectangular column, the structural engineer researched the theory to understand the forces involved and developed equations and procedures to perform the splicing. The engineer wrote a white paper on the subject and shared it with the project team so that all designers could benefit from the research.
Lessons learned: In structural engineering, we need to understand why we do things. Knowledge of theory is very important, which is why I advocate for at least a master’s degree in structural engineering.
Example 3: Flood wall inadequate foundation
Above all, structural engineers have a responsibility to protect the public. An engineer received a flood wall design completed by another company when preparing to design the next segment of the wall. The engineer, whose company had no contractual relationship with the previous company, had concerns about the design. He expressed his concerns in a letter to the engineer, encouraging him to re-examine the design, which did not appear to be safe. The company revised its drawing, sent him a copy, and thanked him for catching the error. Fortunately, the matter was resolved without the need to escalate the issue.
Lessons learned: If you see something, say something. It is your duty as a professional engineer to protect the public. Remember to always make sure your design is properly checked by an experienced engineer.
In summary, it is not the lack of experience that leads to design failures. Instead, it is the lack of the right experience. The structures in the examples above were designed and sealed by professional engineers with an average of more than 20 years of experience. So why did we have design issues and how could we avoid them in the future? Below are a few more pieces of advice that may be helpful in your journey as a structural engineer.
Know the limits of your experience and act accordingly to mitigate them. This is very important when designing structure types in which you are not familiar.
Take the time to really understand the theory behind structural behavior. Cookbook design will work until it gets you in trouble.
Protecting the public is our highest duty. It may require uncomfortable situations such as contacting other engineers with whom you have no relationship, contractual or otherwise. Approach the situation with respect and work together for the good of the public. It is worth it.
Benefit from other structural engineers’ experience. I have always asked questions of others, even very simple ones.
If you are an experienced structural engineer, do some management by walking around (MBWA). Having casual conversations is a great way to share knowledge and problem-solve potential issues.
To my colleagues who prefer working from home, you will not be able to take advantage of MBWA both on the giving and receiving sides. I hope you can find a formula for taking advantage of it.
For senior engineers, when discussing a design with other engineers, junior or senior, give them the benefit of your experience. Explain how you performed a similar design and what was the theory behind it. I frequently share design issues with my staff that are related to the design being discussed.