Conservatism but not over-designing

“Why do you consider the safety factor of 1.5 instead of 1.3, or why deliberately increase the pole size to CHS114.3 if CHS88.9 would work? – It is for conservatism.”

Sometimes we like to use of the word “conservative” to imply that we’re assigning values that we know to be too large (or too small, depending on the situation), when in reality we simply don’t have an accurate handle on the “real” value. The implication is that we might produce wasteful structural designs by using additional material which leads to unnecessary cost increase for clients. More interestingly, there seems to be more perception about that engineers are more conservative than they used to be. Or that structures are bigger than they once previously might have been. We often encounter a case that the analysis performed on the existing telecom structure that has been in service for over 10 years show failed result. So what is changed? Is it the materials? The factors of safety?

As engineers we try not to make any assumptions, but in reality there are many unknown inputs during design process. In this case, conservatism might have to be involved in the analysis. However, conservatism sometimes can be mitigated by in depth consideration of the design variables. For example, applying the wind loads based on the actual wind direction instead of applying the worst wind load for all directions. During the completion of thousands of telecom projects, KAEG never stops refining and improving our design process and methodology to enable our structural analysis as closer to reality as possible by utilizing our in-house database and programing capability. We are always aiming to provide our clients with not only economical but fast turnaround design solutions.