Structural engineers work in the field of analyzing structures. They are the hunter-gatherers of finding forces, stresses and deflections that all work towards building a strong structure. They also study the design of structures. They will know which materials work best and how they need to be positioned to ensure that a structure doesn't come tumbling down. This means analyzing the distribution of load in a structure. The functionality of a structure also needs to be considered so that it is not built in a place where it does not serve a function.
There are also design principles in structural engineering. Once again, choosing which materials a structure will be able to stand on is imperative. The engineer needs to think of the most efficient building materials that will ensure a sturdy structure. The structural engineer needs to focus on the safety of the project as well.This is something that wasn't done in South Africa in 2015. On October 14th, a temporary steel structure came crashing down onto a busy M1 freeway in Sandton, Johannesburg. It was said that a strong westerly wind caused a collapse. The collapse killed two people and injured 19.
Now, months later, the results of an investigation into the bridge collapse is being made available to the media. The company in charge of the build was an engineering and design construction company named Murray and Roberts. Professor Roelof Mostert, the head of the department of material science and metallurgical engineering at the University of Pretoria has issued his report of what happened to the structure based on his investigations.
"Essentially, the structure appeared to separate at the median supports. That is the center of the highway, where the lattice girders on the eastern side remained stationary for a while but the lattice girders on the western side moved towards the west and separated from those on the eastern side and landed on the road," said Gregory Harington, a structural engineer, speaking to Moneyweb about Prof Mostert's report.
The report further said that the swivel clamps used in the operation were not able to keep both sides of the scaffolding upright. The swivel clamps were supposed to connect scaffold tubes together. But, a collection of older clamps and newer clamps led to the structures collapse. The older clamps had a kind of thread that led to less clamping force. The force of the wind was too much for the clamps to handle, and due to the lack of tightening on-site, the temporary structure collapsed. The professor is saying "poor workmanship" led to the collapse, along with the strength of the wind.
Video Source: Moneyweb