#phd engineers

This did not happen to me, but I was told this over beer by the person who it did happen to.

Prestressed Concrete is an important technology. You cannot drive over most bridges, or Park your car in the city without encountering it. I worked for over 10 years in the industry and became quite an expert. It is a bit strange, interesting and not a little dangerous. The basic idea is you stretch very small strong wire cables inside concrete shapes to apply compression force to it. Concrete is very strong in compression and rather weak in tension. Apply enough compression and it does not see much if any tension. That is good as without tension it does not crack. Well made concrete will last millennia. No lie there many Roman buildings are made with concrete. Look up the Roman Pantheon. They invented it.

When you work with this method you learn a few basics. For example you pull the stressing strands to almost 90% of breaking strength at some points. The strands are strong, far more than carbon fiber for example. How is 270,000 psi for you. CF is good for 100,000. Hah.

The story begins:

A prestressed concrete fabricator got a contract to build a series of large underground rapid train stations in a downtown area. They were to supply big girders to span the stations and the tracks under the city streets. A very important job. Not a little intimidating. So they hired a PhD engineer to do the design work who claimed to be an expert.

Thing is many PhDs are divas and the most extreme are narcissists of the "I know everything" type. It is an insult to criticize or question their opinion or capabilities especially if you only have a Bachelor's degree. A section of that is they may not ask for help as that is weakness. So this guy went into his office and started to work. Weeks later the management got nervous. It was taking a long time and nothing was coming out to complete the drawings that need to be submitted. Nervousness gave way to worry and serious concern.

They sent a young engineer in to ask him how it was going. The mission was to look over his shoulder to see what was wrong. The PhD said he almost had it figured and would soon be ready with the calculations. The young guy said; "I have been told by management to help you so we can get this done." This guy was the person with which I was having the beer. The Doctor of Engineering reluctantly showed him his basic work.

Prestressing steel is special. It is stupid strong and when it is made it is stretched past its elastic limit to just shy of breaking. This is called strain hardening. Normal reinforcing steel is pretty strong, but it is only a fraction of that of prestressing steel. 18% as strong in most cases.

At the time the standard cables were 7 wire strands of a gross 1/2" diameter with an area of 0.153 sq inch. There were also 1/2" reinforcing bars with an area of about 0.2 sq inch.

The punch line is this person was no expert and had never worked with prestress before. His ego assumed he could figure it out so when asked he said of course he was an expert. He had no idea what a prestressing strand was. He had been trying to prestress big girders with normal reinforcing bars and found it very hard. Hard because it was impossible. He was fired.

We had a good laugh over this, but it was a serious problem. I never heard what happened to this guy. I expect due to the sensitive nature he was let go quietly and the engineering association may not have been told. Today that kind of thing is met with suspension and prohibition from work. He probably went to teach university in a far off country.

Every profession has its Divas. Senior engineers object to comment or criticism from underlings. Even just questioning if they checked this or that may trigger them. It is made worse by how up the academic ladder they climbed.