Have you ever considered what goes into the building of things such as bridges that are supposed to support many tons of weight of vehicle traffic every day for decades? Every detail from the steel in the wire cables to the construction of the rivets or bolts needs to be considered. In designing things for modern use I use software such as Ram Connection. This helps with determining what type of steel fasteners to use in the construction process. There is a lot of detail that goes into the biggest and tiniest components of every bridge you have ever went across, and you should be thankful that top quality computer programs are there for designers to be able to use.
Did you know that the markings on bolts mean something? They might just look like a line or dot or something to the untrained eye, but they tell about the steel and its hardness for the bolt in question. There are specific bolts and nuts to be used for different applications when you are building a bridge. If you use the wrong stuff, you can cause a catastrophic failure that can lead to serious issues. Bolts that are too hard will snap and break under stress. Bolts that are too soft will stretch and loosen and break. Steel fasteners used in commercial and industrial construction are a big deal, and there is software to figure out which ones to use.
My family has a long line of engineers and architects who built things. I am very happy to have software such as Ram Connection. My grandfather has told me how he used to share computer time to run calculations he programmed onto punch cards back in the 1970s. I cannot even imagine needing to do that. Having access to design software to build these massive structures and make sure they fasten together properly is much appreciated by me.