What is Structural Engineer?

As per tests, shear strength of a concrete does not increase in direct proportion with member depth. As per ACI, this phenomenon is called the Size Effect. Do mind that it is the contribution of Concrete only, and not including its reinforcement.  What this means is, a concrete block with X depth does not have twice the shear resistance of block with depth X/2.  As per ACI 318-19, How this acts in terms of one way and two shear can be seen from the code books. It's more dominant  in two way shear, a heads up. You can see from a simple calculation that the size effect factor of a 1000mm thick reduces the shear resistance of an element to around 63% of the original strength. But wait, if that's the case, won't the requirement for footings which take all the loads from the structure be too much. Clause 13.2.6.2 to the rescue. It permits the negligence of size effect factor for foundations. What a miracle. No it isn't. It's all calculated that's what I believe.  Now...

Structures are built to last. Most modern structures have a life expectancy much more than a regular person. So it's only natural to assume Engineers designed for it. We do design checks in this regard too.  It was not always a thing though, at least that's what I believe. And I will tell you why I think so. Civil Engineering is the oldest branch and has gone through some vey serious updates. My trade initially started with the Working Stress Method. It is also called the traditional method. In this, the design is based only within the elastic limit. Which means, the materials used for construction behaves in a linear elastic manner. You know how an elastic rubber works, it won't break unless stretched through its capacity. The philosophy is similar. As long as it is within the limit, it won't fail. But to make the structure not reach its limit, the materials required was much more. This, at times, leads in very un-conservative designs. This Method is good for critical ...