Prestressed Concrete Introduction Pre-stressed concrete is a form of concrete where initial compression is given in the concrete before applying the external load so that stress from external loads are counteracted in the desired way during the service period. This initial compression is introduced by high strength steel wire or alloys (called ‘tendon’) located in the concrete section. Why is Pre-stressed Concrete Required? Before get started let’s go back to some basics first. We know, concrete is good at compression but very weak in tension. And so we see after external loading, in the bottom part of concrete, a tension zone occurred. So, it tries to be elongated and guess what? It cracks. This is why we add some at the steel bars bottom section so that it can resist most of the tension and save concrete from cracking. This is our traditional RC structure. But what about some megastructures with larger beam span? Think about a flyover or famo...