Design of Concrete structures: Report Assignment Due Date: You are expected to research and write a report at least of five A4 pages in the topic of Prestress concrete. You should at least cover the...

Theory:
Prestressed concrete was mainly developed by Freyssinet in France, Hoyer in Germany and Magnel in Belgium. It was during the later part of 19th century when the idea evolved but it took to 1920s for its materials development to come to a level where it can be used with confidence. In Pre-stressed concrete before giving any external load, an initial compression is given so that later the external load stress can be counteracted in a desired way. This initial stress is formed by high strength steel wire or alloys called tendons.
This idea has then been used in many other forms, like:
· Riveting
· Wagon wheels
Where heated metal is fitted in an object. And in the process when the metal cools it contracts inducing prestress in the object.
So, if you take a basic everyday example then we can consider a row of books can be picked up by putting pressure at the two ends together. These row of books have zero tensile strength. So, once we provide external stress( the prestress), that compress the books together, they only get separated if the self induced tensile stress is greater than the given compressive prestress.
Few Advantages of Prestressed Concrete:
· Durability
· Smaller section sizes
· Smaller deflections
· Increased spans
But as a disadvantage the construction cost is more than RCC structures.
Places where we use Prestressed Concrete:
· PSC Pipes which are Pre-tensioned precast
· Communication pole
· Barges
· Railway sleepers
· Using post-tensioning, Precast segments are joined.
· Bridges
· Water tanks etc.
Basic Design of Pre-stressed concrete:
Types of Pre-stressing:
There are mainly two types of prestressing:
· Pre-tensioning, which means prestress to steel strands before casting concrete.
· Post-tensioning, which means prestress to steel tendons after casting concrete.
· Pre-tensioning
It is mainly used for...