Question
For column reinforcements, why is helical reinforcement sometimes designed instead of regular links with reasons?

Answer
The utilization of links for column designing in Britain is very well-liked. Except, in U.S.A. engineers have a propensity to use helical reinforcement in its place of regular links as helical reinforcement has probable benefit of protecting columns or piles against seismic loads. In addition, when columns reach failure state, concrete outside hoops breaks and falls off firstly, followed by eventual failure of entire columns. Peeling off of concrete outside helical reinforcement gives a warning signal earlier than sudden failure of columns as optional by G. P. Manning in 1924. In adding, it is capable of take up a higher working load than regular link reinforcement.

For example, helical reinforcement is adopted in designing of marine piles in Government piers.