Construction of Plunge Column by using Top Down Construction Method

Abstract

In an age where every square millimetre has the potential to earn money, it is essential to maximize the floor space
in today’s property developments and the extend goes to the record-breaking basements too. While this may seem
like another difficult demand for those involved in such projects, but our believe is that bar can be raised traditional,
buildings with underground basements are built by Bottom-up method where sub-structure and super- structure
floors are constructed in a sequence from the bottom of the sub structure to the top of the super-structure. Though
this traditional method is simple in both design and construction, it is not feasible for the huge projects with limited
construction time. So to counter this we have come up with top down construction as in the deepest underground
station in New Delhi, India at Hauzkhas. Top-down construction method as the name implies, is a construction
method, which builds the permanent structure members of the basement along with the excavation from the top to
the bottom. This construction method, which provides us with saving of the overall construction time, it is showing
increasing adoption for major projects where time factor is of primary importance. But this method wouldn’t be
possible without the help of the plunge columns that acts as a vertebra to this technique, which helps in holding all
the loads that is laid during the process. A plunge column is a structural steel or concrete section embedded in a
freshly poured concrete pile, eliminating the need for base plates and holding-down bolts. Plunge columns can be
installed into rotary bored piles to allow for a ‘top-down’ construction sequence; 'launching' the structures much
before the basement is excavated. By adopting this method of construction the client can gain advantage of a
reduced construction programme.