Thursday, October 21, 2010

A year for a flyover

An average flyover in India takes a year to make - give or take a few months. I am pretty sure that the time required to build a flyover can be crunched to a few months.

Now, I am no construction expert, but commonsense suggests that in any activity there are parallel activities and sequential activities. In the case of the flyovers, it appears that much of the work is being done in a sequential manner. Take for example, the pile drilling rig. The
flyover builders have exactly one per flyover. Commonsense suggests that having 2 or 4 of these machines will help them drill piles 2-4 times faster. Then post that the pillars are constructed; again, there is no reason the pillars have to be constructed one after the other - they can all be done simultaneously - or atleast 50% of them - so that time required for the concrete to harden/settle is better utilized. And then the actual bridge which rests on these pillars - can be constructed - since they consist of pre-cast elements that are mounted on the pillars. Easily all this can reduce construction time by half at the very least.

What I have written is purely from observation. No doubt flyover construction in India has progressed in the last decade or so - from the kerosene powered pile diggers to pile digging rigs, but the way the companies handle flyover construction shows a problem of a lack of
scale. The companies can bid for more flyovers if they have the scale, but they don't want to build scale and wait for projects. So, because of this chicken and egg situation they understaff their projects and it results in everybody bidding for about a year for each flyover. Infact nearly 10 years ago, Mumbai (with the traffic constraints) showed that flyovers can get done faster with the right incentives - and the Delhi and Bangalore metro (essentially a flyover with larger capacity) also shows that this type of construction can be done much faster.

So, why do our flyovers take ages to construct?

1 comment:

ankur said...

apparently, flyovers can be constructed over a weekend!

A few years ago, a company presented this concept to DDA in Delhi. Seems like this happens in Taiwan already.

The idea is that the entire flyover will be pre-fabricated offsite. Over a weekend, it will then be 'deployed' on site. Of course, actual time taken will be a bit longer, because there will be issues like moving utility stuff like water pipes, cables etc, but still doable in a month.

Would have cost something like 10% to 20% higher. Nothing came of it, though.