Flawed design an invitation to flooding

Saveri Rajai, well-known architect, says even if concrete roads have their merits, the BBMP and the contractor are not going about the project professionally.

“They are just laying the concrete roads directly above the existing roads, without any inspections on the existing sub-base. I have not seen this happen anywhere else,” he told DH, after accompanying reporters on a tour to some sites. Rajai, who specialised in energy-efficient architecture at Oxford Brookes University, UK, has worked on several big projects in Bengaluru, such as German Consulate in Bengaluru and HLC International in Chennai.

US has given up on them

I know concrete roads are popular in the US but only on highways, or expressways, as they call them. They don’t do it in urban centres anymore. Such roads were built in the ‘70s and ‘80s but they stopped because of safety concerns. When you have straight roads, it is all right, but when you have bends and turns, it gets extremely slippery when it rains. The concrete surface smoothens with usage. It gets smoother and smoother and this is extremely dangerous for motorists.

Digging is expensive

The maintenance is extremely expensive if you have to dig the concrete and resurface it to repair the utilities.

Risk of concrete cracking

The base should be of a certain build up. It should be well-compacted and have layers of grading below. If that’s not done then it will start cracking.

If the existing asphalt roads sink, the concrete roads will not sink but crack. I believe the wear and tear for vehicles is higher on concrete roads. Another problem is the glare. The concrete roads abroad are coloured but here the concrete is white, which means the glare is too harsh. This makes riding difficult.

Levels are mismatched

The concrete road is higher than the footpath. Had they dug up the existing road before laying the concrete road, the difference would not be there. The concrete is now at least six inches above the road. The existing properties especially houses planned with the old asphalt roads in mind, will have to raise their level as well, or live with rainwater flooding in.

Drains sure to clog up

Another problem is that the depth of the drain along the footpath reduces by half or more, especially at the entrances to private properties, so the water is blocked and will spill into the houses.