Site Report: Wave Silver Tower, Noida, India

India's economic boom is seeing the residential and commercial real estate markets take off. The astonishing growth in this sector is particularly evident around the capital, New Delhi, where the surrounding towns and cities are merging into the conurbation as new transport links are built and people migrate to the area.

The prime plots of land are of course those with the best transport links, and the expansion of the Delhi metro to surrounding towns and cities is helping to drive redevelopment.

This is very much the case in Noida, a fast-growing city of a few hundred thousand people some 20 km to the southeast of Delhi. The end of last year saw a branch of the Delhi metro opened in the town

The Wave Silver Tower development is being built in a prime location next to the central metro station, a location that should serve this 13 storey office and shopping development well. But the proximity of the line - just 20 m at its closes point - the small footprint of the site, difficult ground conditions and the need to complete the project quickly are making it a challenging and dynamic scheme.

The project is being developed by the Chandra Group, a diversified Indian conglomerate, with contracting work being carried out by what is essentially an in-house contracting division. For the purposes of this project, a separate entity was set up to carry out the work - Wave Silver Tower Pvt Ltd - with some investment from outside companies.

Completion of the project is scheduled for February 2011, a timescale that would be difficult with traditional Indian construction techniques that rely heavily on manual labour. Instead the contractor invested in an MCI 85A Potain tower crane, and there is very little on the site the machine is not being used for. As well as handling rebar, formwork and a concrete skip for the construction itself, it has also played a crucial role in the excavation work.

With three below ground floors and an excavation depth of 11.8 m, this involved moving a total of 250000 m3 of material. This was dug by hand, and then loaded into a bucket, which was then lifted out by the crane.

Ground conditions are challenging at the site. The sandy soil has required extensive reinforcement, and great care had to be taken along one side of the building to avoid undermining a neighbouring office building. The ground was reinforced with steel I-beams sunk to a depth of 16 m. A coarse steel mesh was then laid over the exposed face of the excavation and shotcrete applied. Once again the crane came into play, with the concrete being sprayed by a worker from a man basket suspended form the crane.

Despite these measures it has been a challenging part of the project as Deputy Project Manager JHA Subhash explained, "Sand collapses have been the major concern. We protect against that with steel shoring and shotcrete."

When iC visited the site in March, the tower had reached ground level, with the structural parts of the three basement levels all but complete. The building is using standard Indian building techniques, with floor slabs and columns being cast in-situ to establish the frame, and all walls being filled-in later with hand-laid bricks.

The tower has a footprint of 23 m x 97 m, with the columns on a more-or-less square grid at 5.5 m centres. The only break in this pattern is a 21 m wide atrium in the centre of the long side. In addition there is a 150 mm expansion gap through the centre of the building, which is required by Indian building regulations every 45 m.

The final height of the building will be 63 m, with the crane going up to 70 m

Crane choice

It would be difficult to overstate how heavily the contractor is relying on its Potain tower crane for this project. Apart from the crane, the only other equipment on site are two generators - one of which is a 125 kVA supply purely for the crane, a Schwing trailer pump for pumping concrete and an agricultural tractor to haul material around.

The procurement of the crane was handled by another Chandra group Company, Infra 13, so iC spoke to its hear of procurement, Vineet Jayee about how it made the choice of Potain.

"We had a detailed discussion and we considered 45 key points. Potain was supplying the crane from India with their service back-up, and that was important They're very technically sound and they can solve our queries. They are also very high quality," he said

Mr Jayee added, "The crane is working 24 hours a day because we have to hit certain deadlines. We haven't had any serious problems.

"If I had any doubts about the support I wouldn't have placed the order. It is one of the most important things when you're investing this much money. If this tower crane didn't work out we would have missed out deadlines as well as wasting our money."

Indeed, this is the first tower crane the company has ever bought, so such a thorough and cautious approach is perhaps to be expected. But with the site working around the clock - 7 days per week with two 12-hour shifts - it is difficult to see how the scheme could have been completed on time without it just using manual labour.