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Fastest dome roof concreting record at Chhara

Afconians write a new chapter in Extreme Engineering & Construction by finishing concreting in just seven-and-a-half days

The Chhara LNG project team’s latest milestone is a defining moment for Afcons. The team completed concreting of the dome roof at Tank 102 in just seven-and-a-half days, a record for both Afcons and its Japanese consortium Partner, IHI Corporation.

“Our achievement is a remarkable example of Extreme Engineering & Construction. The critical activity involved 2717 cum of concrete to be cast across nine stages at 50m height in spherical shape in 15 days, as was agreed by IHI-Afcons consortium. We completed it in half the agreed time,” says Project Manager Lokesh Nayak, who steered his team to success.

The meticulous process involved casting the tank roof slab on a structural steel dome weighing about 450MT, which was airlifted from the base slab using air blowers by IHI. During concreting, the dome structure was supported with air support for additional stability. While this took place, all mechanical activities inside the tank were suspended as hot work (welding, cutting) cannot be done in pressurised confined space. The team relied on experience to ensure the process was completed smoothly as well as in a realistic timeline.

“At Afcons’ Dahej LNG Tank project, roof concreting was carried out in seven stages, and it took us 21 days and 15 days for Tank 106 and Tank 105, respectively. Based on experience, we realised that the delays were mainly due to manpower productivity, pipe choking, slump loss and delay in construction of joint cleaning,” elaborates Nayak.

The team had to factor in several constraints, including concrete supply rate and manpower productivity. Also, concreting at a height of 50m on the top of a massive dome shape structure is very hazardous, it was difficult to work on steep slope and accordingly due safety measures were taken. To ensure maximum productivity, a highly-skilled team was divided into six smaller units that would function round the clock. “We took the decision of using three concrete pumps as anything lesser would have compromised our targets. As precaution, a man basket was kept on standby for evacuation and arrangements were made to provide immediate access by removing the concrete pump,” says Nayak.

Just as the team was raring to go, Gujarat coast was hit by unseasonal rain. “Instead of being disheartened, we chose to look at the bright side. We were well prepared and determined. We also had the advantage of an additional tower crane,” he adds. Concreting was done using three concrete pumps and three crawler cranes. Occasionally, three tower cranes were deployed to operate six buckets to achieve 15cum concrete pour rate. This isn’t the first hurrah moment for the team. At Tank 101, a similar activity was completed in nine days.

This achievement only reinforces Afcons’ dominance in India’s LNG infrastructure construction. The Shapoorji Pallonji Group company has constructed six operational LNG Tanks – four in Dahej, Gujarat, and two in Kochi, Kerala. “With the world consciously shifting to green energy, boosting LNG facilities is crucial. Our achievement is a major step for Afcons, IHI Corporation as well as India,” Nayak concludes.

This new achievement reinforces Afcons’ leadership in LNG space in the country.

Watch a short video of the achievement

Charra LNG Tank project
Charra LNG Tank project
Charra LNG Tank project