A few days after a concrete slab fell from the Hero Honda Chowk flyover, cracks were noticed on two elevated U-turns and an elevated road at Iffco Chowk.
A few days after a concrete slab fell from the Hero Honda Chowk flyover, leading to a pothole in the structure, cracks were noticed on two elevated U-turns and an elevated road at Iffco Chowk.
Widening gaps between the slabs have posed serious question marks on the quality of construction and the engineering soundness of the structures.
The cracks appeared near two slab joints on an elevated U-turn from MG Road towards New Delhi that had been opened on a trial basis in November last year.
Similar cracks have appeared on an elevated U-turn constructed for commuters travelling from Sukhrali towards MG Road; this stretch has not been opened for trial yet.
“These structures are located on an expressway where speed limits are high. Under such circumstances, if a pothole or crack appears on the surface, it’s dangerous for two-wheelers as well as four-wheelers. They should be inspected on a daily or weekly basis by NHAI,” said Gurpreet Singh Thakur, road safety associate with Haryana Vision Zero, a programme to reduce road accidents.
However, National Highways Authority of India (NHAI) officials said these were not cracks at all, but gaps in slabs that needed to be filled.
Ashok Sharma, project director, NHAI, explained, “These are gaps between construction joints. A road-safety audit has been carried out, but the structures have not been issued completion certificates yet.”
Commuters, on the other hand, say the cracks are so wide that the road below is visible through them — and this happens just four months after inauguration!
A visit to the site revealed that these cracks were perpendicular to the construction joints, and were not, as NHAI explained “gaps between construction joints”.
Here’s what another NHAI engineer, who requested anonymity, had to say on the matter, “The cracks have appeared owing to a difference in temperature. The structure is absolutely safe.”
He explained, “The contractor had been directed to provide the best treatment possible to control the expansion and contraction of the bituminous concrete so that the aesthetic and riding quality of the structure were maintained.”
Getting into technical details, he said, “The two separate slabs on the flyover had different piers and pier caps. Keeping in mind the contraction and expansion of the material, a mandatory longitudinal joint had already been put in place. However, to maintain the riding quality of the road, a wearing coat [top bitumen layer] had been laid on the whole width of the deck, which did not fare well as the temperature rose.”
However, experts have their doubts.
Sewa Ram, professor, transport planning, School of Planning and Architecture, New Delhi, said, “The size, length and width of the cracks indicate a failure in both design and construction. The damaged area needs to be broken and recast. Other areas of the flyover must be tested as well. The flyover should be opened to the public only after it is tested for load capacity, quality of construction and design. Any heavy vehicle passing over the flyover right now will further widen the crack and turn the entire structure into a death trap.”
The structures were opened for traffic in November and December last year. The elevated flyover at Iffco Chowk has not officially been opened to the public yet, commuters have started using it.
In the words of Ram, “Sometimes, the structures are opened to traffic before time, and this premature opening can lead to cracks. Deflection tests are required to check the structures’ strength, so that weak portions can be repaired at the earliest.”
