Officials of the Kolkata Port Trust (KoPT), which maintains the bridge, said they have decided to install fibre glass covers at the base of its 78 pillars to prevent corrosion of the hanger-hoods caused by indiscriminate spitting.
"Collective spitting by commuters after eating 'paan' and 'guthka' is having such a bad affect on the health of the bridge that the thickness of the steel hoods protecting the hangers have reduced by 50 per cent of their original size in the last four years," KoPT's chief engineer A K Mehra told PTI.
Explaining how the 705-metre-long cantilever bridge's longevity is being damaged as a result, he pointed out that the half-chewed betel leaves, areca nut and slaked lime spat on its base contain highly corrosive elements that erode steel.
"It is now affecting the stability of the hangers that transfer the load of traffic uniformly across the structure," he said.
The protective hoods at the base of the hangers prevent water seeping into the junction of the cross-girders and hangers.
As a temporary measure, they have already painted primer zinc chromate on the hanger-hoods.
According to a 2007 survey by KoPT, more than 1,20,000 vehicles and 500,000 pedestrians use the bridge everyday to cross the Hooghly river flowing between the twin cities of Howrah and Kolkata. (MORE)