Howrah Bridge

This is the miracle of engineering@@@

 While visiting Kolkata, Howrah Bridge tops the list of places to  see in the city. This Bridge attracts tourists for numerous reasons

• Howrah Bridge,Commissioned in 1943, is a bridge with a suspended span over the Hooghly River in West Bengal, India
• The bridge does not have nuts and bolts, but was formed by riveting the whole structure.
• It consumed 26,500 tons of steel, out of which 23,000 tons of high-tensile alloy steel, known as Tiscrom, were supplied by Tata Steel.
• The main tower was constructed with single monolith caissons of dimensions 55.31 x 24.8 m with 21 shafts, each 6.25 metre square.

It is thought to be the busiest of its kind in the world, with more than 100,000 vehicles crossing a day and more than 150,000 pedestrians pounding its walkways daily.

The Howrah Bridge is at risk of collapsing because the steel at its base is being corroded by human saliva.

Corrosion has also been caused by bird droppings.

• Pedestrians who have been chewing betel leaf, areca nut and slaked lime have been spitting on the bridge's steel hangers, causing them to weaken.

•  An investigation in 2003 revealed that as a result of prolonged chemical reaction caused by continuous collection of bird excreta, several joints and parts of the bridge were damaged. 

• As an immediate measure, the Kolkata Port Trust engaged contractors to regularly clean the bird droppings, at an annual expense of ₹500,000 (US$7,800). In 2004, KoPT spent ₹6.5 million (US$100,000) to paint the entirety of 2.2 million square metres (24 million square feet) of the bridge. Two coats of aluminium paint, with a primer of zinc chromate before that, was applied on the bridge, requiring a total of 26,500 litres of paint. 

On 14 June 1965 it was renamed Rabindra Setu after the great Bengali poet Rabindranath Tagore, who was the first Indian and Asian Nobel laureate.It is still popularly known as the Howrah Bridge