The iconic Howrah Bridge was built without a single nut or bolt

Countries & Cities · Published 10 October 2026 Swipe more like this →

In short: Spanning the Hooghly River, this massive cantilever structure is a symbol of Kolkata. Completed in 1943, it relies entirely on rivets to hold its 26,500 tons of steel together. Despite its architectural ingenuity, the bridge faces an unusual modern adversary: the corrosive power of human spit and bird droppings.

The Howrah Bridge, officially named Rabindra Setu in 1965, serves as a vital gateway connecting Kolkata to the Howrah rail terminal. Its construction was a feat of endurance, delayed by the outbreak of World War II. When steel shipments from England were diverted for the war effort, Tata Steel stepped in to provide 23,000 tons of a specialized high-tensile alloy called Tiscrom. The bridge was erected by the Braithwaite, Burn & Jessop Construction Co. using a riveting process rather than nuts and bolts, a design choice that defines its structural integrity.

The foundation work was equally complex. Workers sank massive caissons deep into the riverbed, reaching stiff clay at depths of over 26 meters. The process was so intense that at one point, the ground shifted, triggering a local seismograph and destroying a nearby temple. Once completed, the bridge became the third-longest cantilever span in the world. Today, it remains the sixth-longest of its type, carrying a daily load that far exceeds its original design capacity of 60,000 vehicles.

Maintenance is a constant struggle for the Kolkata Port Trust. Beyond the stress of heavy traffic, the bridge suffers from chemical damage. Bird excreta and the acidic, lime-mixed stimulants found in local paan and gutka have caused significant corrosion to the steel hoods protecting the pillars. By 2011, inspections showed that spitting had thinned these protective layers by half. To combat this, the authorities have implemented measures ranging from fiberglass casing for the pillars to high-tech surveillance cameras, ensuring this historic structure continues to serve as the heartbeat of the city.

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