Napier: India’s first pre-stressed concrete bridge

The bridge that linked two fine-looking parts of the seafront promenade was initially done to the efforts of Lord Napier.

Most other spots on the river Cooum had been already forded but there was no bridge near the mouth of the river prior to 1868.

People could not even wade across the Cooum as currents, eddies and quicksand occasionally took their toll in human lives. The tidal action made even crossing on boats too dangerous at this spot. And the same forces of nature refused to allow a bridge to be built.

In 1868, Lord Napier decided on one more bridge from the fort area. He had his men sink cast iron screw piles into the river bed and an iron lattice bridge made to stand on them. Railings protected the sides. But sea air has this corrosive ability to rust the iron and erode man’s labour and by 1909 the bridge was as dangerous to cross as the quicksand below.

In 1909 the bridge was replaced at the cost of 3.75 lakhs with iron girders on the side. A great pride at that time was that the bridge from the girders down to the last rivet was locally manufactured. With all the iron, lightning was striking the bridge quite too often and one of the earliest lightning conductors in the country was established on the north east corner and still stands.

But once again the sea was at work and the new bridge eroded in a decade or two. The last alternative was a concrete bridge which would give some permanence.

In 1939 the city council sat on the proposal. A project costing 1.5 lakhs was unthinkable in the world war days, especially not knowing which way victory would smile.

But then members were worried that the bridge would collapse at any moment and more so in the case of a storm. And it would look unhealthy on a city at war as it would cut off the secretariat from the rest of the city. They had to take it up on an urgent basis.

A string girder bridge with vertical hangers was decided upon. It was a tied-arch system which in engineering terms directed outwards the forces on it, rather than to the ground or the bridge foundations.

The elimination of horizontal forces at the abutment allowed tied arch bridges to be constructed with less robust foundations as what the Cooum offered near its mouth.

The bridge would be 489 feet long and 56 feet wide and would swallow 240 tons of steel and 500 tonnes of cement. This was the first prestressed concrete bridge in India.

The bridge was awarded to Gannon Dunkerley & Co, a major construction company at the time, doing bridges airstrips and hydroelectric projects. The other project in pipeline at the time was the Tirupathi Thirumala Ghat road.

The bridge work was supervised by the Madras Port Trust on behalf of the government.

After the estimates were approved by the PWD, dismantling of the earlier bridge went on for a year before work stopped due to war related evacuation. When it was commenced again, Governor Hope decided it would have to be done well this time and even visited the site unannounced many times to stress on its importance.

The bridge was opened by the Governor of Madras on July 9th 1944. Mentioning how difficult it was to procure so much material in war-time, His Excellency declared the new bridge open hoping it would last longer than its predecessors. He joked it would be easier for people to get faster to the city and on a personal front he himself could save a few minutes getting to the office in the fort and badger its inmates for that much longer.

Gannon, Dunkerley & Co charged Rupees 1.75 lakhs as an overrun cost but the city and the Government were very appreciative of the job done. 

Charles William Spencer, Manager of the firm was made an Officer of the Order of the British Empire and the company was mentioned in the King’s birthday honours 1944.

The well built bridge still stands strong just like the Tirupathi Ghat road and Indians have only doubled both of them.