Bridges

When it comes to bridges, safety and strength are crucial. But most people’s first reaction to a bridge is based on the aesthetic value. Driving down to Madgaon from Panji in Goa, your jaw drops as you pass the spectacular Zuari Bridge, the longest in that state, at 1,320 metres. Crossing the Sharavati river near Honnavar, the waves surge and gush below you; it is only two km. later that you are back down to earth. On the Konkan Railway route, this one is the longest bridge; in a project that has 2,000 bridges across deep valleys and wide perennial rivers, thiws is quite a distinction. On the Veer-Khed section alone, a distance of 52 km., there are 14 major bridges, 10 road under bridges and 145 minor bridges. Other important river crossings are across the Vashishthi, Shastri, Mandovi, Kalinadi and Halladi. Between Bhatkal and Mangalore, there are 29 major bridges.

Click on image for big view
a blue train	Mandvi Bridge	Panvel Brdge
a road under bridge	on Sharavati River	on Jagbudi River
Kundalika Bridge Veer Dasgaon	Nandivli Bridge	Mangalore-Udipi Section

With so such to be done in so short a time, it was imperative that designs of viaducts and piers be standardised. For the piers, two types of cross sections – hollow rectangular and hollow circular – were selected. The circular section was selected for viaducts crossing river streams with possibilities of high floods so as to minimise the waterway obstruction and allow for square type of bridging arrangements even in situations where the railway alignment cuts the streams obliquely.

The strategies conceived to economise viaduct construction comprised adopting relatively shorter spans and at the same time optimising the design of the tall piers. The span lengths range from 20 metres to 30 metres and the height of piers from 20 metres to 45 metrers.The use of hollow reinforced concrete piers (400 mm. wall thickness) built by the slip forming technique meant speed of construction, economy in materials and better performance under seismic excitations.