The bridge that collapsed recently in Gujarat’s Morbi killing at least 134 people, was a suspension bridge.

 

About the ‘Suspension Bridges’

  • Suspension bridge is a type in which the deck is hung below suspension cables on vertical suspenders.
  • The basic structural components of a suspension bridge system include stiffening girders, two or more main suspension cables, and towers and anchorages for cables at either end of the bridge.
  • The main cables are suspended between the towers and are connected to the anchorage or the bridge itself.
  • The vertical suspenders carry the weight of the deck and the commuter load on it.

 

Working

  • The design ensures that the load on the suspension cables is transferred to the towers at the two ends, which transfer them further by vertical compression to the ground by way of the anchorage cables.
  • All of this balancing has to happen within the permissible weight restrictions for the bridge, given that the deck is hanging in air, supported by the two sets of cables.

 

Why suspension bridges are preferred?

  • The reason for the enduring design of the suspension bridge is that the supporting cables running horizontally between the two far-flung anchorages.
  • This provides the counterweight and effectively pass on the entire tensional force to the anchorages.
  • As a result, suspension bridges can easily cross distances of well over 2,000 metres, beyond the scope of other bridge designs.

 

What could have happened in the Morbi bridge collapse?

  • The most important load bearing members are the main suspension cables.
    • The entire cross-section of the main cable is the mainstay of carrying the load and ensuring that buckling does not happen.
    • But this is subject to two preconditions: there must be no overloading, and no excessive swaying.
  • Even as an investigation into the accident is pending, the visuals and purported footage prior to the incident seem to suggest that:
    • The 19th century bridge, which had been reopened recently after repairs, reportedly had over 400 people on it when it collapsed.
    • Also, the video footage from before the incident seems to suggest the bridge was swaying, possibly because of the large crowd on it.

 

About Morbi

  • Morbi is a major hub of small and medium industry and India’s ceramics factory.
  • The more than a century old bridge across the Machchhu river has long been a major tourist attraction.
  • Morbi district was created on August 15, 2013, along with several other new districts.
  • This district is flanked by Kutch district in the north, Surendranagar district in the east, Rajkot district in the south, and Jamnagar district in the west.
  • Ceramic industry —
    • Morbi is famous for its ceramic industry.
    • The district is dotted by several hundred ceramic producing factories, mainly medium and small scale units.
    • Around 70 per cent of Indias ceramics are produced in Morbi, and ceramic tiles manufactured here are exported to countries in the Middle East, East Asia, and Africa.
    • The major competition to the Morbi ceramic industry comes only from China.
  • Machchhu —
    • Machchhu is a small river that rises in the Madla Hills and flows 130 km into the Rann of Kutch.
    • In 1979, a major tragedy occurred after a dam on the river failed, inundating Morbi town and killing a large number of people.
  • The ‘Jhulto Pul’ on the river —
    • The suspension bridge, “Jhulto Pul”, was a pedestrian suspension bridge that was inaugurated in 1879, during the reign of Sir Waghji Ravaji, the Thakur Sahib of Morbi (1858-1922).
    • Sir Waghji is credit with planning and building the entire city of Morbi, which included India’s first art deco palace, and a European-style central square known as Green Chowk.