IMPHAL, Nov 7: Recently an accident occurred in Arunachal Pradesh at Seppa in East Kameng district. A 50 meter long suspension bridge totally collapsed when over 60 people climbed on it to collect a particular type of edible insect which appears at this time of the year. Luckily a boat was in the river which had come in handily in rescuing several people. However, 14 people went missing and 3 dead bodies were recovered by rescue teams. To avoid such accident which occurred merely due to the lack of knowledge of local people firstly we should know about suspension bridges and after that spread awareness to avoid such accidents on suspension bridges.
Suspension bridges are one of the earliest types of bridges developed by man. Simple suspension bridge for use by pedestrian and livestock are still being used using design based upon the ancient times. These bridges are made up of towers and a bridge deck that is support by cable made of steel nowadays. Due to low cost and ability to be used over waterways and deep gorges, these bridges have been extensively used in hill areas connect villages across rivers, streams and gorges.
As regards to safety precaution on use of suspension bridges, following points must be adhered to prevent any miss happening due to bridge collapse.
(i) Suspension bridges are flexible structures that are designed to sway with the wind. However, due to their lightweight nature, they may sway too dangerously in extreme conditions and area unsafe to use until extreme weather passes.
(ii) Regular maintenance and inspection of bridge parts cables, decking and towers is essential as small flaws have been known to collapse the bridge.
(iii) Each bridge is designed for particular type of load. It is essential that unauthorized loading of bridge is prohibited (eg- pedestrian bridge should not be used for vehicle move). Some boards mentioning this should be there on both of the bridges.
(iv) Maximum load carrying capacity of the bridge should be clearly displayed at both ends by the manufacturer and same should not be violated. For pedestrian bridge, maximum number of people at one time should be clearly displayed.
(v) For extra safety use of safety nets under the bridge is recommended. In past these nets have served many lives in case of accidental failure of decking or someone falling off from bridge.
(vi) Due to very simple design and low cost there are no added or secondary safety features in suspension bridge. If one member fails the complete structure fails. It is recommended that state agencies provide additional safety net below the bridge especially in high use areas top prevent mishaps as one under ref. If not permanent the same may be fixed during festivals etc. this would have saved all these lost lives.
(vii) Daily commuters should note any breakages, deformation, crack or rusting etc of the bridge parts as a habit and report immediately if found any. In case of any damage found to bridge it should be immediately closed to traffic till repairs is done.
(viii) Suspension bridge normally sway and make sound when one is moving on them. People moving should not panic and run which may lead to serious accidents.
(ix) Bridges serviceability and durability tests must be regularly conducted by responsible agencies and corrective measures taken to ensure safety of users.
(x) Due to non-rigid structure people should move closer to centre line of deck and not at sides. At no time should the deck be loaded on one side only which may cause twisting of bridge deck. Also no one should hang, hold or rest with suspender cables holding the deck.
With these simple safety precautions accidents can be prevented on suspension bridges.
Read more / Original news source: http://kanglaonline.com/2011/11/advisory-on-use-of-suspension-bridges-issued-by-assam-rifles/