GUWAHATI, Jan 16 - The Northeast Frontier Railway today said its engineers recently carried out rectification of bearing arrangements on the old Saraighat Bridge during a three-hour exercise.
�Bearings are the arrangement by which the bridge rests on the piers or pillars. They not only link the bridge girders to the pillars but also facilitate the lateral movement of the bridge as a result of expansion. It was probably during the 6.1 Richter scale earthquake of September 2009 that the bearings under two end girders got tilted. While this was not considered unsafe, the bearings, in fact, needed proper rectification,� said Pranav Jyoti Sharma, Chief Public Relations Officer (CPRO) of NFR.
He said the bridge was kept under observation and speed of trains was kept at 45 km per hour for some time.
�Rectification of the bearings was a Herculean task as the ends of the bridge girders were to be lifted by about 10 centimetres. Such a work had never been taken up earlier. The team of Railway Engineers of NFR, after thorough research and design, decided that the tilted bearings of this bridge would be rectified. Accordingly, necessary preparations were made to deal with all kinds of possible adverse situations that could occur so as to avoid disruption to this vital connectivity. Requisite bearing members were arranged and heavy duty lifting jacks of 500 tonne capacity, apart from other machinery, were mobilised. To rectify the bearings without any hazard, the rail and road traffic on the bridge was suspended temporarily for three hours,� Sharma said.
Hydraulic and mechanical jacks were installed under the railway girders. With the help of these jacks, the railway girders were lifted as required.
�The bearings were removed from their place and installed back to correct inclination after cleaning. After ensuring correct position of the bearings, the bridge girders were lowered back to original position. Road surface was brought back to original level. Rail track was also re-fixed and regular rail and road traffic movement was permitted within three hours,� said the railway official.