Barak bridge develops crack, traffic affected

 SPECIAL CORRESPONDENT

 SILCHAR, April 10: The Barak Bridge on the northern fringe of this town is again in trouble. This is not a new phenomenon, but a continuation of its old problem since its inception. It is difficult to say how many times the bridge has undergone repairs, poking hole in the public exchequer. The identified trouble spot has again developed problem and the PWD (NH) has taken up necessary repair work. The question is how long this process of damage and repair will continue. From this morning, traffic movement through the bridge has to be restricted.

 It is to be recalled that in the past the bridge has developed cracks, raising question about its sustaibility. The bridge connects Manipur, Dima Hasao district and the airport, besides being a passage for the cluster of villages of Borkhola and Udharbond constituencies of Cachar. It also provides link to NH 53 and NH 54, an access to Mizoram and Imphal. It is also of strategic importance. The bridge was constructed by Gammon Company in 1967 which has been requiring constant expert intervention for smooth functioning. Looking at the frequent spending of public money on its repair, it is also sarcastically called ‘a Kamdhenu’ bridge.

 Continuing problems have caused apprehensions in common and commuting people about the sustaibility of the bridge. Public agitations from time to time have been for repair and improvement. Giving technical details of the bridge, a senior engineer of PWD (NH) division said the 472 metres long bridge has 17 spans. Out of these 12 are of 15.86 metres each, 2 of 23.48 metres each, 2 others of 56.40 metres each and the 121 metres long middle portion of the bridge stands on cantilever.

 From the record, it is clear since the construction of the bridge, some major defects were observed in the balance cantilever of 121 metres. Abnormal deflection at the tips of the cantilever arms was noticed. Central cantilever portion was repaired in 1990. After a decade, problem occurred in the central hinge portion of the cantilever that was rectified by providing a 10 metre long timber-bridge over the cantilever hinged joint portion to maintain flow of traffic. Apart from that, cracks were noticed on the main cantilever arms that were repaired by epoxy grouting and by providing exterl stressing of the cantilever in a small portion at the support point in 1999. The condition of the bridge necessitated restriction on traffic movement, limiting it to 25 tons only, which continued to be observed more in breach than in compliance.

 Owing to the overloading, as pointed out by the senior engineers, all the concrete bearings of the 12 spans were damaged. Deck-slabs in all small spans also got damaged. In view of the deteriorating condition of the bridge, NH division prepared a comprehensive rehabilitation package of Rs.660.54 lakh with a recast for Rs.196.60 lakh to the Union Ministry of Surface Transport which allotted Rs.173.3 lakh to the department. The repair and rehabilitation work was assigned to the German consultancy firm Fressynet Prestressed Company.

 The German firm started the repair and improvement work with all the modern know-how and expertise. This included repair of damaged RCC component and the desk-slabs, replacement of bituminous wearing coat and preparation of asphaltic wearing coat. Replacement of damaged RCC bearing blocks with elastomeric and pot bearing, damaged expansion joint with ship seal joint, repair of beam at supports with structural strengthening with carbon fibre also formed part of the improvement work.

 Along with that was carried out epoxy grouting for 12 spans and repair of handrail and painting the surface. Rehabilitation of cantilever portion in the central span with 121 metres was done by providing exterl prestressing to regain the stress loss as well as the restoration of central hinge. But, despite all the remedy, the bridge has to undergo round the year repair. With that the woes and worries of people go on. Quite significantly, it is perhaps the only bridge in the state that was thrown open to traffic by people themselves without waiting for politicians to flag off.