Title : REPAIR OF A TSUNAMI-DAMAGED LIGHTHOUSE AT LITTLE ANDAMAN
Authors : Devdas Menon
Publication : 13th – 16th February 2013
Volume :
Pages : 6-Jan
Price : 250
Abstract : The reinforced concrete (RC) lighthouse at Little Andaman Island, built during 1973-1980, was struck by the Tsunami/earthquake on 26 December 2004. This 45m high cylindrical tower was badly damaged in the lower portion, with extensive spalling and crushing of concrete and buckling of the vertical reinforcement on one side and yielding and fracturing of reinforcement on the other side (facing the sea), along with severe damage and tilting of the RC portico structure connected to the tower at the entrance. The Department of Lighthouses and Lightships sought the assistance of IIT Madras to explore the possibility of salvaging this lighthouse, as an alternative to the expensive option (recommended by an expert committee) of demolishing and rebuilding the structure. The paper describes the details of the repair and retrofit measures proposed by IIT Madras and successfully implemented at site. The remedial measures consisted primarily of concrete jacketing of the lower portion of the shell structure from outside and inside, with additional thickening on the outside (to correct the eccentricity in vertical alignment) and provision of additional vertical rebars, properly anchored to the well cap below and the undamaged portion above. The repaired lighthouse has safely resisted several high intensity tremors in the region, without any visible damage