Structural Repair and Rehabilitation of 3 no. (G+8) Multi-Storeyed Residential Buildings, at ONGC Colony at Chandkheda, Ahmedabad, Gujrat

Abstract

Abstract Although reinforced concrete structures are designed as per codes/standards but enough care is not always taken during construction process. As a result, the structures start showing signs of distress, some times less than 10 years of service life, requiring early repair and rehabilitation work. In this paper, a case study of 3 no. (G+8) multi-storeyed buildings badly damaged due to corrosion and Bhuj (India) earthquake of 2001, rehabilitated in 2003 has been presented. Repair strategy involved removal of delaminated carbonated concrete cover, application of rust remover, anti-corrosion coating, polymer bond coat, polymer modified mortar, injection of low viscosity epoxy grout to beam-column junctions and cracks, repair of masonry cracks with polymer modified mortar & grouting with SBR modified cement grout and jacketing of columns at the ground floor. Extensive material testing was carried out and specifications for acrylic and SBR polymer modified mortar were selected for durable repairs. Strict quality control and assurance both in material and workmanship was adopted. After nine years of successful rehabilitation and functioning, some signs of distress in the form of cracks and spalls due to rebar corrosion have been noted at some locations, requiring rehabilitation again. Some recommendations/conclusions have been given for durable concrete constructions and rehabilitation work.