Steel structures from post-independence industrial plants are 30-90 years old and corroded beyond replacement. A case study of a 40-year-old plant shows how concrete jacketing and encasement can restore columns and connections without shutting down operations. Tata Consulting Engineers has rehabilitated structures up to 95 years old, saving assets worth crores of rupees.
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Many industrial plants were constructed post-independence, most of which are under operation even after expiry of the service life. Most of these buildings are made of structural steel. The age of the buildings are more than 30 years and even may be as high as 90 years. Many of such buildings are subjected to severe exposure due to nature of functionality and are situated at remote locations. Steel, as we all know, is prone to corrosion and require maintenance. But due to aging, severe atmospheric and functional exposure, and poor maintenance, many structures deteriorated severely and pose a threat to safety. Shutting the plants and construction of new structure with new equipments, utilities, etc. is often not a viable solution on account of scarcity and high cost of lands, regulatory guidelines, and most importantly, huge loss of revenue. Hence, restoration of the structures to a safe and serviceable condition is the only alternative available to the engineers. Restoration or rehabilitation work needs an in-depth understanding about behavior of structure. It is also very important to inspect the site thoroughly to assess the constructability availability of construction materials and equipment and other resources while planning the various engineering alternatives. Here is an example of a planned building about 40 years old and height around 35 meters. The planned dimension of the building is around 40 meter by 50 meter. The building is in very bad condition, as you can see from the following exhibits. The engineering for rehabilitation of this building called for thorough inspection and mapping of the distress. Elaborate planning and evaluation of various alternatives, innovative concepts, and safe constructability. The criticality lied in the restoration of columns and connections without any interruption to the plant operation. The tangible and intangible benefit out of the rehabilitation is immense and runs into crores of rupees. As can be seen from the principles of rehabilitation, the steel building turned into a quasi-RCC building by means of concrete jacketing, encasement, and corbels. Self-compacting concrete has been recommended for ease of constructability. Challenges for the rehabilitation work are non-availability of construction drawings of the buildings, workforce having required level of skill, site approaches, and most importantly, the work methodology should be such that the plant shutdown can be avoided or restricted to minimum duration. Tata Consulting Engineers has completed a number of major rehabilitation of structural plant buildings aged even up to 95 years of old and working on a number of domestic and international projects offering innovative and comprehensive solutions. It is a way towards a sustainable solution and conserving the valuable assets and land. Pshh.
