Restoration of Cold Storage Factory Building

Abstract

This paper deals with the renovation of a factory building in Nellore, India. The plan dimensions of this building are 25.7 × 52.5 m. It has concrete columns and the roof is made up of Pratt trusses with hot-rolled steel sections. Because the building is used as a cold storage facility, it is covered with a 130-mm-thick slab, which consists of the following four layers: (1) Roladeck trapezoidal sheeting; (2) one layer of 50-mm-thick concrete; (3) a layer of 40-mm-thick polyurethane foam; and (4) another layer of 40-mm-thick reinforced cement concrete (RCC). A significant amount of deflection was noticed when the scaffolding for the concrete was removed. The reason for this deflection was that most of the members of the trusses were overstressed due to the error of assuming that the truss would support traditional asbestos concrete sheet roofing. The rehabilitation measures included welding of additional steel plates to the members of the trusses. Proper precautions were not taken during welding repairs, which resulted in local buckling of the main members of the trusses. This buckling was mainly due to implementing the welding of the extra plates without providing temporary supports for the trusses, which were already carrying heavy loads. Finally it was decided to introduce intermediate columns that will reduce the force in some truss members. These remedial measures are discussed.