Structural remediation & retrofit of distresses precast-prestressed 'T' beams of a public utility building, in Colombo, Sri Lankla – a site case study

Abstract

The roof slab of a portion of a government public utility building situated in Colombo, Sri Lanka, comprises of precast – prestressed ‘T’ beams. There was a huge fire in this building and during the subsequent refurbishment of the building it was noted that the majority of the ‘T’ beams at this area were exhibiting distresses in the form of cracks. A thorough investigation conducted by the concerned authorities in conjunction with the University of Moratuwa concluded that the structural distress was due to event overloading onto the roof slab during the fire fighting operations. It was also concluded that a requirement of certain remediation and retrofit\ measures to the distressed elements were necessary to bring the ‘T’ beams back to their intended service performance level. This paper describes in detail the site case study of the repairs and retrofit that was carried out to achieve the desired design objective. Repairs to cracks were carried out using multi-port, low pressure resin injection, the retrofit was carried out using the Carbon Fibre Reinforced Polymer (CFRP) system, thus resulting in a quick, discreet and cost effective way to meet the design objective.