Flexural Behaviour of Retrofitted Steel Hollow Section Beams in Offshore Application

In civil engineering applications, hollow section beams are extensively used mainly in
the construction industry and offshore structures. After several years of usage, the
structures undergo damage and suffer corrosion thus requiring regular maintenance. The
main purpose of this study is to determine the flexural behavior of high strength concrete
filled steel hollow section beams in offshore applications. Two methods have been
identified to rectify this problem which is infilling with concrete in the steel hollow
sections and another method of using Carbon Fibre Reinforced Polymer (CFRP) is also
introduced in this study. The CFRP plates are applied at the outer sides of the steel
hollow sections. Experiments were done to study for the flexural behavior of the steel
beams that is being retrofitted by infilling with concrete and applying CFRP plates. A
total of twenty specimens were prepared and tested for different types of hollow
sections, concrete grades and CFRP. The flexural behavior of the specimen is studied
when the beam is under one-point loading. Results from this experiment showed that the
concrete used in the specimen together with the steel hollow sections does increase the
flexural capacity of the beam itself. Results from applying CFRP plate at the sides of the
steel hollow section showed an increase on the overall moment strength