Strengthening of steel-concrete composite girders using various advanced composite materials

The need for strengthening bridges is rapidly growing worldwide. In this research work, experimental and analytical studies were conducted to investigate the effectiveness of using various composite materials and techniques for strengthening steel-concrete composite beams.; The experimental investigation consists of two phases. In Phase One, beams were strengthened in flexure with different composite materials externally bonded to their steel bottom flange. All the strengthening materials used are proved to be efficient in increasing both the yield and ultimate load.; In Phase Two, the tested beams to failure in Phase One were cut into half and re-tested with the previously applied flexural strengthening. Yet, due to the relatively smaller span, hence higher shear forces, stud shear failure occurred close to the supports. Therefore, a new strengthening technique for horizontal shear was introduced to prevent the stud catastrophic failure.; ANSYS 5.4 finite element program was used for modelling the complete behaviour of the beams before and after strengthening; this model can be used by designers to predict the behaviour of the strengthened steel-concrete composite beams. The beams' behaviour in terms of load-deflection response was well predicted and was validated using the experimental results.