Investigation of the Flexural and Buckling Behavior of Concrete Filled Steel Tubes (CFST) Columns in Bridge Piers

Nowadays steel-concrete composite members have successfully been used in pier، beam and deck of bridges، and column، beam and slab of high-rise buildings. Due to their considerable energy absorption and dissipation capacity، concrete filled steel tubes (CFST) members have gained popularity in bridge and building construction. Composite members not only have many advantages in the structural construction but also make a significant improvement in the behavior of structure compared with reinforced concrete and steel structures. Some of these advantages include: Easy and fast for erection and fabrication، using standard connection، savings in the construction costs، suitable performance against seismic loading، high loading and ductility capacities (with fewer volume). In this study، efficacy of type، number and location of two stiffening methods have been investigated on the flexural، buckling and ductility behavior of composite columns. It was found that stiffener enhances the ductility، absorbing energy، strength and critical buckling load of composite columns in comparison to columns without stiffeners.