Investigation on buckling of all-FRP bolted built-up columns

This study investigates the reliability of the buckling formulas usually employed for designing bolted built-up columns of pultruded fibre reinforced polymer (FRP) material. Several papers have been published on buckling and instability analysis of pultruded FRP columns, but the same studies do not deal with built-up type. In this case, it is necessary not only to take into account the effect of the high deformability of the FRP material, but also to clearly identify the extent of each element in the overall bearing capacity as well as in the type of connection - i.e. it can play a key role by increasing the axial stiffness or it may contribute to the shear stiffness. The investigation compares the results predicted by the existing formulas to experimental data as well as to an appropriate finite element analysis previously carried out. © 2014 © 2014 The Institution of Engineers, Singapore.