An analitycal model for the prediction of the resistance of T-stubs with four bolts in a row

The paper is devoted to the experimental and theoretical analysis of T-stubs with four bolts in one row. In particular, the work focuses on an experimental pro-gramme carried out at the laboratory of the University of Coimbra, whose main results are used both to set up of a finite element model (FEM) in ABAQUS and to develop a theoretical model for the prediction of the T-stub plastic resistance. Within the experi-mental activity three specimens, designed in order to reproduce the typical T-stub fail-ure modes, have been tested. Starting from the obtained results a finite element model able to reproduce the T-stub non-linear behaviour has been carried out in ABAQUS software and its accuracy has been verified by comparing the experimental and the simulated force-displacement curves. Aiming to carry out a simplified analytical model for the prediction of the re-sistance of T-stubs with four bolts in a row, two steps are needed: the effective lengths for all the failure mechanisms have to be determined and a formulation for the predic-tion of the T-stub resistance has to be defined. Therefore, in a first phase, the analysis of the yield line patterns arising in the flange plate has been carried out in order to indi-viduate the yield line families for all the possible failure mechanisms. Afterwards, by following the classical procedure for defining the effective lengths, the work due to the external loads and the internal work of the hypothesized yield lines has been equated in order to determine the effective lengths of the equivalent T-stub in tension. Finally, a general formulation able to provide the resistance of T-stubs with four bolts in one row has been developed and its accuracy has been verified on the results of a parametric analysis carried out in ABAQUS software