Comparison of Seismic Performance Improvement Techniques of End Plate Connections through Intentionally Weakening of Beam

In some cases, such as provisions changes in new code or even changes in the structure performance of the building, it may be probable that the component thickness of end plate steel frame connections does not qualify related regulations. In these conditions, there is a need to improve the performance of the connection for preventing the plastic hinge from occurring at the steel column face. For this purpose, two general techniques are accessible that include intentionally weakening the beam through “reduction” and “annealing”. The latter process is a heat induction technique meant to reduce the yield and tensile strength of steel. The current research is about to compare these two techniques and address the parameters influencing the performance of “the enhanced connection”. For each technique, four specimens having end plates with different thicknesses are considered. It is concluded that the heat induction technique was preferable in terms of energy dissipation, moment capacity, local buckling of beam and torsional stability. It should be noted that both techniques were successful in shifting the plastic hinge action away from the column face for the endplate connections with a maximum decrease of ۱۵ mm in the endplate thickness. Moreover, eight numerical models were investigated to compare the “heat induction” and the “reduction” techniques sensitivity to temperature of the weakened and width of the trimmed region respectively.