Innovative joint configuration for structures subjected to highseismic actions and to exceptional events - Development of aspring model reflecting the joint behaviour in case of a columnloss scenario

Abstract

Structures made of steel have been widely used in areas where seismic activity is expected in the last decades. Their stable performance under cyclic loading conditions make them a desirable solution in earthquake prone areas. However when subjected to exceptional seismic events, like several times in the past, the fact that the input energy is dissipated by deformation of structural elements leads to severe damage and consequently high repair cost. In order to overcome the above mentioned drawbacks innovative beam to column joint had been designed.This innovative beam-to-column joint is equipped with friction dampers which are located at the bottom flange level of the connected beam to dissipate the earthquake input energy. The friction resistance is calibrated by acting on the number and diameter of bolts and their tightening torque governing the preloading. The connections are conceived to exhibit wide and stable hysteresis loops without any damage to the connection steel plate elements. The objective of the dissertation is to study the behaviour of a frame and the innovative joint forming the framewhen subjected to a column loss.In case of column loss scenario, this joint will be subjected to a specific loading (bending moment + axial loads) which will require the activation of ductile joint components to allow the activation of an alternative load path within the structure. Within the thesis the behaviour and potential benefits of the joint under mention circumstances shall be assessed and pointed out.