LARGE PLASTIC DEFORMATION OF A STRUCTURE DUE TO IMPACT -AN EXPERIMENTAL STUDY ON A PORTAL FRAME SUBJECTED TO GROUND SHOCK, REPORT NO. 1

An experimental study is made of large permanent deformation of the columns in a portalframe under horizontal impact loading. The column specimens are made of mild steel, alu-mmum alloy and copper plates. The impact load is applied, by means of a bifilar pendulum, as a large acceleration for a short period. The applied initial velocity at the base of columns ismeasured by the accelerometer, which was calibrated beforehand from load cell readings. Theexperimental results show a general consensus with the analysis which approximates the framerestoring-force characteristies to be hi-linear with a positive slope followed by a negative.