ANALYSIS OF OSCILLATIONS OF A TWO-STORY FRAME UNDER BEYOND-DESIGN IMPACT

The article presents mathematical models of oscillations and an algorithm for calculating a discrete dissipative system (DDS). The algorithm is based on the following condition: the structural element is disabled due to an out-of-design load. According to the theory of time analysis, the resolving equations of the reaction of a structurally nonlinear system are written for two states: before switching off the carrier element (at t <= t1) and after switching off (at t > t1). The article considers the oscillation of the model of a 2-storey reinforced concrete frame building during the destruction of the corner column of the lower floor. The destruction of the column occurs as a result of an accidental impact of a vehicle. The oscillograms of fluctuations in the dynamic reaction parameters of the models are given: the basic (initial) model (BM) and the damaged model (PM). The oscillograms of accelerations and force parameters of the PM reaction at the time of column extraction at t1 contain sharp changes in values (jumps). A jump effect was found for the vector of external dynamic forces as part of the torque of the 1st floor of the PM. It occurs as a result of a change in the position of the coordinates of the center of rigidity (c.w.) of the overlap at the time of the sudden removal of the column.