Analysis of structural-nonlinear vibrations of reinforced concrete frame

The article presents a physical law, 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 dis-abled due to an out-of-design (shock) load. Within 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 internal friction of the material is taken into account on the basis of the theory of elastic-viscous resistance in accordance with the model of disproportionate damping. 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 (sudden) impact of a vehicle. The oscillograms of fluc-tuations 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 extrac-tion 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.