PARAMETRIC NUMERICAL STUDY OF THE POST-ACCIDENT STATE OF A REINFORCED CONCRETE FRAME BUILDING UNDER LOCAL DYNAMIC IMPACT

Abstract

The article presents the results of a control parametric numerical experiment aimed at assessing the post-accident state of a reinforced concrete frame building after a local dynamic impulsive impact. The relevance of the study is determined by the need for rapid and quantitatively justified decisions on access to damaged buildings during search and rescue operations. The purpose of the research is to establish patterns of change in the post-accident state of a spatial reinforced concrete frame building depending on the parameters of a local dynamic impulse and to determine hazardous zones in the damaged structural system. The study employs direct nonlinear dynamic analysis, parametric modelling of five loading scenarios, and reduction of material properties in damaged zones. The consequences of the impulse are assessed by means of an integral structural damage index, a residual load-bearing capacity coefficient, a structural survivability index, and an operational reliability index. The results show a nonlinear increase in damage and an accelerated decrease in post-accident performance as the intensity of the local impulse grows. The most hazardous zones are concentrated at the lower storeys near the impulse application area and along the vertical chain of elements above the damaged region. The scientific novelty of the work lies in combining local impulse parameters with integral indicators of post-accident performance and a spatial hazard map. The practical value of the study consists in the possibility of using the obtained results to plan access routes, identify locations for temporary strengthening, and substantiate safe search and rescue tactics.