INFLUENCE OF THE PROBABILISTIC METHOD TO SUMMARIZE LOADS ON THE RELIABILITY AND MATERIAL CONSUMPTION OF BUILDING STRUCTURES

Abstract

Introduction. Load rates are one of the main factors affecting the assessment of the reliability of building structures. All loads are probabilistic in nature, but short-term loads are the most representative in terms of this study since they have the most stochastic nature compared to other types of loads. According to regulatory documents, the short-term loads on a building should be summarized based on their base return period — 50 years. Due to variety of design situations, it is impossible to optimally standardize calculation methods for all types of buildings, therefore, the return period of 50 years is taken for all types of buildings regardless of their required useful life, which in some cases may lead to an excessive safety margin. Methods. To summarize loads on the structural schemes of buildings, two methods are used: deterministic, which is based only on data from regulatory documents, and probabilistic, which takes into account the probabilistic nature of the origin of loads. Reliability is assessed by the limit state method and Rzhanitsyn method. Results. In a number of cases, the use of the probabilistic method when summarizing loads makes it possible to reduce the stiffness properties of sections by equating the period of return of probabilistic loads to the required useful life of the building. Thus, reliability is guaranteed not for 50 years (as in the deterministic method) but for the useful life of a building, and, as a result, the reliability of building structures is not reduced during the entire set period of their operation. This method made it possible to reduce the total weight of the frame of an industrial building by 3 %, and that of a small-sized building — by 27 %, which indicates a more rational application of the proposed method to small-sized building schemes, since in large schemes the gains from the reduced material consumption in structures will be neutralized by the consequences of their failure and the cost of equipment inside the building.