Reliability of steel frameworks of industrial buildings = Надійність сталевих рам виробничих будівель

Abstract

The work is dedicated to the reliability assessment of one-storey industrial buildings with overhead travelling cranes. Problems of reliability assessment of such buildings are compared with the complex character of external loads. The nature of this loads is complicated and depends on many spatial and space-temporal factors. Among all of the loads which influences on industrial buildings crane loads have the largest values. Often these loads define the architecture and spatial design of workshops, materials and weight supporting structures. The analytical probabilistic model of crane loads was established in the work. This model allows to obtain actual reliability parameters of buildings with overhead cranes. Travelling cranes with the capacity from 5 up to 50 tons with different types of drive modes and regimes of work were chosen for the calculations. The location of travelling cranes was considered in buildings with different columns spacing, different types of coverage and bracing structures that provide space work of frames. Consideration of the spatial nature of frameworks in calculations has permitted to detect the reserves of frameworks of industrial buildings and identify the influence of bracing elements on the reliability assessments. The calculation of spatial models of industrial buildings were done on the combinations of all influencing loads, including crane loads. Spatial design models of frames were formed out spatial blocks of buildings, which included all transverse frames or middle blocks with 7-10 frames. It was determined, that the structures, which mainly provide space behavior and which should be considered while forming design models is the covering of buildings, bracing elements on the lower boom of the roof truss, crane girders with braking force transferring girders and longitudinal working platforms. To identify the quantitative impact of bracing systems on the reliability of frameworks the bracing blocks were removing alternately until the transverse frame of the building was obtained. The parameters of the plane frame were compared with the parameters of the frames in the space blocks. Probabilistic calculations of the columns as the parts of frameworks models with bracing systems (crane girders with braking force transferring girders, bracing elements on the lower boom of the roof truss) showed high reliability of structures of typical industrial buildings, for which the probability of failure during 50 years is . The attaching other elements, such as bracing elements on the upper boom of the roof truss, purlins of coverage, horizontal beams of wall trelliswork, in design models showed a minor influence on the reliability of frameworks. The probability of failure reduces steeply if the bracing elements of the roof truss and braking force transferring girders were not taken into account in spatial models of the frameworks.

Робота присвячена оцінці надійності одноповерхових промислових будівель з мостовими кранами. Проблеми оцінки надійності таких будівель порівнюються із складним характером зовнішніх навантажень. Характер цих навантажень складний і залежить від багатьох просторових і просторово-часових чинників. Серед усіх навантажень, що впливають на промислові будівлі, кранові навантаження мають найбільші значення. Часто ці навантаження визначають архітектуру та просторовий дизайн майстерень, матеріалів та вагових опорних конструкцій. В роботі була встановлена ​​аналітична ймовірнісна модель кранових навантажень. Ця модель дозволяє отримати фактичні параметри надійності будівель з мостовими кранами.