Extending industrial objects’ life by introduction constructive measures

Abstract

An accumulation of defects caused by the action of the loads both man-made and external leads to a decrease in the carrying capacity of the carcass structure during operation of industrial buildings. Most notably this problem manifests itself in the buildings equipped with crane equipment. During operation the columns and crane girders obtain significant deformation, and this entails a reduction in structural stiffness characteristics. At the same time a load factor is enhanced when using heavier equipment. Therefore, the main purpose of this study is to identify the opportunities to ensure the reliability required for an industrial building equipped with overhead cranes. The study has developed a complex of calculation methods, the main task of which is to estimate the residual resource of a specific period of technical system operation, taking into account the random nature of a whole set of disturbances. The analysis of the results obtained by the consistent implementation of these techniques allows tracking the dynamics of changes in the stress-strain state of load-bearing structures of industrial objects in operation.In order to solve the problem of providing rigidity frames and improve the reliability of their safe operation the authors propose constructive measures to slow the rate recorded in the calculation of the bearing capacity loss of the system. For this aim we suggest setting the end face transverse stiffening diaphragms, increasing the rigidity of the column above the crane, arranging some connecting rods in the temperature seam, located in the levels of coating and under crane beams. These measures should be used together, which allows achieving a significant effect in providing transverse rigidity. The coating disk with a sufficiently high horizontal rigidity is able to transfer a portion of the load acting on the transverse frames on transverse end faces of the diaphragm. The binder rods prevent relative lateral displacement of the temperature blocks relative to each other, thereby they put the entire frame under the action of horizontal crane loads into operation. Increasing the stiffness of the column above the crane allows transferring a significant part of the effort to the coating when the bridge crane has close proximity to the coating.The proposed constructions are easy to manufacture and do not require the device holes, which weaken the structure. They can be made not only while erecting the buildings, but also in the already constructed ones by increasing the carrying capacity of the overhead cranes. In this paper we evaluate the effectiveness of the proposed measures to improve the structural rigidity of frameworks on the example of several industrial buildings. The comparative analysis of the results obtained before and after the introduction of affirmative action has shown that their arrangement reduces the horizontal displacements of the frame, in the level of crane girders, and the level of coating, with a larger effect observed in the buildings with heavy-duty overhead cranes. This reduction of displacement involves the growth of bending moments values in above the crane column part and the reduction of the magnitude moments in the under crane part. At the great height under the crane portion of the column in most buildings these changes can save generally significant amounts of steel for the framework.Thus, the proposed technical solutions are aimed not only at extending the safe operation of industrial buildings, but also have a positive effect in case of re-production associated with an increase in the lifting capacity of crane equipment, with little financial cost.