ESTIMATION OF VARIABILITY OF STEPS OF ARMATURE IN A MONOLITHIC REINFORCED CONCRETE COVER OF A TOWER INDUSTRIAL CONSTRUCTION

Abstract

The work considers one of the possible reasons for reducing the operational reliability of monolithic thin-walled load-bearing reinforced concrete structures of existing industrial structures in relation to their design solution. As this reason is considered the variability of distances between axes of cores of working inspectedarmature of such designs is quite common.Comparison of design solutions with the qualityof construction and installation work makes it possible to identify the influence of unaccounted factors in the design of monolithic thin-walled reinforced concrete structures, which reduce their serviceability due to variability of concrete strength characteristics and actual longitudinal and transverse reinforcement due to variability of workingsteps. While processing the results of the survey ofmonolithic reinforced concrete thin-walled structures, which perceive the efforts of different levels,the question arises: which step of the working reinforcement, from a large number of actually measured steps, to choose in verified calculations –average or maximum, with extras.In the current norms, an indicator as the averagevalue of concrete strength for the calculation ofreinforced concrete monolithic slab structures doesnot appear, but is used as a statistically reasonablevalue of concrete strength, which takes into account its normalized variability with 95% security.Regulatory documents statistically estimates thevariability of reinforcement strength. At the sametime, they do not take into account the variabilityof the actual reinforcement of monolithic reinforced concrete structures, which is the subject forreconstruction of additional loads, but they aremade without observing the design distances between the reinforcement in these structures.When performing verified calculations of suchstructures for different design situations, to develop working designs for overhaul, reinforcement,reconstruction or dismantling, it is necessary todetermine which actual step of the working reinforcement should be taken with other defined design parameters of the structure.The authors instrumentally investigated and statistically analyzed the data of reinforcement of themonolithic reinforced concrete shell of the towerstructure, which made it possible to reasonablyaccept the values of the reinforcement steps in thetest calculations.