Safe operation, reliability and durability of capital facilities (hereinafter – CF) are becoming more and more topical. All phases except operation (including all types of maintenance and repairs) and demolition were covered by regulatory requirements, while operation as the longest phase in CF life and the final stage - demolition were not included into regulations until recently. There were industry specific codes for nonproduction and industrial buildings and facilities and documents derived from them, but they were inconsistent, lead time to repair differed even for similar structures and operation conditions and these discrepancies did not allow setting the specific frequency of repairs which resulted in neglected defects and damages shortening the life of buildings and structures or causing accidents. In 2015, the authors, in team with other experts, developed SP 255.1325800.2016 “Buildings and structures. Rules of operation. Key provisions” (hereinafter - SP 255), setting general requirements to operation of buildings and structures under regular conditions, but the diversity of buildings’ functions required the development of numerous codes of practice derived from SP 255 and some of them were drafted in 2016-2018. Codes of operation practice will (if elaborated) contribute to the reduction of operation and maintenance costs and ensure required safety of capital facilities.

В данной статье предлагается к рассмотрению методика оценки эксплуатационной безопасности зданий и их конструкций, устраняющая некоторые недостатки существу­ющих методик расчёта остаточного ресурса по физическому износу (повреждённости) строительных конструкций по результатам визуального обследования. Основу методики составляет зависимость допустимого срока безопасной эксплуатации от процента сниженной несущей способности. Предлагаемая методика состоит из двух этапов.   На первом этапе определяют допускаемые сроки экс­плуатации между обследованиями зданий в зависимости от категории технического состояния отдельных конструкций. В методике учтено, что разнообразные по типу дефекты, каждый из которых по своему размеру может характеризо­вать ограниченно-работоспособное состояние, могут оказать суммарное более негативное воздействие на конструкцию и в конкретный период времени ухудшить её техническое состояние, например, вызвать переход из ограниченно-ра­ботоспособного состояния в аварийное. Второй этап методики включает определение ориен­тировочных сроков до проведения капитального ремонта зданий. При назначении величин значимости конструкций был принят дифференцированный подход в зависимости от конструктивной системы здания, учитывающий тре­бование по обеспечению безотказной работы объекта строительства.

The construction of the radio tower engineer V. Shukhov. For almost one hundred years the structures and components of the radio tower are heavily corroded which resulted in local damage. The danger of accumulation and increase of local damage is that they lead to the collapse of the tower. In 2016 anti-damage support structure was made to exclude the sudden avalanche-like collapse of the structure of the radio tower engineer V. Shukhov (Fig. 1). But there is a risk of formation and distribution of local damage. The checking calculation of the Shukhov radio tower was performed to identify the impact of the anti-damage support structure, taking into account the local damage. The calculation was made at the software complex “Lira-CAD”. Normative loads, their application, reliability coefficients for loads and combination coefficients are adopted in accordance with Building Act 20.13330.2016 “Loads and impacts”. The compatibility of the Shukhov radio tower and the anti-damage support structure is provided by pre-tension in the suspensions units of the radio tower attached to the support structure consoles. The tension force was determined by the calculation based on the experimental results of 2015. The results of the combined geometrically nonlinear analysis of the Shukhov radio tower and the support structures showed the increased overall stability of the radio tower; the maximum movement of the unit stands and support rings was reduced by 20-30%, the maximum stands stress were reduced by 10-15% due to the load redistribution among the stands, but the maximum stress slightly exceed the allowed value. The complex of checking calculations of the Shukhov radio tower and the supporting structures showed that the existing anti-damage construction eliminates a sudden avalanche-like collapse of the structure. There is a risk of formation and distribution of local damage with the irreversible deformations of the stands and support rings of the radio tower with the increase of defects and damages of the structure of the radio tower which are still in a damage state. For a more uniform distribution of loads and increase the overall stability of the structure, it is necessary to increase the number of consoles of anti-damage support structure to 24 at each level of the support structure. Full-scale restoration works of the Shukhov radio tower structures are required to prevent the formation and distribution of local damages.

No abstract

The article deals with the operation problems of space lattice constructions (SLC) of the Kislovodsk-type, revealed as the results of a survey of more than ten structures within the period from 2000 to 2020. The main causes of accidents of the SLC system was revealed and presented. The disadvantages of production mounting of the Kislovodsk-type system with a hidden capital are considered; the recommendations for preventing the displacement of the SLC support connectors of the Kislovodsk-type system with a hidden capital are presented. As an example, the collapse causes of the Kislovodsk structure made with a hidden capital according to a rare scheme operated in Syktyvkar were analysed in the work. The results of numerical study of the load-bearing capacity of constructions made in CAD SCAD 21.1.1.1 were presented. The most common structural defect of this type – the elements overload of the SLC system is considered in this work. The calculation showed that the structural plate has a three times overload of 35% of the elements (compressive stability, strength). The overload is connected with the normative load increase of snow cover in 2003 and in 2016, and the weighting of the roof structure (twice as compared to the production solution) during its repair work. The load calculation was based on the survey of the SLC constructions. Based on analysis of constructions of this type, the authors give the recommendations on the list of works required for additional inclusion in the survey program of the technical condition of constructions.