#4 2021
#4 2021

#4 2021

DOI: 10.37153/2618-9283-2021-4

№4 2021

Content

Clarification of the coefficient of responsibility K0 when calculating earthquake resistance for individual structural elements (columns) of multi-storey monolithic reinforced concrete frame buildings (in the order of discussion)

Authors:    Trekin N.N.    Kodysh E.N.    Shchedrin Oleg S.   
Rubric:     Theoretical and experimental studies   

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The analysis of the regulatory documents of the Russian Federation in terms of the requirements for accounting for the responsibility of buildings and structures when calculating for seismic impacts is given. For discussion, an approach is proposed to the differentiated assignment of the responsibility coefficient Kо for individual structural elements (columns) of a multi-storey monolithic reinforced concrete frame building when determining calculated seismic loads. Based on the results of calculations for an emergency settlement situation associated with the expected initial local destruction of the column, taking into account its different location in the plan and height for the columns, the values of the coefficients of significance of the location in the plan and the location in height are determined, taking into account the analysis of the calculated volumes of destruction, and are further used to clarify the values of the coefficients of responsibility Kо.


Application of augmented reality methods in construction

Authors:    Raziapov Ruslan V.   
Rubric:     Theoretical and experimental studies   

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The application of virtual augmented reality (AR) in the construction industry based on the use of information modeling technologies (BIM) has great prospects. An augmented reality space with a presence effect can facilitate better interaction between customers and specialists in various technical issues related to the implementation of the construction project. Combined with the concept of building information modeling, AR technologies can improve the general understanding of the construction process. Using the newest augmented reality technologies allows you to work out both the entire project and its individual details as accurately as possible. Object visualization in the real world can be improved by combining AR as well as BIM technologies, since the interactive capabilities provided by AR software and access to BIM information data allow you to more intuitively solve the tasks of maintenance and construction management. This article analyzes the current state of augmented reality technologies in construction, identifies the problems and prospects of using these innovative technologies in the construction sector, describes the methods of using the latest technologies under study in the construction sector, and also presents indicators affecting decision-making using augmented reality technologies. The article considers the possibility of reducing the implementation time of certain stages of investment and construction activities taking into account the introduction of augmented reality, provides examples of construction companies from different countries developing software and development companies using augmented reality technologies for marketing purposes, and concludes that augmented reality is promising in construction.


The influence of the shear connectors ductility on the seismic resistance of composite steel-concrete floors

Authors:    Tonkikh G.P.    Chesnokov D.A.   
Rubric:     Theoretical and experimental studies   

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According to the existing practice of composite structure design, shear connectors, which provide an interaction of supporting steel beams and reinforced concrete slabs, can be considered as ductile or non-ductile. Taking into account the ductility of connectors allows designer to create an optimal structure from an economic point of view and increase its earthquake resistance. Within the framework of this study, the results of push-testing composite specimen conducted by the authors earlier are considered. The powder-actuated shear connectors had been used for providing interaction between the steel and reinforced concrete parts. In conclusion, the assessment of the ductility and expediency of using powder-actuated shear connectors for earthquake-resistant construction is given.


On the possibility of redistribution of loads from the aggregate in silos as a result of seismic impacts

Authors:    Sharkov Vyacheslav P.   
Rubric:     Theoretical and experimental studies   

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Based on the calculation justification and analysis of experimental data, it is shown that in silos, as in hydraulic structures of cellular construction, as a result of seismic influences, in addition to inertial mass forces and alternating pressures of the filler on the walls, additional pressures associated with an increase in its hanging on the walls and the redistribution of loads that persist for a certain time may arise. The resulting pressures on the walls can be determined according to the author's formula and for a sand aggregate exceed static ones: 1.57 times – lateral, 1.2 times – vertical, associated with the development of friction forces The reason for the occurrence of load redistribution is the development of friction forces at the walls, which occurs as a result of aggregate precipitation during vibration compaction as a result of seismic influences. This phenomenon can be observed in silos, in which large values of dynamic coefficients arise during fluctuations. Calculations supported by experimental data show that under 9-point seismic impacts, the redistribution of loads with an increase in pressure to the above values can be observed along the entire height in silos with sand aggregate up to 25 m high with a diameter of 3m to 6 m, and in silos with a diameter of 8 m – in the upper part to a depth of 13 m. At 8-point seismic impacts, this phenomenon can occur in silos with small diameters of 3m and 4m with an increase in pressure in their upper part with a depth of 3m to 5m, and at 7-point – it covers only the upper part of structures with a depth of 1...1.5 m, that is, practically absent.


Probabilistic estimation of reliability and failure values for monolithic buildings based on the results of certification

Authors:    Vladimir A. Lapin    Yerkin S. Aldakhov    Serik D. Aldakhov    Alimzhan B.Ali    
Rubric:     Monitoring and certification of seismic constructions   

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In 2017-2018, the total certification of the housing stock of multi-apartment buildings in Almaty was carried out for the first time. According to the results of certification, a total of 8,171 buildings were entered into the database, of which 1,425 are multi-storey monolithic buildings of various storeys and structural types. It was also revealed that 1305 monolithic buildings are earthquake-resistant, 27 – non-earthquake-resistant and 93 are located in the zone of tectonic faults on the territory of the city. Therefore, it is useful to accept the pessimistic hypothesis that buildings located in the zone of tectonic faults will be destroyed. Under these conditions, quantitative estimates of the failure probability and reliability values for monolithic buildings were obtained for the first time. The high earthquake resistance of monolithic buildings has been confirmed. It is established that when taking into account the influence of tectonic faults, the probability of failure of a monolithic building increases by more than 4 times. The frequency of earthquakes is taken into account according to the current "Map of seismic zoning of the Republic of Kazakhstan". Methods of strengthening monolithic buildings should be individual and determined by the results of experimental studies.