Dynamic seismic analysis of nuclear power plant buildings and bearing stratum

Various approaches are used for simulating seismic loading and collaboration of a structure and a bearing stratum when carrying out dynamic seismic analysis in specialized software. In the present work, the kinematic parameters of various structures and bearing stratum were calculated using SCAD and STAR_T software. Seismic performance of a reference tower type supporting frame was calculated for 7 grade earthquake. As a result, the floor accelerograms were calculated, and the floor response spectra were built. The calculation results obtained by various methods and structure models were analyzed and compared.

Crack resistance of masonry walls

Computer models used in the design calculation of masonry buildings sometimes fail to correctly take into account the stress-strain state of walls and assess the likelihood of cracks caused by the deformation differences of interacting walls.Following the construction of a building, cracks can develop at wall intersections for several years. However, their repair is mostly ineffective until the total damping of masonry creep deformation.Drawing on the analysis of conducted research and field data, the authors give recommendations on ensuring the crack resistance of internal masonry walls.

Ethics and science.The responsibility of the scientist

The article discusses the relationship between science and morality, the history of this relationship, and the reasons for a recent surge of interest in this issue. An attempt is made to identify internal and external mechanisms that regulate morality. The authors reason that among the most important of them are conscience, responsibility, and public opinion. The paper specifically addresses the problem of the responsibility of science, the structure of responsible actions, as well as new social relations emerging in the modern world.

Seismic resistance of frame-cladding buildings with a cold-formed galvanized steel profile framing

Building structural systems with light gauge steel framing technology are steadily gaining popularity due to their huge advantages over traditional technical solutions. As a result of the competitiveness inherent in LGSF technology, its application is gradually increasing in the manufacture of both bearing and nonbearing structures. At the same time, the actual absence of national standards for seismic design requires the development of programs and the implementation of research and development work to study the behavior of LGSF buildings in the conditions of seismic impact. The article touches upon the main problems of antiseismic construction of LGSF buildings and presents the results of domestic and foreign research.

Domestic and international best practice in research and testing glass for load-bearing structures of buildings

The present work provides an overview and analysis of scientific, technical, regulatory, and methodical Russian and foreign literature regarding using glass as a material for load-bearing structures of buildings. In the absence of design standards, an experimental study of usually one or two samples is necessary each time glass structure is used; however, this is insufficient to determine the distinct pattern of material performance. Since jointing the glass structures has been rarely studied, the number of tests is minimal, thus preventing establishing the unambiguous material operation and its calculated physical and mechanical characteristics. The article considers and evaluates the test results of glass structures obtained by various methods. The particular values of ultimate stresses and deformation modulus lie in a wide range. The technology, manufacturing process, and starting materials have a significant influence on the characteristics of glass, including multilayer glass. This article stresses the need for developing regulatory technical and methodical documents, the design and testing standards for glass structures and their jointing. It is necessary to classify load-bearing glass structures by various criteria.

Seismic design of NPP structures taking into account foundation slab compliance

The present article proposes a mathematical method for factoring in the compliance of foundation slabs in NPP structures under dynamic loading. In many cases, such an approach allows the analysis results to be significantly improved, whereas sometimes it is simply a necessary part of the procedure, i.e., when structures having “detached” exterior walls are exposed to an air shock wave generated by an aircraft crash.The presented method applies soil springs and dampers as per ASCE 4-16, specially distributed along the foundation slab bottom of a building.The conclusion presents the results of calculating the integral characteristics of soil springs and dampers according to the realistic (saddle-shaped) law of their distribution along the foundation slab bottom of a typical building.

Strengthening of building structures of historical masonry buildings in Syria with carbon fiber reinforced polymer (CFRP) rods and stainless steel helical rods

The article presents the most innovative methods of strengthening and (or) seismic strengthening of masonry for use in historical buildings that are of architectural value, for example, in old mosques in Syria, which are architectural monuments. These methods are designed to protect such buildings, many of which are of architectural and cultural value and are on the UNESCO World Heritage List, from cracks of various sizes and directions and from the negative effects of earthquakes that can occur at any time. Carbon fiber reinforced polymer rods (CFRP) rods and stainless steel helical rods are considered. Two mosques in Syria are briefly described as examples of historical masonry buildings, which are architectural monuments and objects of cultural heritage. In the end conclusions are drawn.

Research and development support of the spacer system for the foundation pit constructed by the Moscow method

The article presents the results obtained during the research and development support for the construction of the foundation pit for a projected hotel near the Kursky railway station in Moscow using the truss spacer system fixed in the diaphragm wall. This construction technique, called the “Moscow method” ensures the gradual soil excavation between the pit walls along tiers reinforced by steel spacer trusses to be performed simultaneously with installation of floor slabs. The developed and approved at TsNIISK named after V.A. Kucherenko method for determining stresses (deformations) in elements of metal structures using mechanical strain gauges with a removable indicator was applied to monitor the construction of a unique structure. During the monitoring, emergency situations, requiring extra measures for eliminating the identified unacceptable stresses in the structures, were identified. The provided example demonstrates the research and development support to a prerequisite for the construction of unique buildings and structures.

Accounting for horizontal torsional vibrations of foundations when calculating seismic load

The article presents a method for calculating in-plane vibrations of building structures under seismic load taking into account the possibility of foundation displacement, which is similar to horizontal torsional vibrations when calculating earthquake forces. The method is illustrated by the structural design of a seven-storey tower-like building with a massive foundation. We develop transfer functions for a massive rigid body, which are subsequently used for calculating the response of the foundation subject to base shears and moments applied to the outer plane of the foundation under seismic forces. The structural calculations conducted for ductile structures with the first frequency of ~2.4 Hz and for more rigid structures with the first frequency of 7.1 Hz showed that, depending on the building stiffness, reduced seismic forces increase by 1.5–2 times. According to the results obtained, when designing structures in areas of high seismic hazard, account should be taken of possible foundation flexibility effects depending on different types of soil and structural solutions of particular buildings.

Experimental studies of the operation of a frameless building made of thin-gauge structural sections

Light metal structures (LMS) are widely spread in domestic construction industry. A promising direction for the development of LMS includes prefabricated shell structures made of thin-gauge structural sections. The scope and operating conditions of such structures are quite extensive. In this regard, the development of a competent engineering methodology for calculating buildings using thin-gauge structural sections is required. The present paper describes a method for a full-scale testing of a shell building fragment and provides the results of forces and deformations calculated using the experimental model. In addition, an approach to modeling and dimensioning of finite elements for the profiles under consideration is described. The comparative analysis of numerical data and experimental results is performed. The results of the study can be used both for developing recommendations and engineering methods for calculating similar shell buildings and for determining the actual operational scheme for units and elements of the considered structure.