#### International Conference on Russian-Polish-Slovak Seminar Theoretical Foundation of Civil Engineering

##### Conference Information
Name: International Conference on Russian-Polish-Slovak Seminar Theoretical Foundation of Civil Engineering
Acronym: RSP
Location: Moscow, Russia
Date: 13 September 2021 - 18 September 2021

#### Latest articles from this conference

Published: 15 September 2021
Lecture Notes in Civil Engineering pp 364-373; https://doi.org/10.1007/978-3-030-86001-1_43

Abstract:
From a practical point of view, the most important feature of parametric vibration systems is the phenomenon of so-called parametric resonance. Parametric resonance occurs when a point specified in a parameter space of a differential equation system describing parametric vibrations is inside one of the instability areas of that equation. There are vibrations with exponentially increasing amplitude. According to linear vibration theory, this increase is unlimited, and therefore the only possible variant of eliminating this, generally negative, phenomenon is to change the parameters of the system to be outside the area of instability. According to Floquet's theory, the stability or instability of the parametric system is determined by the absolute values of the system multipliers, which are complex eigenvalues of monodromy matrix (Floquet transient matrix). If the module of the largest multiplier is less than unity – the system is stable, if it is greater than unity – the system is unstable. The work presented a method of automatic stabilization of resonant parametric vibrations. A procedure based on the concept of directional derivative was used. The idea is that, of all possible options for changing the value of the design parameters of the system, the system should be automatically selected as it will ensure that the modular value of the largest multiplier decreases as soon as possible. The method also uses algorithms of first and second order sensitivity analysis of continuous and discontinuous parametric periodic systems presented in the previous two years at the RSP Seminar in two works by Wójcicki [1, 2].
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 272-279; https://doi.org/10.1007/978-3-030-86001-1_32

Abstract:
Through a calculation model from the theory of limiting equivalence, from a corresponding system of equations for a two-dimensional problem set, the equivalence of limiting stress state of granular soil is determined to within a triaxial uniform compression equivalent to the coherence. The authors note the possible use of the result for the reduction of restrictions substantiated by the soil coherence (the routine studies do not assume any change in the soil coherence and in its own weight in accordance with the simulation conditions in the process of the experiment, hence the realization of these conditions with the change in the geometric scale similarity factor cannot be guaranteed for any choice of the force similarity factor. To illustrate the suggested method, based on the equivalence of soils in limiting stress state, the authors consider an example of determination of the active pressure onto the embankment wall caused by the own weight of the coherent soil.
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 53-62; https://doi.org/10.1007/978-3-030-86001-1_7

Abstract:
This paper presents results of a research on the effect of a high temperature, resulting from the storage technology, on the utilization level of stresses in selected individual structural components of a cylindrical, above-ground steel tank with a vertical axis and a fixed roof. Computational simulations were performed for the geometry of an existing facility that had failed during the service life. The analyses conducted resulted in specifying members, in the case of which taking into account thermal effects in the dimensioning process is desirable, undesirable or negligible from the point of view of operational safety.
, Dominika Vandličková
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 98-107; https://doi.org/10.1007/978-3-030-86001-1_12

Abstract:
In modern buildings are also currently used the wooden-based construction systems. A wide range of uses the timber constructions in apartment buildings is a vision of the countries of the EU. The use of timber and the other recyclable materials in apartment buildings creates the precondition for the implementation, operation and disposal of environmental impacts of the EU 2020 Strategy. In the long term is important to transform the construction of buildings to a sustainable standard. Currently, the fire height of timber apartment buildings in majority of EU countries is limited to 5 storeys. This paper deals with the influence of the ventilation parameter in the time and the intensity of the gas temperature during a fire in a model of an apartment building with a timber supporting structure. FDS (Fire Dynamics Simulator – PyroSim software) is used for dynamic simulations of fire in the model apartment.
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 433-439; https://doi.org/10.1007/978-3-030-86001-1_50

Abstract:
There are a number of tasks that require the creation of executive micro - or nanomechanical devices that allow you to convert one type of mechanical movement (for example, displacement) into another (for example, into oscillatory). Such devices that convert the energy of the input signal (electrical, optical, mechanical, etc.) into an output signal (for example, in controlled motion) are called actuators. Work on the creation of actors is underway in the UK, USA, Japan and a number of other countries. There are prototypes of actuators, but the problem of their autonomy has not yet been solved. In order for the actuator to become a real device suitable for practical use, it is necessary to solve a number of fundamental issues (to develop microminiature energy sources for their drive; to determine the methods and modes of activation of actuators that generate vibrations). Existing experimental and theoretical research in the field of self-oscillation of polymers allows us to hope for a solution to these problems in a simpler way. The studies performed below show that in accordance with the proposed rules for the selection of polymers for actuator drive polymethyl styrene and polycarbonate can be used as polymer systems in which self-oscillations will be excited in the frequency range of 200–250 Hz. The stretching rates at which the self-oscillations of the above polymers begin to be excited have been determined. The heat generated in this case can be used to maintain self-oscillations for a long time. The proposed approach can be considered as an alternative to mechanochemical actuators using methanol as a fuel. The ways of increasing their operating time and thermal effects when self-oscillations are excited in the frequency range of 200–250 Hz are considered. The glass transition temperatures Tg are calculated using the equation $T_{g} = \frac{{\left( {\sum\limits_{i} {\Delta V_{i} } } \right)_{p} }}{{\sum\limits_{i} {a_{i} \Delta V_{i} + \sum\limits_{j} {b_{j} } } }},$ where $\left( {\sum\limits_{i} {\Delta V_{i} } } \right)_{p}$ is the van der Waals volume of the repeating unit of the polymer; ai is a set of atomic constants characterizing the energy of a weak dispersive interaction as the average contribution of each atom to this interaction; bj is a set of constants characterizing the energy of a strong specific intermolecular interaction, such as dipole-dipole interactions and hydrogen bonds.
T. Bobyleva, A. Shamaev
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 20-26; https://doi.org/10.1007/978-3-030-86001-1_3

Abstract:
The paper presents analytical estimates of the proximity of solutions to boundary value problems for elastic-creeping layered composite materials, which are widely used in construction, and must withstand loads for a long time, and the corresponding averaged model for such a material. The estimates show the possibility of using the averaged model over a long time interval for the problem of loading by a constantly acting force action. Previously, this statement was substantiated by numerical experiments comparing the solutions of boundary value problems for the effective (averaged) model and direct numerical calculation using the original model for a highly inhomogeneous layered material. Analytical estimates are based on previously obtained estimates of the proximity of solutions to stationary problems of elasticity theory. The problem under consideration is reduced to such problems using the Laplace transform in time. Next, we analyze analytically the dependence of the estimates for stationary problems with a complex parameter of the Laplace transform on this complex parameter, and the reverse transition to the original variables (time and spatial coordinate) is performed. The method used in this work for estimating the proximity of solutions for the averaged and original boundary value problems can also be used in the study of dynamic problems of viscoelasticity. It should also be noted that for the one-dimensional model considered in this work, an interesting property has been established: if the constitutive relations for various phases are written as dependences of deformations on stresses, then the coefficients for the same form of writing the constitutive relation of the averaged model are obtained as simple weighted averages of similar coefficients for individual phases.
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 397-406; https://doi.org/10.1007/978-3-030-86001-1_46

Abstract:
One of the most important issue in multicriteria assessment is finding proper way of criteria weights estimation. It is especially problematic in assessment of newly introduced building materials, when almost none historic data is available. In this paper various methods of weights estimation are compared in valuation of various HLCs (Hemp-lime composites), commonly referred to as hempcrete. New method based on standard deviation of ratings in each criterion is proposed and compared with traditional, well-known algorithms such as Simos method, both variants of calculation proposed by Hokkanen and Salminen and REMBRANDT system.
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 178-186; https://doi.org/10.1007/978-3-030-86001-1_21

Abstract:
This paper shows an example relationship between CPTU cone resistance and oedometric modulus determined in laboratory tests. The coefficient $\alpha$ for weak soils is proposed on the basis of local experience by comparing the results of laboratory incremental loading oedometer and in-situ cone penetrometer (CPTU) tests. Laboratory tests served as a reference, while the interpretation of CPTU results was based on averaging the values of resistance on the cone qc for a given layer. Moreover, the authors showed how large the discrepancies in the obtained value may arise during the interpretation, only due to the selection of the coefficient $\alpha$. As cost-effective designing of the reinforcement of the soil nowadays is a difficult challenge the accurate determination of the coefficient $\alpha$ seems to be an essential part of geotechnical surveys.
Oleg Mkrtychev, Mikhail Andreev
Published: 15 September 2021
Lecture Notes in Civil Engineering pp 300-307; https://doi.org/10.1007/978-3-030-86001-1_35

Abstract:
The application of a simplified approach with the introduction of K1 to take into account the nonlinear behaviour of buildings and structures of some structural layouts when designing buildings and structures in seismically hazardous areas can result in a lack of seismic resistance. The use of nonlinear dynamic methods that allow the combined performance of reinforcement and concrete using finite solid elements to be explicitly considered can provide for more reliable results. The work evaluates the value of the allowable damage accounting factor K1 and assesses the actual level of seismic resistance of a 5-storey reinforced concrete cross-wall building given a seismic impact with an intensity of 9 points on the MSK-64 scale. For the building under consideration, a bearing capacity safety factor of Ksaf = 0.9 was obtained. The results of nonlinear dynamic analysis show that for a given building, low-frequency influences make a greater energy contribution to the system response than high-frequency ones. The values of the coefficient given in SP 14.13330.2018 ‘Seismic building design code’ to consider allowable damage K1 for buildings and structures of the corresponding structural layouts should be clarified, including using nonlinear dynamic methods. The results obtained in this work should be taken into account when calculating and designing multi-storey cross-wall buildings in earthquake-prone areas.