75504 2712-8172 1 53 2015 1-116

RAR RUS 6-14 6602444316 LLC Research and Production Company “SCAD Soft” Perelmuter Anatoliy avp@scadsoft.com

Kiev, Ukraine

National Research Moscow State University of Civil Engineering Kabantsev Oleg ovk531@gmail.com

Moscow, Russia

Accounting for the elements stiffness change in the course of erection and operation The problem statement related to modification of structural design model, when stiffness parameters of the structural members undergo changes, was considered. Some data was outlined from the design practice concerning design cases that occur during erection and maintenance of buildings and structures, when stiffness parameters of some structural members undergo changes. A physical mechanism that controls changing of these parameters was described for some of the design cases. Likewise, attention was paid to the design cases when changing of stiffness parameters has no relation to changing of actual stress-and-strain state and when such change occurs. Appropriate analysis methods were described. 10.5862/MCE.53.1 modeling load-carrying structures stress-and-strain state design prediction calculation technique design model model of external constraints action model https://engstroy.spbstu.ru/article/2015.53.1/ 01.pdf

RAR RUS 15-23 Vologda State University Utkin Vladimir UtkinVoGTU@mail.ru

Vologda, Russia

Determination of residual load-bearing capacity of concrete beams at the operation stage by the strength reinforcement and concrete criterion An experimental theoretical method was considered for estimating the residual load-bearing capacity of an individual reinforced concrete beam at the operational stage according to the criteria of the working strength and durability of concrete reinforcement compressed zone of the beam. Integrated methods of beam testing and probabilistic methods of random variables definition were used. Ultimate load in the form of interval during the operational phase was accepted as the measure of carrying capacity, discussion is presented on the choice of its value obtained from the interval boundary that has been obtained. Transition from the experimentally obtained value of the ultimate load to the maximum operational load was studied. Examples of design models of beams with operational load and guidelines on how to determine their limit values were given. 10.5862/MCE.53.2 bearing capacity of reinforced concrete beam the strength of reinforcement concrete strength ultimate load the design scheme https://engstroy.spbstu.ru/article/2015.53.2/ 02.pdf

RAR RUS 24-31 Moscow State University of Civil Engineering Tusnin Alexandr valeksol@mail.ru

Moscow, Russia

Moscow State Civil Engineering University Prokic Milan prokic@mail.ru Experimental research of I-beams under bending and torsion actions The article presents the results of the theoretical and experimental research of I-beam behavior under combined bending and torsion. The analysis of numerical models was carried out, including calculations in which the physical and geometrical nonlinearity was taken into account. Based on the calculations, the parameters of experimental models and the value of the applied loads were determined. The samples were tested under the bending and torsion actions up to moment the element lost its bearing capacity completely. The experimental results were compared to the theoretical and numerical calculations. Correspondence between theoretical and experimental results was established (as a rule, the difference does not exceed 15%). The accuracy of the applied numerical methods for the analysis of beams under bending and torsion with due consideration of plastic deformation development was confirmed, which allows using them for developing engineering methods of beam calculating. 10.5862/MCE.53.3 I-beam warping torsion bending tests numerical calculations bearing capacity https://engstroy.spbstu.ru/article/2015.53.3/ 03.pdf

RAR RUS 32-38 H-9967-2013 16412815600 0000-0002-8588-3871 National Research University "Moscow Power Engineering Institute" Kirsanov Mikhail mpei2004@yandex.ru

14, Krasnokazarmennaya, 111250 Moscow, Russia

Deflection analysis of rectangular spatial coverage truss An elastic spatial statically determinate truss of regular type, simulating the rectangular in plan coverage was considered. In the plane of the base the truss has two axes of symmetry. Four support structures (spherical hinge, cylindrical hinge and two vertical rods) are located at its corners. An analytic solution was found for forces in the rods of the truss. Using the Maxwell-Mohr’s formula, the dependence of the deflection of the center was discovered in the truss under the influence of the concentrated force. There are five parameters of the problem in this formula: three linear dimensions, and the numbers of hinges on its lateral sides. To determine the desired patterns by means of the computer mathematics system Maple the recursion task by two parameters was solved. It was shown that dependence of the deflection on the number of panels and height of the truss detects a minimum, allowing optimizing the size of the structure. 10.5862/MCE.53.4 deformation method of induction space truss; coverage https://engstroy.spbstu.ru/article/2015.53.4/ 04.pdf

RAR RUS 39-55 56091980300 0000-0003-3850-424X Peter the Great St. Petersburg Polytechnic University Lalin Vladimir vllalin@yandex.ru

29 Politechnicheskaya St., St. Petersburg, 195251, Russia

Peter the Great Saint Petersburg Polytechnic University Beliaev Mikhail belyaev-m-o@yandex.ru

Polytechnicheskay, 29

Bending of geometrically nonlinear cantilever beam. Results obtained by Cosserat – Timoshenko and Kirchhoff’s rod theories The problem of verification of different program suites for structural analysis has recently become an important component of the construction science. One of the most extensively used benchmark problem is a classical geometrically nonlinear problem of deflection of the cantilever beam of linear elastic material, under the action of external vertical concentrated load at the free end. In fact, the solution for Kirchhoff’s rod is used as an analytical result. This rod is inextensible and Kirchhoff’s rod theory disregards flexibility of the rod in tension and shear. But in modern program suites Cosserat-Timoshenko rod is often used because Cosserat-Timoshenko rod theory is a geometrically exact theory. It considers not only bending strain but also shear and tensile strain. This means that it is necessary to get a model solution for Cosserat – Timoshenko rod, which can be used for verification of different software suites. This paper presents solutions of the geometrically nonlinear problem obtained by Cosserat – Timoshenko and Kirchhoff’s rod theory with comparison of those results. The findings can be used as a benchmark problem for verification of software suites. 10.5862/MCE.53.5 Cosserat – Timoshenko rod theory Kirchhoff’s rod theory geometrically nonlinear rods parameter differentiation method benchmark problem https://engstroy.spbstu.ru/article/2015.53.5/ 05.pdf

RAR RUS 56-69 Kyiv National University of Construction and Architecture Solovei N. Kyiv National University of Construction and Architecture Krivenko O. olakop@ukr.net Kyiv National University of Construction and Architecture Malygina O. oksalita@mail.ru Finite element models for the analysis of nonlinear deformation of shells stepwise-variable thickness with holes, channels and cavities The method of solving static problems of nonlinear deformation, buckling, and postbuckling behavior of thin elastic inhomogeneous shells is based on the geometrically nonlinear equations of the 3D thermoelasticity theory and use of the moment finite-element scheme. A unified model has been created based on the universal spatial finite element with additional variable parameters. The model considers the multilayer structure of a material and geometrical features of structural elements of an inhomogeneous shell: casing of varying thickness, ribs, cover plates, cavities, channels, holes and sharp bends of the mid-surface. In a number of the authors’ works the reliability of linear and nonlinear solutions for a wide class of inhomogeneous shells has been numerically justified by analyzing their convergence and comparing them with those obtained by other authors. This paper is devoted to the comparative analysis of finite-element models and results of calculation of thin elastic shells using the moment finite-element scheme, and LIRA and SCAD program complexes. The effect of different types of weakening on nonlinear deformation and buckling of shells was studied on the example of isotropic panels under uniform pressure. 10.5862/MCE.53.6 flexible shell moment finite-element scheme nonlinear deformation buckling; stepwise-varying thickness weakening https://engstroy.spbstu.ru/article/2015.53.6/ 06.pdf

RAR RUS 70-79 Volga State University of Technology Ivanov Oleg IvanovOG@volgatech.net Volga State University of Technology Shlychkov Sergey shlychkovsv@volgatech.net Сomputation of prismatic shells in elastic medium The paper presents a computation procedure of physically nonlinear prismatic shells with the sealed ends. It is known that plates reinforced by stiffening ribs and located in the elastic medium can be calculated in a similar way as uniform ones (without reinforcements). In this case the effect of edges on the stress-strained state of plate was calculated in the form of the elastic support by Winklerian model. Thus, contact with the elastic medium was simulated, the medium was assumed in the form of a single-layer base. Dependence between the intensities of stresses and strains was established as a cubic polynomial. Fundamental differential equations were derived on the basis of the energy method. Final equations were realized by the numerical method of Runge – Kutta. Computation of U-shaped shell was executed on the basis of the obtained equations. Evaluation of the influence of elastic medium and physical nonlinearity on the stress-strained state of lamellar system was represented. 10.5862/MCE.53.7 physical nonlinearity plate systems the elastic support https://engstroy.spbstu.ru/article/2015.53.7/ 07.pdf

RAR RUS 80-90 Institute of Mechanics and Seysmic Stability of Structures Usarov M. umakhamatali@mail.ru Buckling of orthotropic plates with bimoments The paper is dedicated to improvement of plate theory in order to take into account forces, moments and bimoments, generated by nonlinear law of displacement distribution in plate cross-sections. Integral correlations for defining forces, moments and bimoments were given. The developed bimoment plate theory is described with two independent two-dimensional systems with nine equations in each. On each edge of plate nine boundary conditions were set. The approach to building the bimoment theory is based on the Hook law, three-dimensional equations of elasticity and decomposition of displacements in Maclaurin series. As an example, the solution of the problem of thick orthotropic plate buckling under action of transverse harmonic sinusoidal load was described. Numerical results were obtained for displacement, force, moments, bimoments and stresses, accompanied by analysis. 10.5862/MCE.53.8 Hooke’s law orthotropy theory of elasticity 3D problem thick plate planar problem force moment bimoment bimoment theory https://engstroy.spbstu.ru/article/2015.53.8/ 08.pdf

RAR RUS 91-96 TEKTON Co. Ltd Shirunov G. guriyn@mail.ru Method of initial functions in model of compression linearly deformable layered foundation under normal local load The three-dimensional problem of the theory of elasticity related to isotropic layer compression by normal load, distributed on a limited area, is solved by the method of initial functions (MIF). The layer divided into separate sub layers with different elastic characteristics serves as a model of the multilayer foundation. A parallelepiped cut out from the infinite layer with dimensions much larger than those of the load area may be considered as an elastic half-space. A numerical-analytic solution was obtained by a specially designed program based on the symbolic computation system called Maple, in which the desired functions of the displacements are represented by a Fourier series. The problem of computational instability calculations inherent in MIF at high numbers of harmonics was solved by using representation of real numbers with sufficient length mantissa. The results were compared both with solutions of the classical theory of elasticity for elastic halfspace, stipulated in the guidelines for designing foundations, and with the finite element method solutions. 10.5862/MCE.53.9 theory of elasticity elastic layer elastic half-space method of initial functions numerical–analytical solution finite element method multilayer foundation https://engstroy.spbstu.ru/article/2015.53.9/ 09.pdf