1.029
2712-8172
Magazine of Civil Engineering
5
31
2012
1-86
RAR
RUS
6-11
Stepanov
Vitaliy
Peter the Great Saint Petersburg Polytechnic University
vital60rus@mail.ru
Polytechnicheskay, 29
The method of corrosion crack opening evaluation for the reinforced concrete structures technical state assessment
The problem of the reinforced concrete structures technical state assessment assumes the improvement of techniques of their nondestructive control. Therefore, the technique based on criterion of integral values of the crack opening width is proposed. This criterion can serve as independent parameter of corrosion damage. Average value of crack width allows estimating thickness of corrosion products for determination residual bond between concrete and reinforcement. The comparative analysis with a standard technique of measurement is carried out. Shortcomings of maximum crack width as a parameter of serviceability are shown. The integrated technique does possible correction, taking into account nonlinearity of a crack, size of concrete layer, excludes manifestation of the methodical and subjective errors peculiar to a standard technique of measurement.
10.5862/MCE.31.1
corrosion
crack measuring
resource of structures
https://engstroy.spbstu.ru/article/2012.31.1/
01.pdf
RAR
RUS
12-22
Porivaev
Ilya
Ufa State Petroleum Technological University
iporivaev@gmail.com
Safiullin
Marat
Ufa State Petroleum Technological University
safiullinmarat@list.ru
Semenov
Alexander
Ufa State Petroleum Technological University
asfugntu@yandex.ru
1, Kosmonavtov St., Ufa, Russia
Research of wind and snow cover loads on the roofs of the vertical cylindrical tanks
The widespread use of vertical cylindrical tanks puts the question of their sustainable design. Snow load brings the greatest contribution to the stress-strain state of the supporting structures of vertical tanks spherical domed coatings in the IV-VIII snowy areas of Russia. New geometrical forms of the tank coatings with volume 20 000 m3 were developed. The results of aerodynamic research of proposed coatings model were presented.. The coefficients of the external pressure on the surface of the walls and coating of the tank were determined. Qualitative and quantitative picture of the snowy mass under the influence of the wind were also determined. The obtained results can be used to develop effective design solutions for domed coatings of the oil tanks.
10.5862/MCE.31.2
vertical cylindrical tank
domed coating
aerodynamic research
symmetrical snow load
asymmetrical snow load
https://engstroy.spbstu.ru/article/2012.31.2/
02.pdf
RAR
RUS
23-29
Melkumyan
Mikael
“Center of New Construction Technologies” of “Armproject” OJSC
mmelkumi@yahoo.com
Investigation of the effectiveness of single-mass and two-mass dynamic oscillation dampers on the model of frame building under the vibration testing
The given work to some extent meets the shortage of experimental investigations directed to the study of the behavior of buildings with dynamic oscillation dampers. Investigations were carried out by means of vibration testing on a large-scale model of a 9-story frame building. The purpose was revealing the effectiveness and damping properties of two-mass damper and comparing them with the effectiveness of single-mass damper. Before construction of such a damper in a form of an additional tenth floor, the dynamic characteristics of the model (periods and damping factors) were determined and their values are given in the paper. It was revealed that the maximum amplitude of oscillations on the top level of model (the slab of the 9th floor) with the main damper is almost 3 times less than the amplitude of oscillations on the top level of the model without damper. The amplitude of oscillations of the main damper was about 3-4 times bigger than the amplitude of oscillations on the top level of model. A damping factor of the main damper determined by the record of free oscillations was equal to ξ=0.7%. Then the damper was transformed from the single-mass to the two-mass damper by suspending the second mass to the slab of the main damper The obtained results show the high effectiveness of the two-mass damper as its damping degree reaches to about 4.4, that is 46.7% bigger than that of onemass damper. If before suspending the second mass to the single-mass damper its maximal amplitude was about 3.5cm, then after it the amplitude became equal to 1.4cm. The experimental investigations confirm the quite high effectiveness of the dynamic oscillation dampers and incontrovertible expediency of their application for increasing of earthquake resistance of buildings and structures.
10.5862/MCE.31.3
dynamic oscillation damper
seismic actions
harmonic oscillations
building model
vibration tests
damper tuning
damper effectiveness
https://engstroy.spbstu.ru/article/2012.31.3/
03.pdf
RAR
RUS
30-37
57204916380
0000-0002-6877-8420
Kozinetc
Galina
Peter the Great Saint Petersburg Polytechnic University
galina4410@yandex.ru
Polytechnicheskay, 29
Reliability validation of hydropower units of high-head developments
Throughout the development of the hydropower special attention was paid to the formation of a theoretical framework and methods of parameters and operating modes of powerhouses study. Under current design standards mathematical modeling of powerhouse is performed in two-dimensional for the axisymmetric problem. Up to now this method of simulation in Russia is the determining, although it has long lagged behind the capabilities of modern universal software of finite element analysis. The article presents analysis of the mathematical modeling methods for powerhouses of high-head hydroelectric power plants. Statement of the problem of three-dimensional modeling of the object – powerhouse is given. The procedure for multilayer three-dimensional modeling of water-conveyance conduits is presented. Outlined are the advantages of detailed numerical models of powerhouses in the context of their reliability verification.
10.5862/MCE.31.4
hydropower unit
three-dimensional mathematical model
finite-element analysis
multilayer model
steel casing
principal reinforcement
reliability
https://engstroy.spbstu.ru/article/2012.31.4/
04.pdf
RAR
RUS
38-42
H-9967-2013
16412815600
0000-0002-8588-3871
Kirsanov
Mikhail
National Research University "Moscow Power Engineering Institute"
mpei2004@yandex.ru
14, Krasnokazarmennaya, 111250 Moscow, Russia
Inductive analysis of the effect of error mounting on the stiffness and strength of a plane truss
For the trusses that are part of structures, the existing exact solutions does not contain an important variable parameter - number of panels or bars - and are written for a specific number that significantly reduces the value of them. Some well-known analytical solutions, which are valid for an arbitrary number of cores, usually greatly simplify the model of truss, roughly estimating the grid work, and are, in fact, approximate. With the advent of computer algebra systems we created the opportunity based on inductive method not only to find the exact solutions for any number of panels, but also to use them to evaluate more subtle phenomenon. In the article the impact of inaccurate mounting plane truss settlement through the maximum and minimum forces in the bars is estimated. We present an analytical solution under the assumption that the deviations of the provisions of the host truss are small. Several examples with the model farm scheme shows the potential of the analytical investigation of the stress state of the construction. The obtained solution depends parametrically on the number of panels and dimensions of truss. Inductive method with the support of computer mathematics Maple is used.
10.5862/MCE.31.5
truss
induction
error in installation
deterioration of hinges
deflection
Maple
https://engstroy.spbstu.ru/article/2012.31.5/
05.pdf
RAR
RUS
43-59
Zhgutov
Vladimir
"Kitezh" LLC Architecture and Construction Company
abc.kitezh@gmail.com
St. Petersburg, Russia
Geometrically nonlinear creeping mathematic models of shells with variable thickness
Calculations of strength, stability and vibration of shell structures play an important role in the design of modern devices machines and structures. However, the behavior of thin-walled structures of variable thickness during which geometric nonlinearity, lateral shifts, viscoelasticity (creep) of the material, the variability of the profile take place and thermal deformation starts up is not studied enough. In this paper the mathematical deformation models of variable thickness shells (smoothly variable and ribbed shells), experiencing either mechanical load or permanent temperature field and taking into account the geometrical nonlinearity, creeping and transverse shear, were developed. The refined geometrical proportions for geometrically nonlinear and steadiness problems are given.
10.5862/MCE.31.6
smoothly variable shells
ribbed shells
thermoelasticity
geometrical nonlinearity
creeping
transverse shear
https://engstroy.spbstu.ru/article/2012.31.6/
06.pdf
RAR
RUS
60-64
Denisov
Grigoriy
Peter the Great Saint Petersburg Polytechnic University
oxoxox@mail.ru
Polytechnicheskay, 29
On the vibrations localization in building structures
The article considers the local vibrations of elements of building structures. It is shown that under certain conditions, external influences cause vibrations of only some structural elements, but the whole structure stay in quiescence condition. The classification of local vibrations by the frequency characteristic is proposed. The limitation of spectrum of mechanical vibrations for buildings with structural damping due to the presence of dry friction forces is shown.
10.5862/MCE.31.7
vibrations localization
building structures
natural frequencies
damping
https://engstroy.spbstu.ru/article/2012.31.7/
07.pdf
RAR
RUS
65-71
56091980300
0000-0003-3850-424X
Lalin
Vladimir
Peter the Great St. Petersburg Polytechnic University
vllalin@yandex.ru
29 Politechnicheskaya St., St. Petersburg, 195251, Russia
Zdanchuk
Elizaveta
Peter the Great Saint Petersburg Polytechnic University
zelizaveta@yandex.ru
Polytechnicheskay, 29
A model of continuous granular medium. Waves in the reduced Cosserat continuum
In the description of vibrational properties of deformable bodies, it is usually assumed that the size of the oscillating particles is negligible in comparison with the average distance between them, so to describe the kinematics of such media only the displacement vector is used. In the majority of work is considered that when the independent rotational degrees of freedom are taken into account it become necessary to introduce the couple stress. Such models of continuous media are well known, for example, moment theory of elasticity or Cosserat media. A distinctive feature of the reduced Cosserat medium is that the stress tensor is asymmetric, and in static problems, this tensor becomes symmetric. Thus, in statics the reduced Cosserat media is indistinguishable from the the classical continuum in which the rotational degrees of freedom are not independent, as they are expressed in terms of displacement and the stress tensor is symmetric. In this paper we investigate the wave motion of a three-dimensional, isotropic, elastic reduced Cosserat medium, the characteristic velocities of wave propagation are finding, we also construct and analyze the dispersion curve for the dynamic equations.
10.5862/MCE.31.8
reduced Cosserat continuum
additional elastic constant
analytical solution
volume waves
dispersion
band gap
https://engstroy.spbstu.ru/article/2012.31.8/
08.pdf