1.029
2712-8172
Magazine of Civil Engineering
1
27
2012
1-133
RAR
RUS
4-13
Ulybin
Alexey
Peter the Great Saint Petersburg Polytechnic University, PRDI “Venchur”
ulybin@mail.ru
Polytechnicheskay, 29
Inspection methods of reinforcement parameters of concrete structures
One of the main objectives during the detailed examination of the supporting structures made from any construction materials is receiving data to perform calculations. For reinforced concrete structures the most difficult task is to determine the parameters of steel reinforcement, as it is always under a protective layer of concrete. The paper deals with the main problem of reinforcement parameters determination of concrete structures in the inspection. The basic well-known tracks of a solution to this problem are analyzed. The most reliable and accurate methods of reinforcement parameters determination are revealed. The magnitude of error of the magnetic inspection method in the determination of the diameter of reinforcement and the coverage is experimentally detected. The availability data of applying the method of hardness measuring for the reinforcement class determination is adduced.
10.5862/MCE.27.1
class of reinforcement
reinforcement parameters
reinforced concrete structure
non-destructive testing
an inspection of structures
https://engstroy.spbstu.ru/article/2012.27.1/
01.pdf
RAR
RUS
14-21
Zolotcov
Anatoliy
Ministry of Regional Development and Construction, Republic of Moldova
zolotcov@gmail.com
Vibration tests on fragments of monolithic building until destruction
The full-scale vibration testing of buildings plays an important role in the development of monolithic construction. This article describes the methodology and results of tests carried out in Chisinau. For full-scale tests two six-floor fragments of monolithic constructions in industrial solid tile formwork on foundation plates 9840x14600x400 mm in size were built. The purpose of the tests was to determine the influence of structural systems on technological joints, the specifics of the contour and field reinforcement, as well as the development of analytical method for calculating strength of monolithic walls of buildings taking into account the seismic effect. Both pieces were destroyed. The destruction reached the 4-th level. At this stage, the tests were stopped and the both fragments had been consolidated using polymeric compositions. This experiment allowed to specify the calculation models of the monolithic constructions and to test earlier developed analytical methodology, to calculate the seismic impact, to validate experimentally the effectiveness of the various systems of reinforced solid walls, to monitor changes in their dynamic characteristics in the process of plastic deformations and damages in constructions development. The results of the described vibration test of the monolithic parts in conjunction with stand static tests of monolithic walls were used in the formulation of construction standards for cast-in-place construction of the Republic of Moldova.
10.5862/MCE.27.2
monolithic housing construction
earthquake engineering
vibration machine
seismic effects
vibrodynamic buildings testing
the degree of structures damage
dynamic characteristics
an analytical technique
the walls reinforcing system
https://engstroy.spbstu.ru/article/2012.27.2/
02.pdf
RAR
RUS
22-30
Rumyantsev
Yevgeniy
Proektnoe upravlenie ShtriKH, LLC
jekarum@yandex.ru
Belugina
Ye.
Uralpromproekt, OJSC
Station Adler railway terminal structures modelling taking into account seismic base isolation
The article discusses methods of building frame constructions modeling by finite element method, taking into account seismic isolation systems. It presents data of the calculation in the two software systems. The calculation results are compared by analyzing of the individual elements stress-strain state. Recommendations about the calculation schemes and software systems selection are given on the base of results analyzing. The achieved results allow us to evaluate the effectiveness of seismic base isolation and can be used for wide application of such systems in building area.
10.5862/MCE.27.3
seismic base isolation
lead rubber bearings
finite element method
linear spectral theory
the method of direct time integration
synthesized acceleration
https://engstroy.spbstu.ru/article/2012.27.3/
03.pdf
RAR
RUS
31-36
Rutman
Yuriy
Saint-Petersburg State University of Architecture and Civil Engineering
605fractal@mail.ru
2-nd Krasnoarmeiskaya St. 4, 190005 St. Petersburg, Russia
Pendulum seismic isolation bearings. Design, analysis, experiment
In the present research a pendular type of seismoisolation system for protection construction from earthquake is considered. Seismic isolation is carried out on the basis of the following principles:
• the natural frequency of the "protected object - seismic isolation" should be significantly
lower than the main energy contained frequency (which leads to high frequencies filtering);
• damping in seismic isolation systems should be high enough to avoid resonance effects;
• in seismic isolation systems can be applied elements that limit the level of force that is passed to the protected object (a plastically deformable or friction elements).
A design of devices (component of seismoisolation systems) is shown in the article. The methods of seismoisolation systems analysis are described and the results are presented. The main results of dynamic tests of those devices are shown.
10.5862/MCE.27.4
seismic isolation
seismic isolation bearing
seismic devices
damping
seismic tests
dynamic analysis
https://engstroy.spbstu.ru/article/2012.27.4/
04.pdf
RAR
RUS
37-43
Kovaleva
Nadezhda
State Marine Technical University, Saint-Petersburg
balloun@yandex.ru
Rutman
Yuriy
Saint-Petersburg State University of Architecture and Civil Engineering
605fractal@mail.ru
2-nd Krasnoarmeiskaya St. 4, 190005 St. Petersburg, Russia
Estimation of efficiency of damping parameters in seismic insulation systems
In the design of seismic isolation systems, one of the key and most difficult issues is the damping optimal parameters choice. If the damping is negligible, it is possible (at a certain frequency of external influence) that quasi-resonant processes, which lead to the disappearance of seismic insulation effect, will emerge. If the damping forces are large, it entails a significant load increase on the protected object, which also reduces the effect of seismic insulation. Development technique of plastic dampers analytic dependence «force-displacement» executed as linear or nonlinear quarter circle cores is presented in the research. These dependences are applied to choose rational parameters of pendular type of seismic insulation system damping.
10.5862/MCE.27.5
damping
plastic dampers
force characteristic
dynamic analysis
seismic insulation
https://engstroy.spbstu.ru/article/2012.27.5/
05.pdf
RAR
RUS
44-52
Simbort
E.
Saint-Petersburg State University of Architecture and Civil Engineering
e-simbort@mail.ru
Selection procedure of seismic-load reduction factor K1 at a given level of ductility factor
At the present time for providing earthquake resistance of buildings and structures, the multilevel design approach is applied. According to this approach seismic loads corresponding to the level of the maximum design earthquake must be perceived by building through the plastic resource of structures, and at the same time the complete collapse of buildings or parts of it must be prevented. In the standards of foreign countries the work of the construction outside the elasticity limit is taken into account by the reduction factor. The load reduction factor selection consists in reducing the seismic loads, depending on the maximum (allowed) level of residual deformations in structures due to earthquakes. The maximum residual deformations are taken into account by ductility factor. In the present research a nonlinear system with single degree of freedom is used for analyzing the behavior of structures under elastoplastic deformation. The author obtained the relationship between plasticity factor and yield strength of structure characterized by the reduction factor K1. The statistical analysis of data was also carried out in order to estimate the values of the reduction factor K1. Such approaches have already been practiced, but such relations were obtained only for simple loadings. In this paper, these dependences were obtained for more complicated, earthquake loadings.
10.5862/MCE.27.6
seismic-resistant design
nonlinear single degree of freedom model
reduction factor К1
ductility factor
https://engstroy.spbstu.ru/article/2012.27.6/
06.pdf
RAR
RUS
53-73
56091980300
0000-0003-3850-424X
Lalin
Vladimir
Peter the Great St. Petersburg Polytechnic University
vllalin@yandex.ru
29 Politechnicheskaya St., St. Petersburg, 195251, Russia
56296687300
0000-0002-2299-3096
Rybakov
Vladimir
Peter the Great Saint Petersburg Polytechnic University
fishermanoff@mail.ru
Polytechnicheskay, 29
Morozov
S.
Peter the Great Saint Petersburg Polytechnic University
ksenbor@gmail.com
Polytechnicheskay, 29
The Finite Elements Research for Calculation of Thin-Walled Bar Systems
This article is written to continue the article of recent issue of the journal (Lalin V.V., Rybakov V.A. The finite elements for design of building walling made of thin-walled beams) considered the creating of 4 types of finite elements – depending on a way of function approximation of deformations (torsion and warping):
1. Linear approximation of torsional functions with a 2-central finite element having 4 transitions; 2. Square-law approximation of torsional functions and linear approximation of warping function with a 3-central finite element having 5 transitions;
3. Square-law approximation of functions of torsional and warping functions with a 3-central finite element having 6 transitions
4. Cubical approximation of functions of torsional with a 2-central finite element having 4 transitions
In the article we continue realization of finite elements method algorithms and we consider some test examples about the torsion of the thin-walled beam having various boundary conditions on the ends. Also the given problems are considered from the point of view of search of static power factors at the constrained torsion: a bimoment, a sectorial torsion moment and the moment of free torsion.
Formulas for cross-sectional form for channel influence factor calculation, which are necessary for application of the semisheared theory of thin-walled beams, are received. Analytical decisions for the basic power factors and deformations under the semisheared theory for simple schemes most often meeting in engineering practice loaded by in regular intervals distributed loading with excenterisity are received. Convergence of the offered finite elementswhich speed depends on the type of basic functions approximation is shown on concrete examples.
Recommendations and conclusions concerning application of various finite elements are formulated.
10.5862/MCE.27.7
torsion
warping
interpolation polynomials
shear deformation
bimoment
stiffness matrix
factor оf cross-section influence
https://engstroy.spbstu.ru/article/2012.27.7/
07.pdf
RAR
RUS
74-78
Kagan-Rosenzweig
Lev
Saint-Petersburg State University of Architecture and Civil Engineering
Kagan_R@mail.ru
About stability analysis of elastic frames
This article illustrates a simple method of stability analysis for elastic frames loaded with dead and follow forces. In its undisturbed state, frame elements might undergo not compression only but bending and torsion as well. It is shown that for simple frames there is no necessity of program complexes using. For conservative systems the problem is formulated as a problem of equilibrium bifurcation. For non-conservative systems, dynamical approach is applied. The suggested method is used for calculation of coefficients in equations of motion.
10.5862/MCE.27.8
stabilityof frames
bifurcation
method of analysis
https://engstroy.spbstu.ru/article/2012.27.8/
08.pdf
RAR
RUS
79-90
Zhgutov
Vladimir
"Kitezh" LLC Architecture and Construction Company
abc.kitezh@gmail.com
St. Petersburg, Russia
Mathematical deformation models of variable thickness shells with calculation of different materials` behaviour
Shells as elements of various structures are widely used in different fields of engineering and construction. Thin-walled elements of modern structures that represent shells designed to work under the influence of mechanical stress, which can be either static or dynamic. Calculations of strength, stability and vibrations of shell structures have an important role in the design of modern devices, machines and constructions. Profile of shell can have smooth thickening to increase rigidity in some areas. There is also a variant of a thin-walled part of the shell strengthening by discretely spaced ribs.In both cases, carrying force of structures significantly increases with a slight increase of its mass. In this article geometrically nonlinear mathematical deformation models of shells with variable thickness, in particular ribbed shells, (for static and dynamic problems) are proposed. Different material properties are taken into account (orthotropism, linear and nonlinear elasticity, viscoelasticity and creeping), as well as transversal movements, variable rigidity of ribbed shells besides its finite widths and height of ribs, shear and torsion rigidity.
10.5862/MCE.27.9
variable thickness shells
linear and nonlinear elasticity
viscoelasticity
transversal movements
full shear angles
variable rigidity
shear and torsion rib rigidity
full deformation energy functional of shells
https://engstroy.spbstu.ru/article/2012.27.9/
09.pdf
RAR
RUS
91-97
Denisov
Grigoriy
Peter the Great Saint Petersburg Polytechnic University
oxoxox@mail.ru
Polytechnicheskay, 29
56091980300
0000-0003-3850-424X
Lalin
Vladimir
Peter the Great St. Petersburg Polytechnic University
vllalin@yandex.ru
29 Politechnicheskaya St., St. Petersburg, 195251, Russia
About the continuous spectrum of vibrations of beam construction elements under high-frequency effects
In this paper the high-frequency vibrations of beam structural elements on the example of cantilever rod are analyzed. The purpose of this article is to show the existence of the boundary frequency, above which the structure behaves as a system with a continuous spectrum, on elementary examples and to demonstrate the possibility of using this fact during engineering calculations performing. With the help of mathematical transformations and numerical experiments the existence of simple beam structures mixed spectrum, formed by the discrete and continuous parts, is shown. It is also shown that there is a boundary frequency that separates the portions of the spectrum and determines the upper frequency limit of the external effects, for which it is necessary to conduct dynamic account of structures. In this case the amplitude of the vibrations with a frequency exceeding the boundary one does not depend on the dynamic characteristics of the rod, but it is mostly determined by the static characteristics of the rod and the load.
10.5862/MCE.27.10
high-frequency vibrations
continuous spectrum
discrete spectrum
rod
boundary frequency
https://engstroy.spbstu.ru/article/2012.27.10/
10.pdf
RAR
RUS
98-105
Serazutdinov
M.
Kazan national research technological university
Ubaydulloyev
Madzhid
Kazan National Research Technological University
madgidpwn@rambler.ru
Strengthening of the beam structures taking into account repair and mounting forcesinfluence
In the article the variation method of calculation of the loaded statically indeterminable structures strengthened by increasing the section of elements and the constructive and design model of structures modifying by installation of additional elements is presented. The procedure of the stress-strain state of the strengthened loaded structures determining, taking into account the repair and mounting stresses and also attached additional elements is presented. Computer program, which is based on the described methodology and allows to simulate the strengthened structure and to determine its stress-strain state at various stages of considering the deformation and stress during the current action of strengthening is composed. Reliability and high accuracy of calculations made by this program are established by comparing them with the data of test examples and solution problems, which were obtained by other methods.
10.5862/MCE.27.11
strengthening
repair stress
mounting stress
variational method
https://engstroy.spbstu.ru/article/2012.27.11/
11.pdf
RAR
RUS
106-112
Braila
Natalya
Peter the Great Saint Petersburg Polytechnic University
nashi-n-v@mail.ru
Polytechnicheskay, 29
Analysis of mathematical expectations of the cracks parameters from the degree of element deterioration based on historical data processingabout similar objects
Technical survey of the real estate object may be carried out for its cost evaluating or for the defining necessity of repair. During the inspection special attention is paid to cracks that are important destructive defects of structural elements. The article includes a short description of the cracks formation and material destruction processes with specifying the main theories and formulas of the fracture mechanics. The mathematical expectations of the crack parameters were deducted. These dependencies are inserted into a system of building technical condition graphic models and embedded in a methodical complex of object technical condition evaluation taking into account visualization of defects. Such parameters of building quality as operational reliability and environmental safety are assessed by degree of fracturing factor. This factor displays not only the relative area of cracks in the walls but also the operational quality of the building in the following way: the fracturing factor indicates the degree of constructions resistance to such harmful micro-organisms like mold and fungi, which provoke damage to structures, impair indoor climate of rooms and cause building occupants diseases. The technical condition and estimated cost of structures physical deterioration removal are represented by the buildings structural elements circle chart.
10.5862/MCE.27.12
technical survey
crack
the stress intensity factor
physical deterioration
degree of fracturing factor
operational quality
https://engstroy.spbstu.ru/article/2012.27.12/
12.pdf