75504
2712-8172
Magazine of Civil Engineering
5
73
2017
1-112
RAR
RUS
3-13
57191530761
0000-0002-4765-5819
Alekseytsev
Anatoly
Moscow State University of Civil Engineering (National Research University)
aalexw@mail.ru
Moscow, Russia
Kurchenko
Natalia
Bryansk State University of Engineering and Technology
inserpik@gmail.com
Deformations of steel roof trusses under shock emergency action
The problems of experimental and theoretical research on the stressed and deformed state of steel structures under emergency actions are particularly relevant. Тhis paper proposes experimental and theoretical research methodology, which is used on the basis of an example of research on a full-length truss as part of the frame for an industrial buildings workshop. Components of the stressed-strained state of the structure are determined experimentally in the course of a simulated emergency situation. As emergency impacts, this paper considers the detachment of the air-cooling unit attached to a node of the lower chord of the truss. Experimental data is gathered through the joint use of the crate system, cable sensor and PC. The finite-element modelling of the structure behavior is performed based on the direct integration of differential equations of motion of the system subject to the local dynamic effects, and a comparison of data obtained with experiments results. As a result of using the test methodology we obtained the maximum weight of technological equipment fastened to the roof truss, while ensuring its normal operation in case of an emergency related to the failure to affix the equipment.
10.18720/MCE.73.1
truss
technological equipment
emergency impact
experiment
shock effects
crate system
cable sensor
dynamic loads
displacements in time
strains in time
https://engstroy.spbstu.ru/article/2017.73.1/
RAR
RUS
14-24
Bogdanov
Ruslan
Kazan State University of Architecture and Engineering
bogdanov.r.r@yandex.ru
56504969400
0000-0001-8879-1190
Ibragimov
Ruslan
Kazan State University of Architecture and Engineering
rusmag007@yandex.ru
Kazan, Russia
Process of hydration and structure formation of the modified self-compacting concrete
The article reviews the research results of influence of a complex modifying agent on rheological properties of cement-water paste and cement stone strength. The article describes the processes of hydration and structure formation of cement stone, the special aspects of the phase constitution of Portland cement hydration products in the process of modifying by complex admixture. The behavior of cement hydration in composition with the complex modifying agent have been shown by means of measuring the hydrogen-ion concentration, by sedimentation, contraction and heat emission of cement suspension. There is the decreasing of the degree of cement stone hydration because of blocking action of the superplasticizing admix and hydrophobisator during the initial stage. Studying the cement stone spalls with the aid of electron microscopy has showed that there are the crystallized hydrated newgrowths with smaller dispersive capacity in composition with the complex modifying agent than the ones without introduction of admixtures. The increasing of concentration of hydrated calcium sulfoaluminate in pores and capillaries, the increasing of the specific surface area of hydrated phases both in the general structure of cement stone and in structure with regions of imperfections, the voids content decreasing lead to the material hardening. The way of cement stone structure formation in composition with the complex modifying agent is found by means of differential thermal and X-ray phase analyses. This way is shown in the composition with a complex modifying agent manifested in blocking effect SP and HP, resulting in a reduced amount of portlandite and high content of the starting phase the cement clinker, wherein the MTK is reacted with calcium hydroxide, which helps to seal material. Reduction of ettringite in the composition with a complex modifying agent is associated with precipitation of superplasticizing admix molecules on C3A particles, which limits interaction with water.
10.18720/MCE.73.2
modifying
admixture
superplasticizing admix
hydrophobisator
metakaolin
self-compaсting concrete
hydration
https://engstroy.spbstu.ru/article/2017.73.2/
RAR
RUS
25-39
Tusnina
Valentina
National Research Moscow State Civil Engineering University
valmalaz@mail.ru
Semi-rigid steel beam-to-column connections
Steel frameworks are widely used construction of multistory buildings for different purposes. In the practical framework calculations, the girder-column joint connections are taken as either absolutely rigid or hinged ones. The analysis of the actual behaviour of the frame joint connections shows that they normally occupy an intermediate position in the joints classification into "rigid" and "hinged" ones, i.e. they have certain pliability. Such pliability is characterized by different grades of stiffness that depends on a specific design solution of a joint. Therefore, to avoid possible material errors, the statistical calculations of frames should consider layouts with the joints that are able to support the corresponding amount of bending moments. This article contains the results of experimental and theoretical research of the actual behaviour of the girder-column connection semi-rigid joints using ABAQUS 6.13 computing complex, which enables us to solve problems by the finite elements method with due regard to the geometrical and physical nonlinearity. We consider the design of a beam-to-column connection with connecting elements in the form of paired vertical angles bolted to the beam wall and to the column flange. Based on the comparative analysis of the results of the numerical analysis and on the experimental data, the actual behaviour of the structure has been found and the stiffness of the joint type to be considered has been determined.
10.18720/MCE.73.3
semi-rigid joint
steel frame
beam
stiffness
rotational angle
support moment
https://engstroy.spbstu.ru/article/2017.73.3/
RAR
RUS
40-48
56426211200
0000-0002-3541-0072
Petrichenko
Mikhail
Peter the Great Saint Petersburg Polytechnic University
fonpetrich@mail.ru
Polytechnicheskay, 29
Subbotina
Svetlana
Peter the Great Saint Petersburg Polytechnic University
svetlana.subbotina94@mail.ru
Polytechnicheskay, 29
Khairutdinova
Faina
Peter the Great Saint Petersburg Polytechnic University
faina.spbstu@gmail.com
Polytechnicheskay, 29
Reich
Elizaveta
Peter the Great Saint Petersburg Polytechnic University
lisa_reich@mail.ru
Polytechnicheskay, 29
56227381900
0000-0003-2673-4566
Nemova
Darya
Peter the Great Saint Petersburg Polytechnic University
darya.nemova@gmail.com
Polytechnicheskay, 29
Olshevskiy
Vyacheslav
Peter the Great St. Petersburg Polytechnic University
79119199526@yandex.ru
29 Politechnicheskaya St., St. Petersburg, 195251, Russia
AAU-2845-2020
57204362749
0000-0002-6289-325X
Sergeev
Vitaliy
Peter the Great St. Petersburg Polytechnic University
vicerector.sc@spbstu.ru
St. Petersburg, Russia
Effect of rustication joints on air mode in ventilated facade
Ventilated facade is a contemporary facade system that is popular due to its energy efficiency. There are different configurations of the façade systems, among other things, various spacing between rustication joints. Cold air penetrates through them, thereby, influences air circulation. In this paper, theoretical estimate of air flow data is carried out by applying Boussinesq's hydrostatic model. Research of an impact of rustication joints interval on air flow data via physical simulation is performed for different façade configurations. Based on the results obtained, the most optimal solution is the design of a ventilated facade without rustication joints, or with the largest joints interval value.
10.18720/MCE.73.4
ventilated faсade
enclosing structure
heat-gravitational motion
average velocity
ventilated air gap
energy efficiency
https://engstroy.spbstu.ru/article/2017.73.4/
RAR
RUS
49-61
Danilevski
Leonid
State enterprise "NIPTIS Housing Institute named after Ataev S.S."
leonik@tut.by
Danilevsky
Sergey
State enterprise "NIPTIS Housing Institute named after Ataev S.S."
niptis-7@tut.by
The algorithm and accuracy of definition of heattechnical indicators of buildings
The object of the given research is the thermotechnical characteristics of buildings. The problem of thermotechnical indicators measurement arises at the acceptance of the buildings in use and also while performing work on energy classification of buildings in use. The two-level procedure of specific consumption definition of thermal energy for heating is offered: the coefficient of heat losses of the building is defined, and then the specific consumption of thermal energy for heating for settlement conditions is estimated. The given article suggests the optimal algorithm of the coefficient of heat losses determination according to the consumption of thermal energy for the buildings, not depending from the outdoor air temperature and the power of household thermal emissions of the building. There are also the results of the estimation of the coefficient of the coefficient of heat losses and specific consumption of thermal energy for heating for the conditions estimation according to the long-term observation for highrise buildings. There are also the estimation of the RMS error of determining the coefficient of the coefficient of heat losses and specific thermal energy consumption for heating for the conditions estimation, as well as the 75 % confidence interval for this indicator. The results can be used for the buildings in use energy classification.
10.18720/MCE.73.5
specific consumption of thermal energy on heating
settlement service conditions
measurements
coefficient of specific heatlosses
statistical characteristics
classification of buildings
https://engstroy.spbstu.ru/article/2017.73.5/
RAR
RUS
62-69
0000-0003-2533-9732
Samarin
Oleg
National Research Moscow State Civil Engineering University
samarin-oleg@mail.ru
The probabilistic-statistical modeling of the external climate in the cooling period
Currently, the successful development of construction industry depends on the improved energy performance of buildings, structures and facilities, as well on the quality estimation of the outdoor climate. The problem of feasibly more accurate determination of energy consumption by climatic systems in buildings is a very high-priority task now because of decrease of energy and fuel sources and because of actualization of building standards in many countries. That is why it is very important to find simple but enough accurate dependences between climatic parameters in the heating as well as in the cooling seasons of a year. In the paper the modern principles accepted in different countries for the selection of the design climate information for the design of building envelopes and systems to ensure building microclimate are considered. Main shortcomings of the methods, including the concept of "typical year", are shown and the advantages of generating climate data arrays programmatically with the use of a pseudorandom number generator are described. Some results of the calculation of current temperature of the external air during the warm period of the year with different safety are presented using numerical modeling with Monte-Carlo procedure. The possibility of practical implementation of probabilisticstatistical principle of climatic data for some calculations relating to climatic systems and thermal regime of the building are shown. The comparison of the obtained values with the analytical expression for the normal distribution of random variables is presented and relationships for the selection of its main parameters according to the existing climatic manuals are proposed.
10.18720/MCE.73.6
probabilistic-statistical model
climate
typical year
safety index
Monte-Carlo procedure
temperature
the cooling period
https://engstroy.spbstu.ru/article/2017.73.6/
RAR
RUS
70-87
57196066346
0000-0002-8051-5914
Denisov
Aleksandr
National Research Moscow State Civil Engineering University
den-al-v@inbox.ru
Moscow, Russia
The impact of superplasticizers on the radiation changes in Portland cement stone and concretes
The authors have estimated the effect of advanced superplasticizers of types Muraplast, Reamin, Weiss SM, Polyplast SP-1 and Melflux on radiation changes in Portland cement stone and concretes of radiation protection, based on experimental data from available literature, about the effect of such superplasticizers on thermal changes of Portland cement stone and the known analogy between thermal and radiation changes in Portland cement stone exposed to neutrons. The estimate of radiation changes in volume and compression strength of Portland cement stone used proposed ratios between the effect of superplasticizers on thermal and radiation changes in Portland cement stone, obtained through processing the published experimental results about the effect of superplasticizers S-3 and S-4 on radiation and thermal changes in Portland cement stone. Radiation changes in volume, crack formation, compression strength and deformation modulus of concretes, were measured with developed and tested methods for analysis of radiation changes in concretes based on information on changes of their components (aggregates and Portland cement stone). It has been established that advanced superplasticizers generally diminish radiation changes in Portland cement stone and concretes. The authors have demonstrated the extent by which such changes are reduced depending on various factors. It has been found that the effect of superplasticizers is in inverse proportion to the water-to-cement ratio of the mix as cement stone is made, by increasing the content of superplasticizer in the mix (for water reducing), and it depends on the fluency of fast neutrons.
10.18720/MCE.73.7
superplasticizers
Portland cement stone
concretes
civil engineering
radiation changes in volume
strength and deformation modulus
effect of neutron radiation from nuclear reactors
https://engstroy.spbstu.ru/article/2017.73.7/
RAR
RUS
88-95
Al Ali
Mohamad
Technical University in Košice
mohamad.alali@tuke.sk
Bajzecerova
Viktoria
viktoria.bajzecerova@tuke.sk
Kvocak
Vincent
Technical University in Košice
vincent.kvocak@tuke.sk
Design methods of timber-concrete composite ceiling structure
Timber-concrete composite structural members are increasingly used in the case of restoration of wooden ceilings. In the other hand, their use also increases in the case of new buildings. Design methods of the composite structures have been evolving since their first use. This expressive evolution of design methods is related to extensive research in this area in last three decades. This paper presents basic information about realisation, experimental and numerical analysis of timber-concrete composite ceiling with nail connections. The design of the mentioned ceiling was realised according to the relevant standards and recommendations in that time. The paper also presents a comparison between the design results of this composite ceiling and deflections measured during experimental short term loading process with the currently widely used analytical calculation model, so called γ-method. This method takes into account the joint compliance of the used nails. In addition, creep behaviour of used materials and concrete shrinkage were implemented in this calculation model. Comparison of the numerical and experimental results shows, that the current method better reflects the real stiffness of the ceiling structure. On the base of mentioned calculation model, the final deformation of the ceiling was also predicted.
10.18720/MCE.73.8
timber-concrete
сomposite structures
Design methods
γ-method
https://engstroy.spbstu.ru/article/2017.73.8/
RAR
RUS
96-112
6506150284
0000-0003-1139-3164
Sainov
Mikhail
Moscow State University of Civil Engineering (National Research University)
mp_sainov@mail.ru
Moscow, Russia
Lubyanov
Vladislav
National Research Moscow State Civil Engineering University
lubyanovvv@yandex.ru
Stress-strain state of seepage-control walls in foundations of embankment dams
Results are considered of systematic study of stress-strain state (SSS) of a seepagecontrol wall arranged in the embankment dam foundation. The following factors affecting the wall SSS were studied: the wall depth, deformation modulus of the wall material, the pattern of the wall resting. Studies were conducted with the aid of numerical modeling. They revealed significant role of friction processes and slippage at the contact with soil on the wall SSS formation. It is friction through which soil transfers to the wall the compressive longitudinal forces which increase while the wall stiffness increases. It was also revealed that conditions of operation of suspended walls are more favorable that those of walls resting on rock. Empirical formulae were proposed which permit predicting the value of maximum compressive forces in the wall. Compressive strength of the wall was assessed. At that, it was taken into account that strength of plastic clay-cement concrete considerably increases if it is compressed from all sides as compared to uniaxial compression. A considerable role of accounting this effect was shown at selecting material for arrangement of the wall. It was obtained that to provide the wall strength it is necessary to have its material deformability exceeding the deformability of the surrounding soil not more than 5 fold. It was revealed that at perceiving by the wall the horizontal forces of seepage or hydrostatic pressure the longitudinal forces in it sharply decrease. It was obtained that then there is a danger of the wall tensile stress failure, because bend deformations in the wall cause irregular distribution of stresses in it. Especially it is hazardous for the walls made of rigid materials.
10.18720/MCE.73.9
cut-of wall
stress-strain state
clay-cement concrete
numerical modeling
strength
https://engstroy.spbstu.ru/article/2017.73.9/