№6 2019
№6 2019

№6 2019

№6 2019

Content




read more


Dynamics of the Object of Polygon of Seismic Isolation: Building with Supports on Fluoroplastic Gaskets

Authors:    Vladimir A. Lapin    Yerzhanov S.Е.   
Rubric:     Seismic safety and seismic isolation of buildings   

read more

To study the seismic insulating properties of buildings in Almaty there is a special polygon. It includes buildings with conventional strip foundations with a system of cross-belts, seismic kinematic and supports with PTFE gaskets. The buildings are equipped with stations of engineering and seismometric service (seismic stations 20,21,22). The results of experimental studies of the house on fluoroplastic gaskets, performed in the late 80s, are analyzed. The results are compared with the instrumental records of the earthquakes of May 31, 2012 and August 16, 2014. The period of maximum spectrum coincides with the resonance in the initial stages of vibration tests-0.44-0.47 seconds. Using a single-mass calculation scheme taking into account the presence of dry friction forces, the dynamic model of the building was calculated for the impact of an unsteady random process. The median acceleration values at the base correspond to the “Seismic Zoning Map of the Republic of Kazakhstan” for earthquakes with a frequency of 475 years and 2475 years. Probabilistic estimates of displacement values at the support level are obtained.


Dynamic Tests of the Administrative Building with a Stationary Seismic Isolation System in Irkutsk

Authors:    Khoroshavin Ye.A.   
Rubric:     Seismic safety and seismic isolation of buildings   

read more

The paper presents the results of dynamic tests of the administrative building with a stationary seismic isolation system on rubber-metal supports in Irkutsk by the method of standing waves. The dynamic characteristics of the building (periods, frequencies, amplitudes, phases of oscillations) for different forms of natural oscillations are determined. The comparison of the frequencies of Building 2 obtained by direct method with the calculated ones obtained at the design stage is carried out. The analysis of the influence of rubber-metal supports on the natural oscillations of Building 2 is carried out. The estimation of seismic stability of the building relative to the probable seismic loads is given.


On the Issue of Taking into Account Damping in the Assessment of Seismic Resistance of Structures

Authors:    Smirnova L.N.    Uzdin A.M.    Polorotova N.A.   
Rubric:     Theoretical and experimental studies   

read more

The authors present their view of the problem, with the frame of the discussion devoted to equations of seismic oscillations taking into account damping. The oscillation equations taking into account external and internal damping are written down. The cases of homogeneous and inhomogeneous acceleration field of the day surface along the length of the structure are considered.


The Most Important Aspects of Calculation and Designing the Basis of the Gravitational Supporting Wall for Seismic Load

Authors:    Minaev O.P.   
Rubric:     Theoretical and experimental studies   

read more

The article outlines the most important aspects and summarizes the main results of the calcula-tion and design of a gravitational retaining wall reinforced concrete corner with a front con-sole and massive reinforced concrete on the seismic load. A comparative analysis of the calcu-lations for the operational case with static and seismic load for a wide range of input data is given. It is emphasized that during the design of the base of the retaining wall it is not al-lowed to liquefaction the sandy soils of the backfill and cushion at its base, which will lead to a catastrophic loss of the bearing capacity of the base soils and the stability of the retaining wall. To increase the stability of the structure of sandy soils, the liquefaction process should be applied by effective vibrodynamic methods of their compaction, developed by the author.


Seismic Hazard of the Territory of Syria

Authors:    Aldrebi Ziad Ahmad   
Rubric:     Theoretical and experimental studies   

read more

In Syria there are a large number of architectural monuments, buildings and structures that have suffered as a result of past earthquakes and hostilities, such as the Great Mosque in Aleppo, the castle of Krak de Chevalier in the province of Homs, the triumphal arch in the city of Palmyra, etc. The situation is exacerbated the fact that a certain number of existing buildings and structures in Syria does not meet the modern requirements of anti-seismic construction. Therefore, information about the seismicity of Syria is very important for the preservation of monuments of architecture, buildings and structures in this country. For this purpose, the author conducted an analysis of the seismological situation in Syria. The data of historical and instrumental earthquakes in this territory were studied, a table with seismicity was compiled, by analogy with situational seismicity in the Russian Federation, for some large cities in Syria. Values of peak ground acceleration (PGA) were obtained for various earthquake recurrence periods.


Seismic Performance Evaluation of Soft Ground Storey RC Frame with Masonry Infill Considering Various Retrofit Strategies

Authors:    Faqiri A.    Rutman Yu.    Ivanov A.Y.   
Rubric:     Theoretical and experimental studies   

read more

There is a representation of seismic performance evaluation method with due regard to economic effect assessment, which consider different seismic retrofit strategies applying for reinforced concrete (RC) soft ground story building with masonry infilled frame in upper stories. The dependencies, which allows to estimate the influence of masonry infill panel, located between structural columns and beams inside the RC frame, on the strength and stiffness, are shown. The analytical model simulation approach, which consider the influence of masonry infill panel on seismic response of the frame, is demonstrated. The analytical dependency, which allows to select the optimal seismic retrofit scheme for this kind of building with due regard to economic consideration, is applied. Two seismic retrofit strategies are analyzed in this study among with non-retrofitted (typical) one, where the first represents the base isolation technique implementation, and the second is the ground story RC columns strengthening by increasing their cross-section and area of reinforcements.


Torsion of Symmetric Structures Located on the Various Systems of Seismic Isolation Subjected to Wave Passage Effect of Earthquake

Authors:    Bondarev D.E.    Simbort E.   
Rubric:     Theoretical and experimental studies   

read more

Mathematical model of structure located on various systems of seismic isolation such as laminated rubber bearings and pendulum bearings are considered. This model takes into account torsion of superstructure caused by rotational component of seismic excitation. Rotational component of seismic excitation reflects the wave nature of earthquake. This paper illustrates the torsional response of isolated structure.


About New Types of Reinforcing Rolled Metal for Earthquake Engineering

Authors:    Tihonov N.I.    Smirnova L.N.    Bubis A.A.    Tikhonov G.I.    Safonov A.A.   
Rubric:     Theoretical and experimental studies   

read more

As a result of the release of GOST 34028-2016 «Reinforcing bars for reinforced concrete structures» the manufacturability of new kinds of reinforcing bars, taking into account the needs of different areas of construction were increased. The materials of the present study prove the ability of reinforcement with a multi-row (six-row and screw four-row) arrangement of transverse ribs on its surface to maintain adhesion with concrete even at the stage of exceeding the limit values of deformation. This factor, as well as high endurance at cyclic dynamic effects, possibility of connection using couplings of four-row screw reinforcing bars and anchoring it with nuts, expands the possibilities of using the new valves not only in earthquake engineering, but also in nuclear power, transport and other types of construction. The new reinforcing bars of domestic production are able to gain a leading position not only in the domestic but also in foreign construction markets.


“Old” and “New” Nodes in Modeling of Complicated Soil Environment

Authors:    Tyapin A.G.   
Rubric:     Theoretical and experimental studies   

read more

Complicated soil environment” means that under the basement there is a certain finite soil volume with properties breaking horizontally-layered initial soil composition. The author discusses two alternatives in modeling such volume. The “old nodes” approach means that one and the same set of internal nodes is used both for the outcropped soil and for the substituting soil. The “new nodes” approach means that a new set of the internal nodes (with the same coordinates) is introduced for the substituting soil. The author shows that the difference in the results is caused by special feature of the SASSI program: after the outcrop the old internal nodes stay with certain “residual” non-zero stiffness. If the substituting soil
is hard enough, this difference is negligible: “new nodes” approach will not give new results. But in case of soft substituting soil this “residual” stiffness can spoil the results of the “old nodes” approach. In such cases the “new nodes” approach is justified in spite of the increase of the problem size. Combined Asymptotic Method (CAM) is extended for the case of the “new nodes” approach; the capability of CAM is further extended. The topic is important because of the implementation of the upgraded soil pads under the base mats of the heavy structures in seismic regions.


“Difficult” Questions of Development of Seismic Microzoning

Authors:    Aleshin A.S.   
Rubric:     Seismic zoning   

read more

The regulatory framework for earthquake-resistant construction in Russia has recently been supplemented by a number of new long-awaited documents. This seemingly positive phenomenon gave rise to a situation that in one article was not without reason called «normative chaos». This situation is largely due to the difference between the basic concepts and relations of new and familiar old normative documents, which generates a state in the mind, defined by psychologists as cognitive dissonance. Of course, this phenomenon is temporary and understandable, but for the case of examination and passage of working documentation, it is certainly harmful. This work aims, at least in part, to provide answers to questions.
The most important contradictions are briefly considered and reasoned answers to the questions are given. A complete analysis of the problems involved requires much more than the allowable size of the article.