Smirnova L.N.
Smirnova L.N.

Смирнова Л.Н. Smirnova L.N.
PhD


Publications

Calculation of Wave Velocities in Segmented Pipelines with Flexible Joints
Issue: №2 2020
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Engineering methods for finding the average (averaged) velocity of propagation of longitudinal waves in pipelines with flexible joints are presented. By accurate analysis of the problem of oscillations of a one dimensional periodically inhomogeneous structure it is shown that the results of engineering approaches for rod velocity are the first or long-wave asymptotic approximation which valid when the period of external influence (the length of the seismic wave) significantly exceeds the size of the periodicity cell of the pipeline (the length of the pipe with a joint). Thus, it is established that when this condition is met, the problem of pipeline dynamics with joints is reduced to a much simpler problem of vibrations of a homogeneous pipeline, the velocity of wave propagation in which is equal to the found average value.
Numerical examples are given that demonstrate a significant (sometimes by an order of magnitude) decreasing of the rod velocity in the presence of flexible joints.

Response Spectra Method for Extended Systems with Proportional Damping
Issue: №1 2020
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The application of the response spectra method for extended damped systems with a point support on the base is considered. The support excitations can be different. External and internal damping is taken into account, it being assumed proportional i.e. admitting an exact or approximate decomposition of motion according to the undamped system modes. It is noted that the presence of external damping leads to additional system perturbation, i.e. to additional members appearance in the right part of motion equations. It is shown that well-known formulas of the response spectra method for systems on a rigid platform are kept intact, but the vector of load projections on the directions of generalized coordinates is modified taking into account the influence of support displacements on generalized loads in the system.


Issue: №3 2018
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On the Issue of Taking into Account Damping in the Assessment of Seismic Resistance of Structures
Issue: №6 2019
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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.

About New Types of Reinforcing Rolled Metal for Earthquake Engineering
Issue: №6 2019
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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.

Statistical Modeling of the Earthquake Input
Issue: №5 2019
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The main problem of modeling statistical seismic vibrations is correct input accelerogram setting. The analysis of the known seismic input models showed the erroneousness of using them in analyzing seismically isolated systems. These statistical models allow one to obtain either reliable accelerations or reliable displacements. However, complicated input models do not quite correspond to real earthquakes. Energy characteristics were not considered at all in the problems of accelerogram statistical modeling. A new model of seismic input, including a random pulse, has been considered. Three parameters has been added to the input model: the magnitude Мw , the epicentral distance R, and the moment when the pulse appears. Varying these parameters within the set limits allows one to adjust additional input characteristics. An example of the proposed process is given.

XIII Russian National Conference on Earthquake Engineering and Seismic Zoning (with International Participation) 16th World Conference on Seismic Isolation, Energy Dissipation and Regulation of Dynamic Characteristics of Structures
Issue: №4 2019
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Issue: №3 2019
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About Requirements of New Normative Documents to Reinforcing of Reinforced Concrete Designs for Construction in Seismic Areas
Issue: №1 2019
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To meet the safety requirements in the design of reinforced concrete structures in seismically hazardous areas, it is important to ensure the dissipation of seismic input energy in structures when their progressive collapse is included. For this purpose, plastic deformation of the calculated sections of reinforced concrete structures with the opening of cracks in reinforced concrete is allowed much higher than the maximum permissible. These conditions can be met, when a number of design requirements are met. These requirements are reflected in regulatory documents for the design and manufacture of building structures and materials, including reinforcing bar. The article present a comparative analysis of the requirements that have recently been published at normative technical documents, namely the SP 14.13330 and the standard of the organization «Earthquake engineering», and also requirements of the state standard «Reinforcing bar for reinforced concrete design» in relation to design for seismically dangerous areas are stated and explained. So, as one of the possible options, the authors consider the advantages of using screw fittings, for connecting rods with screw fittings it is recommended to replace welded joints with screw couplings.

Some Features of Modeling Design Accelerograms
Issue: №1 2019
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Summary:  At present, calculation of structures using earthquake accelerograms is becoming more and more important. However, the problem of modeling design accelerograms causes debates and contains various suggestions based on contradictory assumptions. Therefore, the value of complicated and time-consuming dynamic calculations can be rather dubious. The paper deals with some parameters of modeling design accelerograms. It is shown that the widely used method of input generation, developed by A.A. Dolgaya, gives rather rough approximations of synthetic accelerograms to real 
ones due to the insufficient number of model parameters.

Estimation of Earthquake Stability of Being Built Open Way Railway Composite Arch Overpass of Tunnel Type
Issue:
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Estimation of earthquake stability of reinforced arch viaduct of tunnel type strengthened by corrugated metal arch structure has been carried out. The structure calculation has been done using the finite element diagram including railway the embankment, the composite arch and soil base. Along the contour of the design area was placed the damping boundary. Obtained system mode parameters (frequencies and damping) were used for generating design accelerograms. It is shown that in the process of strong earthquakes (MDE) in the arch impost and crown may occur plastic hinges. When this becomes the arch turn from hingeless one into two or three — hinge arch, but does not lose bearing capacity. The recommendations for the reinforcement of structures under consideration are proposed.

Calculating Steel Bridge Spans on Earthquake Loads
Issue:
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It is shown that in many cases while calculating bridge spans it is necessary to take into account the soil-structure interaction. If the pier is higher than 5 m, energy dissipation for the main oscillation mode is determined substantially by energy losses, caused by wave propagation in the soil base, thereby the dynamic ratio drops significantly. Furthermore, if a bridge span is shorter than 55 m and the base modulus of deformation Eo < 30 MPa, the force in the piers can be determined by the second mode, for which the superstructure and piers oscillate in antiphase. For bridges with spans over 80 m long at Eo > 30 MPa, seismic forces for spans and piers are determined by the first oscillation mode. 

Possibility of Using a Response Spectra Method for the Calculation of Structures with Mass Dampers of the Seismic Input
Issue:
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The possibility of using a response spectra method (RSM) for the calculation of structures with mass dampers (MD) is considered. It is shown that the Guide Lines SP 14.13330.2014 allows us to take into account the MD behavior and estimate its efficiency. However, it is impossible to optimize damping in the mass damper elements. To take into account the damping RSM, including amendments to the damping and the mode correlation, may be modified. In this case, satisfactory results are obtained when the relative weight of MD less than 0.7 and the construction damping of less than 0.3 (15% of the critical value). For the great mass of the MD optimum damping is more than 20% of the critical, and there is a need to consider the effect of modal damping.

Score reduction factor for calculating the pylons of bridges
Issue:
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The reduction factor K1 included in the formulas of Guidelines for calculating seismic loads for bridge piers has been evaluated. The dependence of the reduction factor on the ratio of pier reinforcement has been obtained. To this aim the non-linear finite element calculation of the pier under monotonous loading has been carried out and the elastic limit and damaging displacement has been obtained.

THE WAVE EFFECT IN THE POST OF VISCO-ELASTIC MIX
Issue:
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A mathematical model of the dynamic behavior for heterogeneous media under vibro-impact loading  using the Kelvin - Voigt viscosity model is developed. Explicit relations to find the dynamic characteristics of the medium such as the dynamic elastic modulus and dynamic viscosity are presented. A detailed analysis is performed to outline an influence of the wave processes in the media on the stress state in the concrete. Simulation results are presented and discussed with experimental ones.

Experimental study of steel towers sets of power lines for seismic regions
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The natural gas and oil located in remote areas are characterized by high seismicity, resulted in the necessity to apply various constructive solutions of power transmission line for their uninterrupted energy supply both before and during the earthquake and after it. Therefore, recently the problem of studying the behavior of different constructive solutions of sets of transmission towers under seismic input is a topical one. The paper presents the data of experimental studies on steel towers sets of power lines 6 -10 kV, intended for use in areas with seismicity of 7-9 earthquake magnitude on the MSK-64 scale. The tests were carried out in the testing laboratory of V. A. Koucherenko CREE TSNIISK in 2016. The method of testing and the results of experimental studies are presented.

Earthquake engineering of the Russian Federation as a priority direction of activity of JSC Research Center of Constructions
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a:2:{s:4:"TYPE";s:4:"HTML";s:4:"TEXT";s:882:"The article provides a brief historical background on the leading schools of earthquake-resistant construction and seismic isolation, formed on the basis of TsNIISK named after V.A. Coucherenko, JSC Research Center of Construction. A brief review of research works, monitoring and development of scientific and technical and regulatory documentation in the field of earthquake-proof construction, carried out by the institutes of JSC Research Center of Construction  in recent years is given. The purpose of these works was to solve the tasks set by the President and the Government of the Russian Federation in terms of ensuring the integrated seismic safety of the territory of the Russian Federation. Prospects are out lined and proposals are given by JSC Research Center of Construction on the further development of earthquake-resistant construction  in the Russian Federation.";}

16 European Conference on Earthquake Engineering

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The article provides information about the 16th European conference on earthquake engineering and the General Assembly of the European Association for earthquake engineering, which took place in Thessaloniki (Greece) from 18 to 21 June 2018.

The Refinement of the Model of Seismic Input for the Statistical Modeling of Structures

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The paper describes a statistical method taking into account the velocity pulse and the energy characteristics of the reference impact. An example of generation of an impact is also given, which includes the impulse component.

Taking into account the difference in the support excitation for multi-supported structures
Issue: #6-2021
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Three characteristics are proposed to describe the excitation differences under supports for calculating multi-supported structures. These characteristics include the non-synchronicity indicator t0, the incoherence indicator r and the non-uniformly scaled indicator z. The first characteristic shows the time shift between the excitations, the second characteristic shows the difference in the excitation frequency composition, and the third one shows the difference in the action amplitudes. To estimate the nonsynchrony index, two approaches have been proposed – maximizing the correlation function and minimizing the norm of the excitation difference. The proposed parameters fully characterize the acceleration inhomogeneity field at the construction site. However, they affect the system response in different ways. Small deviations in the index of excitation amplitudes z weakly reduce the structure response. As for the excitation incoherence, this effect can bring the system closer or away from resonance.