scholarly journals Seismic behavior of the main girder of a bridge with viscoelastic dampers

Vestnik MGSU ◽  
2021 ◽  
pp. 809-818
Author(s):  
Aleksey A. Loktev ◽  
Ahmad Barakat ◽  
Jaafar Qbaily
Keyword(s):  
Seismic Effect ◽  
Seismic Stability ◽  
Viscoelastic Dampers ◽  
Bridge Girder ◽  
Seismic Displacements ◽  
Seismic Impact ◽  
Stiffness And Damping ◽  
Main Girder ◽  
Horizontal Displacements ◽  
Elastic Elements

Introduction. The seismic stability of bearing structures is one of the main objectives of design and construction of structures in earthquake areas. The co-authors have analyzed the effect of a damper, located at the intersection of structural elements, on the seismic response of the main girder of a steel-concrete bridge exposed to the seismic impact. The purpose of this study is to select optimal values of viscous and elastic elements to ensure the seismic resistance of the bridge. Materials and methods. The finite element method was used to simulate the geometric characteristics of the bridge. The model of the bridge has rod elements to simulate girders and viscous elastic elements to simulate dampers. In the study, different values of elastic and viscous characteristics of the damper were used in pairs. The nonlinear problem statement helped to analyze the bridge structure using the direct dynamic method. Results. As a result, we obtained a graphic chart describing the relationship between horizontal displacements and the time for each pair of values of elastic and viscous characteristics of the damper for Maxwell and Kelvin – Voigt models. The effect of changes in the values of stiffness and damping parameters on the values of the period and eigenfrequencies of this superstructure was also investigated. Conclusions. The co-authors chose the damper parameters to minimize seismic displacements of the bridge girder and optimally suppress the dynamic interaction between the bridge elements. Viscoelastic elements of the Kelvin – Voigt type provide more regular values of horizontal displacements of the girder when the direction of the seismic effect changes. We also recommend to select the pair of values equal to 20 000 kN/m, 800 kN s/m, and to use the Kelvin – Voigt model in the design of a viscoelastic damper.

scholarly journals Analysis of blasting seismic impact on underground mining workings under the conditions of the Magnezitovaya mine

2020 ◽  
Vol 192 ◽  
pp. 01029
Author(s):  
Vyacheslav Kutuev ◽  
Pavel Menshikov ◽  
Sergey Zharikov
Keyword(s):  
Underground Mining ◽  
Seismic Effect ◽  
Industrial Safety ◽  
Seismic Stability ◽  
Dynamic Impact ◽  
Mining Operations ◽  
Slowing Down ◽  
Underground Workings ◽  
Mine Workings ◽  
Seismic Impact

Seismic impact of technological explosions on underground mining workings of the Magnezitovaya mine was assessed. Seismic stability of rocks of the Magnezitovaya mine was determined and safe distances from technological explosions have been calculated by the admissible seismic effect for rocks. URAN and Minimate Plus seismic recorders with three-component seismic receivers were used to establish the dynamic impact on the mine workings. Based on comparison of calculated values and experimental measurements, the recommendations are given for explosive mass limitation at a slowing-down stage at a level of minimum dangerous values for technological explosions in underground mine. It is established that the blasting operations carried out at the Magnezitovaya mine of PAO Magnezit Combine with fan longhole stopping were performed with the seismic impact safety of underground technological explosion and will not lead to the loss of rock mass stability near the underground workings. Relevance of these studies is to ensure industrial safety of underground mining operations.

scholarly journals Seismic stability of vibration-insulated turbine foundations depending on the frequency composition of seismic impact

2021 ◽  
Vol 17 (1) ◽  
pp. 30-41
Author(s):  
Aleksandr E. Babsky ◽  
Vladimir V. Lalin ◽  
Ilia I. Oleinikov ◽  
Vladimir A. Tarasov
Keyword(s):  
Power Plants ◽  
Time History ◽  
Axial Direction ◽  
Seismic Stability ◽  
Seismic Resistance ◽  
Seismic Action ◽  
Seismic Accelerations ◽  
Seismic Displacements ◽  
Seismic Impact ◽  
The Impact

The seismic resistance of vibration-insulated turbine foundations is a complex and multifaceted problem that includes many aspects. The turbine foundation is a special building structure that unites parts of the turbine and generator unit into a single machine and it is used for static and dynamic loads accommodation. The number of designed and constructed power plants in high seismic level areas is large and steadily growing. In addition, engineers and designers deal with the issue of the frequency composition of the seismic impact influence on the seismic resistance of vibration-insulated turbine foundations. Dynamic calculations were performed in Nastran software using time history analysis and the finite element method. The main criteria for the seismic resistance of a vibration-insulated turbine foundation are the values of the maximum seismic accelerations in the axial direction at the level of the turbine installation and the values of vibration-insulated foundation maximum seismic displacements (deformations of vibration isolators). The results of the calculation experiments proved a significant effect of seismic action frequency composition on the behavior of the vibration-insulated turbine foundations. Calculations of foundations, taking into account earthquakes of the same intensity, but with different values of the prevailing frequencies of the impact, lead to the differing by several times values of the maximum seismic accelerations at the turbine level and seismic displacements.

The Influence of Slab Concreting Sequence on a Continuous Composite Girder Bridge

2016 ◽  
Vol 691 ◽  
pp. 96-107
Author(s):  
Tomas J. Zivner ◽  
Rudolf B. Aroch ◽  
Michal M. Fabry
Keyword(s):  
Concrete Slab ◽  
Transverse Cross Section ◽  
Slab Thickness ◽  
Slab Width ◽  
Composite Girder ◽  
Steel Members ◽  
Composite Bridge ◽  
Bridge Girder ◽  
Girder Bridge ◽  
Main Girder

This paper deals with the slab concreting sequence and its influence on a composite steel and concrete continuous highway girder bridge. The bridge has a symmetrical composite two-girder structure with three spans of 60 m, 80 m, 60 m (i.e. a total length between abutments of 200.0 m). The horizontal alignment is straight. The top face of the deck is flat. The bridge is straight. The transverse cross-section of the slab is symmetrical with respect to the axis of the bridge. The total slab width is 12 m. The slab thickness varies from 0.4 m on main girders to 0.25 m at its free edges and 0.3075 m at its axis of symmetry. The center-to-center spacing between main girders is 7 m and the slab cantilever on either side is 2.5 m long. Every main girder has a constant depth of 2800 mm and the thicknesses of the upper and lower flanges are variable. The lower flange is 1200 mm wide whereas the upper flange is 1000 mm wide. The two main girders have transverse bracing at abutments and at internal supports and at regular intervals in every span. The material of concrete slab is C35/45 and of steel members S355. The on-site pouring of the concrete slab segments is performed by casting them in a selected order and is done after the launching of the steel two girder bridge. The paper presents several concreting sequences and their influence on the normal stresses and deflections of the composite bridge girder.

Dynamics of a Rotating Flexible Multi-Link With Viscoelastic Constraining Layers

1993 ◽  
Author(s):  
H. S. Tzou ◽  
G. C. Wan
Keyword(s):  
Vibration Control ◽  
High Precision ◽  
Structural Systems ◽  
Damping Properties ◽  
Passive Vibration Control ◽  
Viscoelastic Dampers ◽  
Viscoelastic Layers ◽  
Stiffness And Damping ◽  
Dynamics And Vibration

Abstract Due to an increased flexibility of modern mechanical and structural systems, effective vibration control becomes essential to their high-precision operations. In this paper, dynamics and vibration control of a rotating multi-link are studied. Passive vibration control of the link with distributed viscoelastic layers is studied. Effectiveness of the distributed viscoelastic dampers with various stiffness and damping properties is investigated.

Influence of underground mass explosion on protected objects of the industrial site in case of collapse of the interstory whole

2020 ◽  
pp. 368-382
Author(s):  
V. A. Kutuev ◽  
S. N. Zharikov
Keyword(s):  
Large Scale ◽  
Physical And Mechanical Properties ◽  
Underground Mine ◽  
Seismic Stability ◽  
Experimental Measurements ◽  
Industrial Site ◽  
Close Proximity ◽  
Ground Conditions ◽  
Seismic Vibrations ◽  
Seismic Impact

Within the boundaries of the mining branch of JSC Kyshtymsky MCC the underground large-scale blast was made to cave in the interstorey pillar with the maximum explosive weight 963 kg at the spacing stage. The Institute of Mining of Ural Branch of RAS has received a task to study the seismic impact of the underground large-scale blast on the protected objects of the industrial site of Kyshtymsky underground mine located in the close proximity to the sites of blast works. The aim of the work is to determine the seismic stability of grounds on sites of the protected objects and the permissible values of vibration velocities for buildings of JSC Kyshtymsky MCC. It is also necessary to determine the permissible distances from the blast to the protected objects for 5 engineering-geological elements on the basis of physical and mechanical properties of deposit rocks. On the basis of the initial data, according to the method of the Institute of Mining of Ural Branch of RAS, the authors have performed a complex of calculations of seismic stability of grounds on sites of the objects to determine the permissible values of vibration velocities for buildings of JSC Kyshtymsky MCC. The authors have also performed a multiversion calculation of permissible distances from the blast to the protected objects for 5 engineering-geological elements (EGE) depending on the the explosive weight at the spacing stage, the coefficient of ground conditions and the permissible velocity of seismic vibrations. As a result of comparison of the calculated values and experimental measurements, the recommendations have been given to establish the limitation of the explosive weight at the spacing stage to the level of minimum hazardous values during the large-scale blasts in the underground mine.

Study on mechanical properties of high damping viscoelastic dampers

2019 ◽  
Vol 22 (14) ◽  
pp. 2925-2936 ◽  
Author(s):  
Yun Chen ◽  
Chao Chen ◽  
Qianqian Ma ◽  
Huanjun Jiang ◽  
Zhiwei Wan
Keyword(s):  
Mechanical Properties ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Hysteretic Behavior ◽  
Loading Frequency ◽  
Equivalent Stiffness ◽  
Viscoelastic Dampers ◽  
Wide Range ◽  
High Damping Rubber ◽  
Stiffness And Damping

The mechanical properties of the viscoelastic damper made of high damping rubber produced in China are investigated in order to provide the basis for its application. At first, the test on material properties of high damping rubber is conducted. The Mooney–Rivlin model, the Yeoh model and the Prony series are applied for simulating the nonlinear behavior of the high damping rubber with the aid of software ABAQUS. Then, three viscoelastic dampers with different sizes are tested under cyclic loading. The effects of strain amplitude and loading frequency on hysteretic behavior of dampers are analyzed. Viscoelastic dampers possess large deformation capability, stable energy-dissipation capacity and good fatigue-resisting property. The effect of strain amplitude is much more significant than loading frequency. The hysteretic behavior of the dampers is simulated by the Bouc–Wen model and the model of the equivalent stiffness and damping, respectively. The prediction results by using the Bouc–Wen model are in good agreement with the experimental results, which indicates that the Bouc–Wen model is applicable to simulate the mechanical properties of high damping viscoelastic dampers with a wide range of shear strain. As to the model of equivalent stiffness and damping, it has the advantages of clear concept and simple calculation. However, the good accuracy of prediction can be obtained only when the shear strain is not greater than 60%.

Seismic Behavior of Shifang Telecom Building under Conventional Earthquakes

2010 ◽  
Vol 163-167 ◽  
pp. 4227-4231
Author(s):  
Xiao Hu ◽  
Yong Tao Gao
Keyword(s):  
Numerical Simulation ◽  
Spectrum Analysis ◽  
Seismic Behavior ◽  
Time History ◽  
Internal Force ◽  
Seismic Effect ◽  
Time History Analysis ◽  
History Analysis ◽  
Seismic Impact

To study the seismic behavior under conventional earthquakes, according to a case of Shifang Telecom Building (STB) under 5.12 earthquake, this paper makes the computation of internal force and deformation of structure; then compares the seismic behavior of two different models with spectrum analysis and time-history analysis. The conclusion shows that STB can approximately meet requirements for fortification against seismic impact under conventional earthquakes; the steel tower on top can amplify the seismic effect indeed and the weakness of numerical simulation tallies with the reality.

scholarly journals Investigating the seismic impact made by the underground large-scale blast on the secure facilities of Kyshtym GOK when caving the floor pillar

2020 ◽  
pp. 25-36
Author(s):  
Vyacheslav Kutuev ◽  
Keyword(s):  
Large Scale ◽  
Physical And Mechanical Properties ◽  
Underground Mine ◽  
Seismic Stability ◽  
Experimental Measurements ◽  
Industrial Site ◽  
Close Proximity ◽  
Ground Conditions ◽  
Seismic Vibrations ◽  
Seismic Impact

Introduction. Within the mining claim boundaries of Kyshtym GOK the underground large-scale blast was made to cave in the floor pillar with the maximum explosive weight of 963 kg at the spacing stage. The Institute of Mining UB RAS has received a task to study the seismic impact of the underground large-scale blast on the secure facilities of Kyshtym underground mine industrial site located in the close proximity to the sites of blast works. Research aim is to determine the seismic stability of grounds at the sites of the secure facilities and the permissible values of vibration velocities for Kyshtym GOK buildings. It is also necessary to determine the permissible distances from the blast to the secure facilities for 5 engineering-geological elements on the basis of physical and mechanical properties of rock. Research methodology. On the basis of the initial data, according to the method of IM UB RAS, ground seismic stability calculations have been made at the sites of the facilities to determine the permissible values of vibration velocities for Kyshtym GOK buildings. A multivariate calculation of permissible distances from the blast to the secure facilities for 5 engineering-geological elements (EGE) has also been made depending on the explosive weight at the spacing stage, the coefficient of ground conditions and the permissible velocity of seismic vibrations. Results. The actual velocities of earthquake vibrations were determined by the results of experimental measurements using Minimate Plus and URAN seismic recorders, the values of which did not exceed the permissible velocities of ground motion in the base of buildings. Summary. As a result of comparing calculated values and experimental measurements, the recommendations have been given to establish the limitation of the explosive weight at the spacing stage to the level of minimum hazardous values during the large-scale blasts in the underground mine.

scholarly journals METHODS FOR CALCULATING DYNAMIC SYSTEMS WITH ELASTOMERIC SUPPORTS UNDER SEISMIC IMPACTS OF THE "PROJECT EARTHQUAKE" LEVEL»

2020 ◽  
Vol 8 (3) ◽  
pp. 23-28
Author(s):  
Maksim Zubrickij ◽  
O. Ushakov ◽  
Linar Sabitov ◽  
A Sagabiev
Keyword(s):  
Surface Area ◽  
Dynamic Systems ◽  
Dynamic Method ◽  
Main Tool ◽  
Seismic Stability ◽  
Earthquake Resistant ◽  
The Difference ◽  
Seismic Impact ◽  
Isolated Systems ◽  
Seismic Impacts

The article provides a brief overview of methods for assessing the seismic stability of systems using elastomeric supports under seismic impacts of the "Project earthquake" level. As part of the study, a set of dynamic and static calculations was performed, and two methods for calculating earthquake-resistant systems were considered: the linear-spectral method (LSM) and the direct dynamic method (PDM). The purpose of the research is to assess the possibility of using LST for seismic impacts of the PZ level on systems with elastomeric supports. It was found that the difference in the results of calculations for the two methods does not exceed 12 %. Thus, the SHEET can be used as the main tool for calculating seismically isolated systems under the seismic impact of the earth's surface area.

scholarly journals SEISMOLOGICAL MONITORING OF INDUSTRIAL EXPLOSIONS AS AN EFFECTIVE APPROACH TO MONITORING SEISMIC EXPOSURE ON BOWELS

2019 ◽  
Vol 2 (2) ◽  
pp. 56-66
Author(s):  
Alexander Emanov ◽  
Aleksey Emanov ◽  
Nikolay Serezhnikov ◽  
Alexander Fateev ◽  
Uliana Vorona ◽  
...  
Keyword(s):  
Western Siberia ◽  
Seismic Effect ◽  
Total Charge ◽  
Technogenic Impact ◽  
Use Of Data ◽  
Seismological Data ◽  
Seismic Impact

For Kuzbass, based on the use of data from the registration of industrial explosions, a network of seismological stations and information on the parameters of explosions received from mining enterprises has created a system that allows monitoring the effectiveness of short-delayed blasting in reducing seismic impact on the subsoil. Theoretically, any charge can be distributed so that the seismic effect does not depend on the total charge of the explosion, but is determined by the charge of the stage. It has been experimentally shown that explosions with a smaller total charge explode with a greater seismic effect than explosions with the largest charges. The reasons for this result have been revealed and a system has been created for monitoring errors in blasting operations on cuts. Seismological data allows you to control the technogenic impact of explosions in Western Siberia and provide information for its reduction by correcting errors in the schemes of short-delayed blasting.

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