scholarly journals A Novel Negative Stiffness Amplification System Based Isolation Method for the Vibration Control of Underground Structures

2020 ◽  
Vol 10 (16) ◽  
pp. 5421
Author(s):  
Qingjun Chen ◽  
Yanchao Wang ◽  
Zhipeng Zhao
Keyword(s):  
Energy Dissipation ◽  
System Analysis ◽  
Underground Structure ◽  
Negative Stiffness ◽  
Enhancement Effect ◽  
Underground Structures ◽  
Isolation System ◽  
Negative Stiffness Device ◽  
In Series ◽  
Amplification System

Underground structures can be vulnerable during strong earthquakes, and seismic mitigation systems designed for these structures are instrumental in improving multiple aspects of seismic performance. To deal with this problem, a novel isolation system is proposed for underground structures, employing the incorporation of a negative-stiffness amplification system (NSAS) and an isolator. The proposed NSAS consists of the subconfiguration of a spring with positive stiffness in parallel with a dashpot, which is then in series with a negative-stiffness device. The mechanical model and physical realization of the NSAS are presented, based on which the energy-dissipation-enhancement mechanism of NSAS is detailed. On this basis, comprehensive parameter analyses were conducted between the NSAS isolation system and a conventional isolation system. Analysis results showed that the NSAS exhibited a significant energy-dissipation-enhancement effect, in which the series connection of the negative and positive stiffnesses amplified the dashpot’s deformation for enhanced energy-dissipation capacity and efficiency. Compared with a conventional isolator, the NSAS isolation system provided the underground structure with a multiperformance and multilevel mitigation effect, particularly yielding lower responses of displacement and shear forces at the same time. More vibration energy could be dissipated by NSAS, thereby alleviating the energy-dissipation burden of underground structures.

A Modular-Type Three-Axis Vibration Isolation System Using Negative Stiffness

2010 ◽  
Author(s):  
Md. Emdadul Hoque ◽  
Takeshi Mizuno ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Negative Stiffness ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Single Degree ◽  
In Series ◽  
Isolation Systems

A vibration isolation system is presented in this paper which is developed by the combination of multiple vibration isolation modules. Each module is fabricated by connecting a positive stiffness suspension in series with a negative stiffness suspension. Each vibration isolation module can be considered as a self-sufficient single-degree-of-freedom vibration isolation system. 3-DOF vibration isolation system can be developed by combining three modules. As the number of motions to be controlled and the number of actuators are equal, there is no redundancy in actuators in such vibration isolation systems. Experimental results are presented to verify the proposed concept of the development of MDOF vibration isolation system using vibration isolation modules.

Experimental Shake Table Testing of an Adaptive Passive Negative Stiffness Device within a Highway Bridge Model

2015 ◽  
Vol 31 (4) ◽  
pp. 2163-2194 ◽  
Author(s):  
Navid Attary ◽  
Michael Symans ◽  
Satish Nagarajaiah ◽  
Andrei M. Reinhorn ◽  
Michael C. Constantinou ◽  
...  
Keyword(s):  
Numerical Models ◽  
Shaking Table ◽  
Negative Stiffness ◽  
Highway Bridge ◽  
Viscous Dampers ◽  
Isolation System ◽  
Bridge Model ◽  
Negative Stiffness Device ◽  
Model Components ◽  
Isolated Bridge

The implementation of a mechanical negative stiffness device (NSD) within a reduced-scale highway bridge model and its performance under seismic loading conditions is evaluated via shaking table tests. Four different isolation system configurations are considered: isolated bridge (IB), IB with viscous dampers, IB with NSDs, and IB with viscous dampers and NSDs. In addition, two bridge pier configurations were considered: one with flexible piers (mimicking a middle span of a multi-span bridge) and one with braced piers (mimicking a single span bridge supported on abutments). The main feature of the NSD is a large pre-compressed spring, which can push the structure away from its initial undeformed position and thus induce negative stiffness behavior. The experimental results clearly demonstrate the effectiveness of the NSDs in limiting the seismic response of the bridge and provide validation of numerical simulation results wherein numerical models of the bridge model components were calibrated via system identification testing.

scholarly journals Utilization of Building Information Modeling for Arranging the Structural Kingposts

Buildings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 323
Author(s):  
Vachara Peansupap ◽  
Pisal Nov ◽  
Tanit Tongthong
Keyword(s):  
Underground Structure ◽  
Visual Programming ◽  
Information Modeling ◽  
Construction Technology ◽  
Underground Structures ◽  
Building Information Modelling ◽  
Engineering Knowledge ◽  
Building Information ◽  
Rule Based Approach

The kingpost was a vertical element that was used to support the structural strut in the deep excavation. The structural kingpost was commonly arranged by experienced engineers who used two-dimensional construction drawings. Thus, it was still time-consuming and error-prone. Currently, an available construction program has been developed to arrange the structural kingpost by identifying the clash problems in the 3D environment. However, they have a limitation for detecting the clash that was unable to visualize the concurrent clashes between kingpost and many underground structures. Then, the engineer cannot see all the clash incidents with each kingpost and move the kingpost to avoid the clashes successfully. Since the kingpost arrangement was still an inefficient practice that was limited in the visualization aspect, this research used engineering knowledge and advanced construction technology to detect and solve the clashes between kingposts and underground structures. The methodology used engineering knowledge of kingpost arrangement to develop the system modules by using a rule-based approach. Then, these modules were developed into the system by using visual programming of Building Information Modelling (BIM). To test the system, an underground structure from building construction was selected as a case study to apply the developed system. Finally, the finding of this study could overcome human judgment by providing less interaction in the kingpost arrangement and visualization improvement of clash occurrences in the 3D model.

Simple approach to obtain ground amplification motion of surface soil deposits with a radical change of depth

2005 ◽  
Vol 42 (2) ◽  
pp. 491-498
Author(s):  
Dae-Sang Kim ◽  
Kazuo Konagai
Keyword(s):  
Seismic Design ◽  
Surface Soil ◽  
Underground Structure ◽  
Free Field ◽  
Alluvial Soil ◽  
Radical Change ◽  
Simple Approach ◽  
Clear Understanding ◽  
Underground Structures ◽  
Soil Deposits

Earthquake observations at different sites within alluvial soil deposits have demonstrated that the motion of buried underground structures closely follows that of the surrounding soil. Therefore, it is usual in a seismic design process to apply free-field ground displacements through Winkler-type soil springs to an underground structure to evaluate stress patterns induced within its structural members. Using a simplified approach, this paper provides a clear understanding of resonant horizontal ground displacement of and strain in a surface soil deposit with a radical change of depth and of where they occur.Key words: simple approach, seismic design, earthquake, resonance, underground structures.

scholarly journals Overview of Anti-Seismic Researches of Underground Structures

2018 ◽  
Vol 38 ◽  
pp. 03038
Author(s):  
Ran Liao
Keyword(s):  
Research Methods ◽  
Underground Structure ◽  
Seismic Damage ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Underground Structures ◽  
Transit System ◽  
Urban Rail ◽  
Subway System ◽  
Metro System

With the vigorous development of urban rail transit system, especially the construction of subway system, the safety of subway system draws more and more attention. The study of anti-seismic for underground structures has also become an important problem to be solved in the construction of Metro system. Based on the typical underground structure seismic damage phenomenon, this paper summarizes the seismic characteristics, research methods and design methods of underground structures to offer a guide for engineers.

Residual strength of underground structures in service

2016 ◽  
Vol 53 (6) ◽  
pp. 988-999 ◽  
Author(s):  
Taous Kamel ◽  
Ali Limam ◽  
Claire Silvani
Keyword(s):  
Stress State ◽  
Residual Strength ◽  
Underground Structure ◽  
Numerical Approach ◽  
The Finite Element Method ◽  
Underground Structures ◽  
Weathering Processes ◽  
Working Face ◽  
Metro Tunnel ◽  
Loss Of Strength

Old tunnels suffer from deterioration and it is necessary to assess their residual strength to properly organize their repair and strengthen them. The stress state of underground structures evolves over time, firstly because of the advancement of the working face during construction, then due to gradual changes in soil properties and mechanical properties of materials composing the infrastructures, such as reduction of cohesion, loss of strength and (or) stiffness, etc. These changes are caused by combined actions such as creep and (or) weathering processes as well as the appearance of cracks that induce redistribution of stresses and therefore strains. This study investigates tunnels and galleries of the Paris underground. Macromodeling based on the finite element method allows consideration of different scenarios of tunnel-lining deterioration, specifically at the extrados of the galleries or tunnels. To understand changes in the stress state, and also damage occurrence and associated redistributions (stress and strain), it is necessary to model the delayed deformations. To model the infrastructure behavior, a time-dependency approach has been chosen. This approach can quantify the damage and predict the residual strength of this type of underground structure. An elastic–viscoplastic constitutive model with strain-softening is used to reproduce the appearance of the degraded zones and their behavior. The results obtained with the numerical approach reproduce Paris metro tunnel behavior, corroborate geoendoscopy results, clarify their interpretation, and improve the management of infrastructure repairs.

scholarly journals The impact of heavy object on an underground structure when falling onto the ground surface

2021 ◽  
Vol 17 (4) ◽  
pp. 425-438
Author(s):  
Oleg V. Mkrtychev ◽  
Yury V. Novozhilov ◽  
Anton Yu. Savenkov
Keyword(s):  
Nuclear Power ◽  
Rocket Engine ◽  
Underground Structure ◽  
Ground Surface ◽  
Civil Defense ◽  
Main Task ◽  
Underground Structures ◽  
Building Collapse ◽  
Protective Structures ◽  
The Impact

At the objects of space infrastructure and at nuclear power facilities there are industrial structures, the main task of which is to protect a person, equipment or machinery from emergencies such as, for example, explosions, falling of various objects, fragments. In accordance with the requirements of the Federal Law On the Protection of the Population and Territories from Natural and Technogenic Emergencies, when calculating such structures, all types of loads corresponding to their functional purpose must be taken into account. So, for structures located in the area of a possible accident and the fall of space rockets, it is necessary to calculate for the fall of the destroyed parts of the rocket engine. For nuclear power plant facilities, such accidents occur when containers and other heavy objects fall on the ground, affecting underground structures located in the ground, and for civil defense protective structures built into the basement floors of buildings, it is necessary to consider situations in which the overlying floors of a building collapse when exposed to there is an air shock wave on them. Therefore, this problem is relevant, and in this study, a finite-element method for calculating an underground structure in a non-linear dynamic setting has been developed when a large overall object collides with the ground.

scholarly journals The Effect of Soil Reinforcement on the Stress and Strain Field Around Underground Square-Shaped Areas and its Internal Lining Efforts in Urban Areas

2018 ◽  
Vol 4 (11) ◽  
pp. 2756 ◽  
Author(s):  
Alireza Darvishpour ◽  
Asadollah Ranjbar ◽  
Amirmohammad Amiri
Keyword(s):  
Urban Areas ◽  
Underground Structure ◽  
Physical Modelling ◽  
Soil Reinforcement ◽  
Soil Parameters ◽  
Stress And Strain ◽  
Horizontal Distance ◽  
Underground Structures ◽  
Finite Element Software ◽  
Before And After

The passage of underground structures from the bottom of the structures on the ground causes a change in the stresses and strains created in the structure as well as the soil environment surrounding the tunnel due to the existence of an interaction between these two sides. In this way, the existence of the surface structure leads to a change in the strain and stress conditions around the tunnel, and in contrast, the tunnel also leads to a change in the stress and settlement around the structures. Therefore, such a reciprocal behavior is very important. In this research, with the help of Abaqus finite element software, two main possible conditions are considered: the creation of an underground structure in the presence of the superstructure, as well as the reverse state of the concept of constructing a building in the state in which the underground structure already exists. One of the subjects studied in this research is the physical modelling effect of the structure, rather than the effect of its wide load on the ground. Other parameters considered in this research are the number of story, the depth of the tunnel, the width of the tunnel, the thickness of the lining, the effect of changes in the soil parameters in the depth and the horizontal distance of the tunnel center from the building center. The results of this research are validated based on the results obtained by other researchers. According to the results obtained in this research, by the increase of the distance between the tunnel center and structure center and depending on the stiffness of the tunnel lining, significant asymmetric stresses are created in the superstructure. The construction of the structure before and after the tunnel construction can affect the unsymmetrical settlement of the structure The stress and strain created in the lining of the tunnel and the surrounding area are also different due to the amount of mobilized force in the reinforcements.

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