scholarly journals Analysis on the Influence of Increasing Seismic Fortification Intensity on Seismic Performance of Underground Station

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ying Zeng ◽  
Shiguang Xu ◽  
Shiqian Yin
Keyword(s):  
Ground Motion ◽  
Seismic Performance ◽  
Time History ◽  
Time History Analysis ◽  
Structural Deformation ◽  
Equivalent Linearization ◽  
History Analysis ◽  
Underground Station ◽  
The Impact ◽  
Station Structure

China Earthquake Parameter Zoning (2016) has increased the seismic fortification intensity in Chengdu from VII to VIII. It is necessary to conduct in-depth discussion on the impact of the seismic performance of the built underground station structure. In this paper, a stratum-structure finite element model is established with a Chengdu subway station as an example. The model boundary adopts viscoelastic boundary, and the ground motion is input in the form of equivalent nodal force. The equivalent linearization method is used to consider the nonlinearity of soil materials. The time-history analysis of seismic fortification intensity of VII and VIII degrees is carried out, respectively. By comparing the calculation results of the two seismic fortification intensity ground motion conditions, it is concluded that the connection between the side wall and the floor is the weakest position of the station structure under the action of the earthquake; the seismic fortification intensity is increased from VII to VIII to the internal force of the structure. It has a relatively large impact, especially the most obvious impact on the bending moment. The results of the verification of the seismic time-history analysis show that the increase of fortification intensity will have a more obvious impact on the structural deformation, and the structural design of the station can meet the safety performance requirements of VII and VIII degrees of seismic fortification. The research has certain reference significance for the seismic safety evaluation of the built underground station structure in Chengdu area.

scholarly journals Seismic Performance Evaluation of a Reinforced Concrete Arch Bridge

2017 ◽  
Vol 12 (1) ◽  
pp. 120-126
Author(s):  
Jeena Dangol ◽  
Rajan Suwal
Keyword(s):  
Reinforced Concrete ◽  
Ground Motion ◽  
Seismic Performance ◽  
Axial Force ◽  
Time History ◽  
Time History Analysis ◽  
Longitudinal Displacement ◽  
Arch Bridge ◽  
History Analysis ◽  
Force Variation

The entire Himalayan belt including Nepal area, because of its active tectonic movement, is seismically active causing high risk of earthquake in this region. It is important to evaluate the seismic performance of the structures including bridges to identify to what extent they would survive during earthquake. A reinforced concrete two hinged arch bridge located in Chobhar, Nepal has been selected for the research purpose. This paper presents the determination of seismic performance of a reinforced concrete arch bridge under different ground motions. The seismic input was taken as five different earthquake ground motion histories having different V/H peak ground acceleration ratio for time history analysis. Displacement capacity of the bridge was determined from pushover analysis. Time history analysis was conducted in two different steps: first only horizontal acceleration was applied and next vertical acceleration was applied in addition to horizontal ground motion. Comparisons were made between the responses of the bridge for these two cases. It was found that inclusion of vertical component of ground motion has negligible effect in variation of longitudinal displacement. However, there was remarkable effect in axial force variation. Significant effect in axial force variation in arch rib was observed as V/H ratio increased although the effect in longitudinal displacement with increase in V/H ratio was negligible. Moment demand also increased due to high axial force variation because of vertical ground motion.Journal of the Institute of Engineering, 2016, 12(1): 120-126

Seismic Assessment of RC Arch Bridge: A Case of 2015 Gorkha Earthquake

2019 ◽  
Vol 15 (1) ◽  
pp. 47-53
Author(s):  
Prakash Gaire ◽  
Ma Hongwang
Keyword(s):  
Ground Motion ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Gorkha Earthquake ◽  
Arch Bridge ◽  
History Analysis ◽  
2015 Gorkha Earthquake ◽  
Seismic Force ◽  
The Impact

Nepal Himalayas is one of the most seismic vulnerable zones. The active tectonic action impels the assessment of structures in possible seismic hazards including the bridge structures. This paper presents the impact of the 2015 Gorkha earthquake on the existing reinforced concrete arch bridge at Chobhar, Nepal. A three-dimensional model of the bridge is constructed using Open Sees platform. Nonlinear pushover analysis was performed to find the displacement capacity of the bridge. Ground motion from the main shock of the 2015 Gorkha earthquake is used in this study. Nonlinear time history analysis is performed with three orthogonal ground motions applied in the transverse, longitudinal and vertical direction of the bridge. The study investigates the safety of the bridge scaling up the ground motion to potential PGA in Nepal Himalayas; the result demonstrated the necessity of retrofit to ensure the safety level. Moreover, the horizontal seismic force obtained from the time history analysis is compared with the force obtained from the design code of the bridge. Also, the design force as per the present code (revised code) is presented.

Passive Control of Seismic Response of Piping Systems

2005 ◽  
Vol 128 (3) ◽  
pp. 364-369 ◽  
Author(s):  
Y. M. Parulekar ◽  
G. R. Reddy ◽  
K. K. Vaze ◽  
K. Muthumani
Keyword(s):  
Passive Control ◽  
Response Spectrum ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Equivalent Linearization ◽  
Piping System ◽  
Equivalent Damping ◽  
History Analysis ◽  
Piping Systems

Passive energy dissipating devices, such as elastoplastic dampers (EPDs) can be used for eliminating snubbers and reducing the response of piping systems subjected to seismic loads. Cantilever and three-dimensional piping systems were tested with and without EPD on shaker table. Using a finite element model of the piping systems, linear and nonlinear time-history analysis is carried out using Newmark’s time integration technique. Equivalent linearization technique, such as Caughey method, is used to evaluate the equivalent damping of the piping systems supported on elastoplastic damper. An iterative response spectrum method is used for evaluating response of the piping system using this equivalent damping. The analytical maximum response displacement obtained at the elastoplastic damper support for the two piping systems is compared with experimental values and time history analysis values. It has been concluded that the iterative response spectrum technique using Caughey equivalent damping is simple and results in reasonably acceptable response of the piping systems supported on EPD.

Seismic Vulnerability Analysis of Mid-Story Isolation and Reduction Structures Based Stochastic Vibration

2011 ◽  
Vol 243-249 ◽  
pp. 3988-3991 ◽  
Author(s):  
Pei Ju Chang ◽  
Jian Zhu
Keyword(s):  
Ground Motion ◽  
Random Sample ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Response Spectrum ◽  
Time History ◽  
Time History Analysis ◽  
Good Effect ◽  
History Analysis ◽  
Reduction Effect

This study focus on derivation of such fragility curves using classic mid-story isolation and reduction structures (MIRS) in China metropolis. A set of stochastic earthquake waves compatible with the response spectrum of China seismic code selected to represent the variability in ground motion. Dynamic inelastic time history analysis was used to analyze the random sample of structures. The result reveal that good effect for superstructure and reduction effect for substructure of MIRS is favorable and obvious under major earthquake, Weak position of MIRS was be pointed out and fragility curves of typical MIRS of China was obtained finally.

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