Seismic Response of a Base Isolated Cable-Stayed Bridge Under Near-Fault Ground Motion Excitations

2018 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Ahad Javanmardi ◽  
Zainab Ibrahim ◽  
Khaled Gheadi ◽  
Mohammed Jameel ◽  
Usman Hanif ◽  
...  

Nowadays, development of cable-stayed bridges is increasing around the world. The mitigation of seismic forces to these bridges are obligatory to prevent damages or failure of its structural members. Herein, this paper aimed to determine the near-fault ground motion effect on an existing cable-stayed bridge equipped with lead-rubber bearing. In this context, Shipshaw cable-stayed bridge is selected as the case study. The selected bridge has a span of 183.2 m composite deck and 43 m height of steel tower. 2D finite element models of the non-isolated and base isolated bridges are modelled by using SAP2000. Three different near-fault ground motions which are Tabas 1978, Cape Mendocino 1992 and Kobe 1995 were subjected to the 2D FEM models in order to determine the seismic behaviour of the bridge. The near-fault ground motions were applied to the bridge in the longitudinal direction. Nonlinear dynamic analysis was performed to determine the dynamic responses of the bridge. Comparison of dynamic response of non-isolated and base isolated bridge under three different near-fault ground motions were conducted. The results obtained from numerical analyses of the bridge showed that the isolation system lengthened the period of bridge and minimised deck displacement, base shear and base moment of the bridge. It is concluded that the isolation system significantly reduced the destructive effects of near-fault ground motions on the bridge.

2018 ◽  
Vol 15 (1) ◽  
pp. 1-14
Author(s):  
Ahad Javanmardi ◽  
Zainab Ibrahim ◽  
Khaled Gheadi ◽  
Mohammed Jameel ◽  
Usman Hanif ◽  
...  

Nowadays, development of cable-stayed bridges is increasing around the world. The mitigation of seismic forces to these bridges are obligatory to prevent damages or failure of its structural members. Herein, this paper aimed to determine the near-fault ground motion effect on an existing cablestayed bridge equipped with lead-rubber bearing. In this context, Shipshaw cable-stayed bridge is selected as the case study. The selected bridge has a span of 183.2 m composite deck and 43 m height of steel tower. 2D finite element models of the non-isolated and base isolated bridges are modelled by using SAP2000. Three different near-fault ground motions which are Tabas 1978, Cape Mendocino 1992 and Kobe 1995 were subjected to the 2D FEM models in order to determine the seismic behaviour of the bridge. The near-fault ground motions were applied to the bridge in the longitudinal direction. Nonlinear dynamic analysis was performed to determine the dynamic responses of the bridge. Comparison of dynamic response of nonisolated and base isolated bridge under three different near-fault ground motions were conducted. The results obtained from numerical analyses of the bridge showed that the isolation system lengthened the period of bridge and minimised deck displacement, base shear and base moment of the bridge. It is concluded that the isolation system significantly reduced the destructive effects of near-fault ground motions on the bridge.


2018 ◽  
Vol 15 (1) ◽  
pp. 1 ◽  
Author(s):  
AHAD JAVANMARDI ◽  
ZAINAB IBRAHIM ◽  
KHALED GHEADI ◽  
MOHAMMED JAMEEL ◽  
USMAN HANIF ◽  
...  

Nowadays, development of cable-stayed bridges is increasing around the world. The mitigation of seismic forces to these bridges are obligatory to prevent damages or failure of its structural members. Herein, this paper aimed to determine the near-fault ground motion effect on an existing cablestayed bridge equipped with lead-rubber bearing. In this context, Shipshaw cable-stayed bridge is selected as the case study. The selected bridge has a span of 183.2 m composite deck and 43 m height of steel tower. 2D finite element models of the non-isolated and base isolated bridges are modelled by using SAP2000. Three different near-fault ground motions which are Tabas 1978, Cape Mendocino 1992 and Kobe 1995 were subjected to the 2D FEM models in order to determine the seismic behaviour of the bridge. The near-fault ground motions were applied to the bridge in the longitudinal direction. Nonlinear dynamic analysis was performed to determine the dynamic responses of the bridge. Comparison of dynamic response of nonisolated and base isolated bridge under three different near-fault ground motions were conducted. The results obtained from numerical analyses of the bridge showed that the isolation system lengthened the period of bridge and minimised deck displacement, base shear and base moment of the bridge. It is concluded that the isolation system significantly reduced the destructive effects of near-fault ground motions on the bridge.


2020 ◽  
Vol 36 (3) ◽  
pp. 1485-1516
Author(s):  
Jui-Liang Lin ◽  
Wen-Hui Chen ◽  
Fu-Pei Hsiao ◽  
Yuan-Tao Weng ◽  
Wen-Cheng Shen ◽  
...  

A shaking table test of a three-story reinforced concrete (RC) building was conducted. The tested building is vertically irregular because of the first story’s elevated height and the third story’s added RC walls. In addition to far-field ground motions, near-fault ground motions were exerted on this building. A numerical model of the three-story building was constructed. Comparing with the test results indicates that the numerical model is satisfactory for simulating the seismic response of the three-story building. This validated numerical model was then further applied to look into two issues: the effective section rigidities of RC members and the effects of near-fault ground motions. The study results show the magnitude of the possible discrepancy between the actual seismic response and the estimated seismic response, when the effective section rigidities of the RC members are treated as in common practice. An incremental dynamic analysis of the three-story RC building subjected to one far-field and one near-fault ground motion, denoted as CHY047 and TCU052, respectively, was conducted. In comparison with the far-field ground motion, the near-fault ground motion is more destructive to this building. In addition, the effect of the selected near-fault ground motion (i.e. TCU052) on the building’s collapse is clearly identified.


2021 ◽  
pp. 136943322110262
Author(s):  
Xiangxiu Li ◽  
Ping Tan ◽  
Aiwen Liu ◽  
Xiaojun Li

The failure mechanism of the mega–sub isolation system under near-fault ground motions is studied in this article. 90 suites of near-fault ground motions collected from 23 earthquakes are adopted to investigate the ground motion intensity indices applicable for the mega–sub isolation system. Then, the sensitivities of the stochastic responses to the structural parameters are analyzed to determine the representative random structural parameters. Furthermore, considering the uncertainties of ground motion characteristics and structural parameters, the seismic fragility is analyzed by the response surface method in order to obtain the failure mechanism of this system under near-fault ground motions. Results show that different intensity indices have various correlation coefficients with the peak responses of the mega–sub isolation system. The correlations of acceleration-related intensity indices are the worst, whereas the correlations of displacement-related intensity indices show high linearity. The sensitivities of the structural responses are weaker to the sub-structure story stiffness but more sensitive to the sub-structure story mass and the stiffness and damping ratio of the isolation layer. The failure probability of the sub-structure is higher than that of the mega-structure under near-fault ground motion. While in the collapse state, the failure probability of the isolation layer is greater than that of the sub-structure.


2012 ◽  
Vol 594-597 ◽  
pp. 1688-1691
Author(s):  
Ming Li ◽  
Qiao Jin ◽  
Yong Liu ◽  
He Yuan ◽  
Zhe Zhe Sun

during the process of fitting or synthesizing near-fault ground motion,parameters of the equivalent velocity pulse need to be decided based on seismic records.Thus, it is a key problem that how to identify these parameters from the records.Pulse period and pulse peak velocity are important parameters in the equivalent velocity pulse models.In this study,various methods on identifying these parameters are reviewed.It is shown that all the existing methods have limitations,especially for the irregular seismic records.Finally,problems need to be further studied is pointed out.


1998 ◽  
Vol 88 (2) ◽  
pp. 428-440 ◽  
Author(s):  
Arben Pitarka ◽  
Kojiro Irikura ◽  
Tomotaka Iwata ◽  
Haruko Sekiguchi

Abstract The 17 January 1995 Hyogo-ken Nanbu earthquake is a typical example showing that the ground motions along basin-edge faults can be very destructive. In this study, we simulate the near-fault ground motion from this earthquake based on a kinematic fault model and a simplified 3D velocity structure of the Kobe area. The kinematic earthquake rupture and the wave propagation are modeled using a 3D finite-difference method (FDM). Our simulation identifies the basin-edge effect as an important factor that influenced the ground-motion amplification pattern in the Kobe area. We found that the coupling of the source directivity and basin-edge effects causes impulsive ground motions with extremely high amplitude at periods greater than 1 sec and in a narrow zone offset less than 1 km from the basin edge. The combination of these effects acted to create a fairly continuous band of amplification that extends about 30 km in an elongated zone parallel to the basin-edge boundary. In some areas, localized site effects might have been as important as the abovementioned effects, but they cannot explain the continuity of the extended east-west zone of damage.


2011 ◽  
Vol 90-93 ◽  
pp. 2633-2639
Author(s):  
Chang Hao Zhang ◽  
Wei Wang ◽  
Hu Wang ◽  
Xun Tao Wang

This paper examined the engineering characteristics of the near-fault ground motion. The four-story reinforced concrete frame was designed under Code for seismic design of building (GB50011-2010).The SAP2000 software was applied to model it, and the nonlinear time history analyses of structure were implemented. Near-fault ground motions with forward directivity and fling-step and far field ground motions were selected as seismic inputs.The results show that in terms of some structural dynamic response parameters, such as the vertex displacement, between the corner of the layer displacement, and the base shear et al., the structural responses to the ground motion with near-fault are increased by considerable magnitudes when the seismic responses of structures step into the elastic-plastic stage, compared with far-field ground motion, and the influence of damaging the mid-lower structure is significantly greater.


2021 ◽  
Author(s):  
Yafei Zhai ◽  
Liaojun Zhang ◽  
Hanyun Zhang ◽  
Tianxiao Ma ◽  
Binghui Cui

Abstract Strong earthquake cases of concrete gravity dams show that the foundation damage has an important influence on the seismic response and damage characteristics of the dam body. Compared with non-pulse ground motions, pulse-like near-fault ground motions have a wider response spectrum sensitive zone, which will cause more modes of the structure to respond, resulting in more serious damage to the structure. In order to study the real dynamic damage characteristics of concrete gravity dams under the action of near-fault ground motions, this paper takes Koyna gravity dam as the object and establishes a multi-coupling simulation model that can reasonably reflect the dynamic damage evolution process of dam concrete and foundation rock mass. A total of 12 near-fault ground motion records with three types of rupture directivity pulse, fling-step pulse and non-pulse are selected, deep research on the overall damage evolution law of concrete gravity dams. Considering the additional influence of different earthquake mechanisms, different site types and other factors on the study, the selected ground motion records are from the same seismic events (Chi-Chi), the same direction but different stations. The results show that the foundation of the concretes gravity dam often get damaged before the dam body under the action of strong earthquakes. Compared with the near-fault non-pulse ground motion, the structural damage of the gravity dam under the action of the near-fault directivity pulse ground motion is significantly increased, and causes greater damage and displacement response to the dam body. The near-fault fling-step pulse ground motion has the least impact on the dynamic response of the gravity dam structure.


10.29007/h56x ◽  
2018 ◽  
Author(s):  
Ankita Shah ◽  
Vijay R. Panchal

In this study, the performance of elevated steel water tank with TFPS isolation under near fault ground motion is evaluated. Mathematical model of storage tank is distinct with four degree of freedom model includes tower structure, sloshing mass, isolation system and impulsive mass. TFPS provided at foundation level of tower structure. Performance of TFPS is compared with FPS using SAP 2000.


2020 ◽  
Vol 3 (2) ◽  
pp. 841-849
Author(s):  
Esengul Cavdar ◽  
Gokhan Ozdemir ◽  
Ozkan Kale

Ground motions recorded at near fault zones ensures rich low frequency contents, and high velocity pulse signals which may result in large shear force and displacement demands in structural elements. During the recording of these seismic events by accelerometers, low-frequency noise may sometimes accompany the signal. Thus, extracting this noise from recorded acceleration data is a crucial step of post-processing performed prior to use of acceleration time series in structural analyses for both design or assessment purpose. The objective of this study is to assess the effect of high-pass filtering on the intensity measures of ground motions. A set of near fault ground motions that comprises both pulse-like and non-pulse like characteristics were selected and they were subjected to filtering for various cutting frequency contents. As a function of filtering, variation in several intensity measures of filtered ground motions namely, PGD, PGV, PGA, PGV/PGA and significant duration were analyzed. It is revealed that changing the cutting frequency of high pass filtering considerably changes the intensity measures of ground motion records.


Sign in / Sign up

Export Citation Format

Share Document