Response of Transmission Lines under Three-Dimensional Seismic Excitations

2012 ◽  
Vol 166-169 ◽  
pp. 2259-2264
Author(s):  
Li Tian ◽  
Hong Nan Li ◽  
Wen Ming Wang
Keyword(s):  
Transmission Line ◽  
Ground Motion ◽  
Transmission Lines ◽  
Three Dimensional ◽  
Time History ◽  
Maximum Response ◽  
Nonlinear Time History Analysis ◽  
Seismic Excitations ◽  
Practical Engineering ◽  
Nonlinear Time History

The behavior of transmission line under three-dimensional seismic excitations is studied by numerical simulation. According to a practical engineering, the transmission towers are modeled by frame elements and the transmission lines are modeled by cable element account for the nonlinearity of the cable. The effects of single-dimensional, two-dimensional and three-dimensional ground motions on the responses of transmission line are investigated using nonlinear time history analysis method, respectively. The results indicate that the longitudinal maximum response of transmission lines can be obtained considering longitudinal ground motion excitation only. The transverse maximum response of transmission lines can be obtained considering transverse ground motion excitation only. Neglecting multiple nature of ground motion in analysis will significantly underestimate the vertical responses of the transmission lines. To obtain an accurate seismic response of transmission lines, three-dimensional ground motion inputs are required.

Seismic Performance Analysis of the Special-Shaped Frame Column Structure on Multi-Dimensional Seismic

2011 ◽  
Vol 90-93 ◽  
pp. 1644-1648
Author(s):  
Dong Qiang Xu ◽  
Mei Mei He
Keyword(s):  
Ground Motion ◽  
Time History ◽  
Regular Structure ◽  
Frame Structure ◽  
Nonlinear Time History Analysis ◽  
Weak Links ◽  
Column Structure ◽  
Structure Torsion ◽  
Torsional Component ◽  
Nonlinear Time History

The article considers the two horizontal components of ground motion and torsional component, to do nonlinear time history analysis both on regular and irregular shaped column frame structure models. The results show that torsional component of ground motion haves some impact on torsion reaction of structures, stiffness of irregular shaped column frame structure is uneven, and angle of columns are greater than that of the regular structure; torsion haves some impact on the torque of structure, the torque increases of corner columns is maximum, so corner columns are weak links in shaped column structure, considered fully during the seismic design.

A superelastic protective technique for mitigating the effects of vertical and horizontal seismic excitations on highway bridges

2016 ◽  
Vol 28 (12) ◽  
pp. 1533-1552 ◽  
Author(s):  
Hadi Aryan ◽  
Mehdi Ghassemieh
Keyword(s):  
Three Dimensional ◽  
Vertical Component ◽  
Time History ◽  
Highway Bridges ◽  
Three Dimensional Model ◽  
Seismic Excitations ◽  
Innovative System ◽  
Bridge Responses ◽  
Nonlinear Time History ◽  
New System

Vertical component of seismic excitations tremendously affects the performance of bridges during the earthquakes. Several conducted studies identified the lack of engineering attention to the vertical seismic excitation as the main reason of various considerable bridge damages during the past earthquakes. Thus, in this article, an innovative system with superelastic properties is proposed for retrofitting and also new design of the bridges which can simultaneously mitigate the effects of vertical and horizontal seismic excitations. In order to investigate the efficiency of the new system, an evaluation is performed through many nonlinear time history analyses on a three-dimensional model of a detailed multi-span simply supported bridge using a suite of representative ground motions of the bridge region. The analyses are conducted separately on the pertinent issues that affect the performance of the new proposed system. As a part of the study, to identify the sensitivity of the new system and evaluate the overall seismic performance, several assessment parameters are utilized. The results show that the proposed system is efficient for reducing bridge responses as well as improving nonlinear performance of the columns during vertical and horizontal seismic excitations.

scholarly journals Nonlinear Seismic Behavior of Different Boundary Conditions of Transmission Line Systems under Earthquake Loading

2016 ◽  
Vol 2016 ◽  
pp. 1-9
Author(s):  
Li Tian ◽  
Xia Gai
Keyword(s):  
Boundary Conditions ◽  
Transmission Line ◽  
Transmission Lines ◽  
Seismic Analysis ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Earthquake Loading ◽  
Transmission Tower ◽  
Line System ◽  
Different Boundary Conditions

Nonlinear seismic behaviors of different boundary conditions of transmission line system under earthquake loading are investigated in this paper. The transmission lines are modeled by cable element accounting for the nonlinearity of the cable. For the suspension type, three towers and two span lines with spring model (Model 1) and three towers and four span lines’ model (Model 2) are established, respectively. For the tension type, three towers and two span lines’ model (Model 3) and three towers and four span lines’ model (Model 4) are created, respectively. The frequencies of the transmission towers and transmission lines of the suspension type and tension type are calculated, respectively. The responses of the suspension type and tension type are investigated using nonlinear time history analysis method, respectively. The results show that the responses of the transmission tower and transmission line of the two models of the suspension type are slightly different. However, the responses of transmission tower and transmission line of the two models of the tension type are significantly different. Therefore, in order to obtain accurate results, a reasonable model should be considered. The results could provide a reference for the seismic analysis of the transmission tower-line system.

Seismic Reliability Analysis of Structural Systems

2009 ◽  
Author(s):  
Paata Rekvava
Keyword(s):  
Three Dimensional ◽  
Design Procedure ◽  
Time History ◽  
Reliability Function ◽  
Nonlinear Time History Analysis ◽  
Structural Systems ◽  
Rc Buildings ◽  
Seismic Reliability ◽  
Performance Based Seismic Design ◽  
Nonlinear Time History

A method is presented for the evaluation of the seismic reliability function of realistic structural systems. The method is based on a preliminary simulation involving three-dimensional nonlinear time history analysis of the soil-interface-building system. The design procedure is performed to establish the probabilistic characterization of the demands on the structure, followed by the solution of system reliability problem with correlated demands and capacities. The Structural behavior is evaluated by means of the methodology of Performance-Based Seismic Design (PBSD). This study has taken into account the stochastic nature of the spatial ground motion in Tbilisi region. The method is demonstrated with an application to a 3D RC Buildings subjected to seismic excitation for the specified hazard at the site. The developed method and obtained results can be used in seismic risk study for new buildings of examined type under design, as well as for existing RC buildings of old generation for future seismic activity.

Mitigation of Vertical and Horizontal Seismic Excitations on Bridges Utilizing Shape Memory Alloy System

2013 ◽  
Vol 831 ◽  
pp. 90-94 ◽  
Author(s):  
H. Aryan ◽  
M. Ghassemieh
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Three Dimensional ◽  
Time History ◽  
Alloy System ◽  
Practical Method ◽  
Nonlinear Time History Analysis ◽  
Vertical Acceleration ◽  
Three Dimensional Model ◽  
Seismic Excitations

Vertical seismic excitation has a tremendous effect on bridges and many researchers have pointed out bridges damages occurred during the past significant earthquakes which were direct results of ignoring vertical acceleration of ground motions. Many studies have emphasized the importance of extending practical methods to reduce effects of vertical acceleration of earthquakes besides effects of horizontal accelerations; but no practical method has proposed up to now. In this article, an innovative shape memory alloy system is proposed for bridges that can simultaneously controls effects of vertical and horizontal seismic excitations on bridge and reduce them. To evaluate the effectiveness of the shape memory alloy system, a nonlinear time history analysis is conducted on a detailed three-dimensional model of a multi-span simply supported bridge using a representative ground motion. The results show that the proposed new system is very effective for reducing effects of vertical and horizontal seismic excitations on bridges.

scholarly journals Effect of Ground Motion Directionality on Fragility Characteristics of a Highway Bridge

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Swagata Banerjee Basu ◽  
Masanobu Shinozuka
Keyword(s):  
Ground Motion ◽  
Dimensional Space ◽  
Fragility Curves ◽  
Time History ◽  
Transportation Systems ◽  
Nonlinear Time History Analysis ◽  
Response Analysis ◽  
Seismic Fault ◽  
Principal Axes ◽  
Nonlinear Time History

It is difficult to incorporate multidimensional effect of the ground motion in the design and response analysis of structures. The motion trajectory in the corresponding multi-dimensional space results in time variant principal axes of the motion and defies any meaningful definition of directionality of the motion. However, it is desirable to consider the directionality of the ground motion in assessing the seismic damageability of bridges which are one of the most vulnerable components of highway transportation systems. This paper presents a practice-oriented procedure in which the structure can be designed to ensure the safety under single or a pair of independent orthogonal ground motions traveling horizontally with an arbitrary direction to structural axis. This procedure uses nonlinear time history analysis and accounts for the effect of directionality in the form of fragility curves. The word directionality used here is different from “directivity” used in seismology to mean a specific characteristic of seismic fault movement.

Analysis of Pounding Response for Simply Supported Skew Girder Bridge under Earthquake

2011 ◽  
Vol 90-93 ◽  
pp. 1234-1238 ◽  
Author(s):  
Qing Kai Sun ◽  
Xing Jun Qi ◽  
Yi Liu
Keyword(s):  
Three Dimensional ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Expansion Joint ◽  
Simply Supported ◽  
Side Beam ◽  
Joint Width ◽  
Girder Bridge ◽  
Collision Force ◽  
Nonlinear Time History

Under the earthquake, pounding between the beam and the bridge abutment causes great damages to skew girder bridge, and current study on pounding response is still less as the collision effect is complex. In order to study the displacement and collision force under Elcentro and Tianjin ground motion, a three-dimensional finite element computational model for seismic pounding of a 16m simply supported skew girder bridge was established and nonlinear time-history analysis was carried out with pounding element designed to simulate the pounding effect between beam and abutment. The results show that the displacement of side beam is more than that of middle beam in simply supported skew girder bridge. The maximum collision force of the side beam is more than that of middle beam, and the beam pounds the abutment several times. Appropriate expansion joint width should be set according to the displacement of the side beam when the expansion joint designed.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

Probabilistic Peak Displacement Analysis of Bridge Structures with P-Δ Effect

2013 ◽  
Vol 405-408 ◽  
pp. 1674-1677
Author(s):  
Bo Yu ◽  
Di Liu ◽  
Lu Feng Yang
Keyword(s):  
Time History ◽  
Dynamic Responses ◽  
Nonlinear Time History Analysis ◽  
Bridge Structure ◽  
Vibration Period ◽  
Peak Displacement ◽  
Sdof System ◽  
Bridge Structures ◽  
Performance Based Seismic Design ◽  
Nonlinear Time History

Peak displacement is one of the most important parameters for the performance based seismic design of bridge structure, while the peak displacement is often significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the statistics of peak displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single degree of freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the mean and dispersion of peak displacement of bridge structures, especially if the normalized yield strength and the natural vibration period are small.

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