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 Numerical assessment of vertical ground motion effects on highway bridges

2020 ◽  
Vol 47 (7) ◽  
pp. 790-800 ◽  
Author(s):  
Hadi Aryan ◽  
Mehdi Ghassemieh
Keyword(s):  
Ground Motion ◽  
Numerical Study ◽  
Three Dimensional ◽  
Vertical Component ◽  
Time History ◽  
Highway Bridges ◽  
Vertical Excitation ◽  
Vertical Ground Motion ◽  
Field Evidence ◽  
Vertical Ground

Field evidence of recent earthquakes shows serious bridge damages due to the direct compression or tension in the columns and some flexural and shear failures caused by the variation in axial force of the columns. These damages could not be produced solely by the horizontal seismic excitations; the vertical component of the earthquake is involved. This paper presents a numerical study highlighting the presence of vertical seismic excitation. Nonlinear time history analyses are conducted on detailed three-dimensional models of multi-span simply supported and multi-span continuous bridges using a suite of representative ground motions. The results showed the significant influence of vertical excitation on the bridge responses. Therefore, it is imperative to include more efficient criteria to upgrade the design codes and extend practical techniques that consider and cope with the structural effects of vertical ground motion along with the horizontal excitations.

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.

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 Optimum Design of TMD System for Tall Buildings

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Ahmed Abdelraheem Farghaly ◽  
Mahmoud Salem Ahmed
Keyword(s):  
Three Dimensional ◽  
Design Procedure ◽  
Structural Response ◽  
Time History ◽  
Tall Buildings ◽  
Three Dimensional Model ◽  
Seismic Excitations ◽  
History Analysis ◽  
Mass Damper ◽  
Dynamic Excitations

As tall buildings keep becoming taller, they become more susceptible to dynamic excitations such as wind and seismic excitations. In this paper, design procedure and some current applications of tuned mass damper (TMD) are discussed. A symmetrical moment resistance frame (MRF) twenty storey three-dimensional model were modeled in SAP2000 and a TMD was placed on its top and through it to study its effects on the structural response due to seismic excitations and using time history analysis with and without the TMD. The study indicates that the response of structure such as storey displacements and shear force of columns can be dramatically reduced by using TMD (groups of TMDs) devices especially with a specific arrangement in the model. The study illustrates the group of four TMDs distributed on the plan (interior) which can be effective as R.C. core shear wall.

CONTROL OF ERRORS USING A SIMPLIFIED CLINICAL SETUP FOR MOTION ANALYSIS: ERRORS DUE TO CALIBRATION AND THREE-DIMENSIONAL RECONSTRUCTION

2005 ◽  
Vol 05 (04) ◽  
pp. 491-505 ◽  
Author(s):  
ERIC BERTHONNAUD ◽  
JOANNÈS DIMNET
Keyword(s):  
Motion Analysis ◽  
Center Of Mass ◽  
Force Plate ◽  
Three Dimensional ◽  
Vertical Component ◽  
Calibration Procedure ◽  
Human Movements ◽  
Dimensional Reconstruction ◽  
Analysis Errors ◽  
New System

Different systems of motion analysis have been described. They usually associate several cameras with a force platform. They can analyze very sophisticated human movements. They are, however, expensive and require significant technical formation from users. A new system is proposed for simple and standard clinical applications. It uses only two cameras and a coupled force plate delivering only the vertical component of the patient weight and the location of his center of mass. It is inexpensive, simple to use and delivers accurate results. This is obtained through a strict experimental protocol, and a new method of data treatment which allows the control of errors at each step of the successive calculations. This paper describes the new system, the new calibration procedure and the control of errors.

A Transfer Function Analysis of a Geomagnetic Depth Sounding-Profile across Central British Columbia

1973 ◽  
Vol 10 (7) ◽  
pp. 1089-1098 ◽  
Author(s):  
H. Dragert
Keyword(s):  
British Columbia ◽  
Transfer Functions ◽  
Function Analysis ◽  
Three Dimensional ◽  
Vertical Component ◽  
Rocky Mountain ◽  
Three Dimensional Model ◽  
Transfer Function Analysis ◽  
Single Station ◽  
Depth Sounding

Time variations of the geomagnetic field observed across British Columbia at a mean latitude of 54 °N are analyzed using 'single-station' and 'paired-station' optimum transfer functions. The frequency and spatial dependence of both coastal and inland geomagnetic anomalies are estimated with the following results. (1) The normal coast effect is strongly perturbed by lateral conductivity inhomogeneities both north and south of the profile. (2) A simple, single NW–SE striking conductivity contrast between the Cordillera and plains cannot account for the total geomagnetic anomaly in the area of the Rocky Mountain Trench; a three-dimensional model is required, incorporating (i) a lateral inhomogeneity striking east–west and located to the south of the profile, (ii) the effect of induction by the vertical component of source or secondary fields.

scholarly journals Driving Direction Displacement Analysis of Asphalt Pavement under Fluctuating Load

2020 ◽  
Vol 165 ◽  
pp. 03043
Author(s):  
Gao Jianhong ◽  
Xu Youjun ◽  
Yang Shengchun
Keyword(s):  
Dynamic Load ◽  
Transient Analysis ◽  
Asphalt Pavement ◽  
Three Dimensional ◽  
Time History ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Finite Element Software ◽  
Half Wave ◽  
Peak Value

The finite element software ANSYS is used to build the asphalt pavement three-dimensional model and to carry through transient analysis. The z-direction displacement time history curves of asphalt pavement under half wave sine load are obtained. The curves reveal that the dynamic load influence on pavement structure Z-direction displacement is complex; The z-direction displacement always reaches its peak value when the load reaches this point, and it decreases rapidly to zero after the load leaves; The Z-direction displacement influence of dynamic load increases with the increase of depth. These conclusions can provide a reference for asphalt pavement under half wave sinusoidal dynamic load.

A Comparative Study on Dynamic Wheel Loads of Multi-Axle Vehicle and Bridge Responses

2001 ◽  
Author(s):  
Chul Woo Kim ◽  
Mitsuo Kawatani
Keyword(s):  
Analytical Procedure ◽  
Three Dimensional ◽  
Highway Bridges ◽  
Dynamic Responses ◽  
Dynamic Factor ◽  
Wheel Load ◽  
Coupling Vibration ◽  
Moving Vehicle ◽  
Speed Parameter ◽  
Bridge Responses

Abstract To investigate relations between dynamic wheel loads of multi-axle vehicles on highway bridges and dynamic responses of bridge due to the vehicular loading, a three-dimensional dynamic analysis is carried out. Simultaneous differential equations for a coupling vibration of bridge and moving vehicle including roadway roughness are derived by means of modal analysis. The analytical wheel loads of vehicle model and responses of bridges are compared with experimental ones, to verify a validity of presented analytical procedure. Parametric investigations show that there exists resemblance between bounce motion of vehicle and bridge response. It can also be seen that the RMS based dynamic factor of dynamic wheel load can give an important information to predict the variation of impact factor of bridge due to speed condition as well as speed parameter.

Identification of Vehicle-Bridge Interactive Forces From Measured Bridge Responses: Theoretical Studies

1995 ◽  
Author(s):  
S. S. Law ◽  
Tommy H. T. Chan ◽  
Q. H. Zeng
Keyword(s):  
Time History ◽  
Bending Moment ◽  
Highway Bridges ◽  
Interaction Force ◽  
Superposition Method ◽  
Vibration Data ◽  
Moving Force ◽  
Modal Superposition Method ◽  
History Of ◽  
Bridge Responses

Abstract Information of the vehicle-bridge interaction force is an important parameter in the design and evaluation of highway bridges. However it is difficult to directly measure or accurately calculate the force which is a moving force. The objective of this paper is to explore the theory of force identification based on the response of the structure to acquire a time history of the moving force. The force will be identified in time domain using a modal superposition method. A moving force on a simply supported beam is simulated, and the computational results show that the method is noise sensitive, and yet acceptable results can be obtained by combining the use of vibration data of the bending moment and acceleration measurements.

Dynamic inelastic analyses of a bridge structure

1981 ◽  
Vol 71 (2) ◽  
pp. 517-530
Author(s):  
A. G. Gillies ◽  
R. Shepherd
Keyword(s):  
Equations Of Motion ◽  
Resistance Mechanism ◽  
Three Dimensional ◽  
Time History ◽  
Bridge Structure ◽  
Three Dimensional Model ◽  
Earthquake Excitation ◽  
Plastic Yield ◽  
Analysis Technique ◽  
Bridge Structures

abstract The necessity for framed structures to be capable of dissipating significant amounts of energy inelastically under severe earthquake excitation is generally acknowledged. Bridge structures differ from buildings in their seismic lateral resistance mechanism in so far as they generally possess a small number of clearly identifiable potential zones in which plastic yield can occur and consequently tend to be amenable to postelastic studies. This paper presents the application of an analysis technique in which the response time history of a bridge structure, treated as a three-dimensional frame, is determined by direct integration of the equations of motion with allowances incorporated for inelastic member behavior. Aspects studied include the differences in responses predicted using a nonlinear three-dimensional model rather than a planar frame idealization and the effect of unequal span lengths or torsional vibrations.

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