Ambient and forced-vibration tests of the Beauharnois suspension bridge

2000 ◽  
Vol 27 (6) ◽  
pp. 1162-1172 ◽  
Author(s):  
P Paultre ◽  
J Proulx ◽  
T Bégin
Keyword(s):  
Forced Vibration ◽  
Dynamic Properties ◽  
Suspension Bridge ◽  
Rehabilitation Program ◽  
Mode Shapes ◽  
Experimental Program ◽  
Dynamic Amplification Factor ◽  
Dynamic Amplification ◽  
Vibration Tests ◽  
Steel Trusses

Ambient and forced vibration tests were carried out on the Beauharnois Bridge, a unique, 177-m combined suspension and cable-stayed structure near Montreal. A rehabilitation program was completed on the bridge during which the deck was completely rebuilt with an orthotropic slab on two steel trusses. The rehabilitation program also included the addition of two pairs of stay cables on both towers, creating a hybrid suspension system. The paper presents a series of dynamic tests performed to evaluate the dynamic properties and the dynamic amplification factor (DAF) for the rehabilitated bridge. The experimental program involved the measurement of vertical, transverse, and longitudinal acceleration responses of the deck and tower under ambient and controlled traffic loads. Displacement, strain, and integrated acceleration DAFs were computed under different loading conditions. Modal properties were evaluated and used to correlate a three-dimensional finite element model for the bridge, including nonlinear cable behaviour. The paper discusses the experimental setup and the techniques used to evaluate vibration frequencies, mode shapes, and the DAF. Correlation of numerical dynamic properties and experimental results is also presented. Key words: cable-stayed bridge, dynamic amplification, dynamic testing, numerical correlation, modal analysis, suspension bridge.

scholarly journals Evaluation of Stiffness and Dynamic Properties of a Mine Shaft Steelwork Structure through In Situ Tests and Numerical Simulations

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 664
Author(s):  
Jacek Jakubowski ◽  
Przemysław Fiołek
Keyword(s):  
Numerical Simulations ◽  
Dynamic Properties ◽  
Vertical Motion ◽  
Load Test ◽  
Mode Shapes ◽  
Dynamic Amplification Factor ◽  
In Situ Tests ◽  
Mine Shaft ◽  
Numerical Investigations

A mine shaft steelwork is a three-dimensional frame that directs the vertical motion of conveyances in mine shafts. Here, we conduct field and numerical investigations on the stiffness and dynamic properties of these structures. Based on the design documentation of the shaft, materials data, and site inspection, the steelwork’s finite element model, featuring material and geometric non-linearities, was developed in Abaqus. Static load tests of steelwork were carried out in an underground mine shaft. Numerical simulations reflecting the load test conditions showed strong agreement with the in situ measurements. The validated numerical model was used to assess the dynamic characteristics of the structure. Dynamic linear and non-linear analyses delivered the natural frequencies, mode shapes, and structural response to dynamic loads. The current practices and regulations regarding shaft steelwork design and maintenance do not account for the stiffness of guide-to-bunton connections and disregard dynamic factors. Our experimental and numerical investigations show that these connections provide considerable stiffness, which leads to the redistribution and reduction in bending moments and increased stiffness of the construction. The results also show a high dynamic amplification factor. The omission of these features implicates an incorrect assessment of the design loads and can lead to over- or under-sized structures and ultimately to shortened design working life or failure.

DYNAMIC AMPLIFICATION OF BRIDGE/VEHICLE INTERACTION: A PARAMETRIC STUDY FOR A SKEWED BRIDGE

2003 ◽  
Vol 03 (01) ◽  
pp. 71-90 ◽  
Author(s):  
HUAN ZENG ◽  
CHARLES W. BERT
Keyword(s):  
Parametric Study ◽  
Superposition Principle ◽  
Ritz Method ◽  
Mode Shapes ◽  
Skew Angle ◽  
Dynamic Amplification Factor ◽  
Traffic Condition ◽  
Analytical Technique ◽  
Contact Points ◽  
Dynamic Amplification

The dynamic amplification of a bridge response due to moving vehicles has been the subject of numerous research efforts. The efforts indicate a common difficulty in treating the dynamic interaction. This paper presents a semi-analytical technique to solve the bridge/vehicle interaction problem. A skew bridge, idealized as a discretely stiffened thin isotropic plate, is considered. The natural frequencies and mode shapes of the bridge are computed by a pb-2 Rayleigh–Ritz method. The mode superposition principle is then applied. The dynamic response of the bridge to moving vehicle excitation is expressed in terms of mode shapes and normal coordinates. A three-dimensional three-axle vehicle model is developed and consists of 11 independent degrees of freedom. The bridge and the vehicle are treated as two separate systems connected only at the time-varying contact points. An iteration technique is used to deal with the true coupling between the bridge and the vehicle and to satisfy the compatibility of forces and displacements at the contact points. At last, a parametric study is conducted to investigate the dynamic amplification factor. The influences of vehicle type, axle spacing, traffic condition, span length, and skew angle are examined.

Dynamic Characteristics of Tsing Ma Suspension Bridge

1996 ◽  
Vol 1541 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Siu Kui Au ◽  
Neil Mickleborough ◽  
Paul N. Roschke
Keyword(s):  
Analytical Solutions ◽  
Bridge Deck ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Suspension Bridge ◽  
Mode Shapes ◽  
Out Of Plane ◽  
Quantitative Results ◽  
Suspension Cable ◽  
Bending Modes

Numerical simulation was carried out to determine the dynamic properties of the Tsing Ma Suspension Bridge. Both the structure as a whole and individual subcomponents were modeled. Classical analytical solutions for simplified models from the available literature were compared with the results obtained from a finite-element code. Quantitative results for static deflection, natural frequencies, and mode shapes were compared with analytical solutions from linear theory. Out-of-plane modes were shown to be dominant. For in-plane antisymmetric and symmetric bending modes, in which the suspension cable and bridge deck vibrate in the same direction, the natural frequency of the main span of the bridge is determined to be approximately equal to the square root of the sum of the squares of the frequencies of the cable and bridge deck.

Forced and Ambient Vibration Tests and Vibration Monitoring of Hakucho Suspension Bridge

2000 ◽  
Vol 1696 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Yozo Fujino ◽  
Masato Abe ◽  
Hajime Shibuya ◽  
Masato Yanagihara ◽  
Masashi Sato ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Three Dimensional ◽  
Suspension Bridge ◽  
Element Model ◽  
Vibration Monitoring ◽  
Ambient Vibration ◽  
Mode Shapes ◽  
Ambient Vibration Tests ◽  
Bending Mode ◽  
Vibration Tests

Forced and ambient dynamic tests of the Hakucho Bridge were carried out to study the dynamic characteristics of this suspension bridge. Dense-array measurement was employed in order to capture not only natural frequencies and damping, but also the mode shapes of the bridge. The natural frequencies and mode shapes obtained from the forced and ambient vibration tests agreed well with those calculated by a three-dimensional finite element model. A new method that combines the random decrement method with the Ibrahim time domain method is proposed to systematically identify the natural frequencies, damping, and mode shapes. This method is successfully applied to ambient vibration data. It is shown that the natural frequency of the first vertical bending mode decreases noticeably as the wind speed increases. It is also shown that the shape of the first vertical bending mode changes slightly near the towers, depending on the wind velocity; this finding indicates that the change may be associated with friction in the bearings at the towers. Finally, application of the Global Positioning System to measure static displacement of the girder is explained.

scholarly journals Evaluation of the Increased Dynamic Effects on the Highway Bridge Superstructure

2018 ◽  
Vol 13 (3) ◽  
Author(s):  
Ilze Paeglite ◽  
Juris Smirnovs ◽  
Ainars Paeglitis
Keyword(s):  
Amplification Factor ◽  
Dynamic Properties ◽  
Concrete Slab ◽  
Damping Ratio ◽  
Dynamic Amplification Factor ◽  
Reinforced Concrete Slab ◽  
Girder Bridges ◽  
Bridge Superstructure ◽  
High Dynamic ◽  
Dynamic Amplification

Dynamic properties of the bridge superstructure vary depending on many characteristics of the bridge and the loading conditions. In this paper, maximum Dynamic Amplification Factor was calculated for six different types of typical pre-stressed concrete beam bridges. It showed that each type of bridge with similar loading has a different range of Dynamic Amplification Factor. At the same time, every recently built bridge has different geometry and design load. Hence, it is difficult to determine a characteristic value of Dynamic Amplification Factor for the similar type of structures. By using fullscale dynamic and static bridge tests, it is possible to determine the necessary characteristics which show possibly high Dynamic Amplification Factor. This factor indicates if it is necessary to make a full-scale bridge dynamic analysis. It was found that those characteristics are natural frequency (first mode), damping ratio, relative deflection, and span and depth ratio. Obtained results from tests show a range of values for each of the characteristic. These ranges were analysed for reinforced concrete slab and pre-stressed concrete slab, and girder bridges.

Forced Vibration Testing and Finite Element Modeling of a Nine-Story Reinforced Concrete Flat Plate-Wall Building

2015 ◽  
Vol 31 (2) ◽  
pp. 1069-1081 ◽  
Author(s):  
Ozan Cem Celik ◽  
Haluk Sucuoğlu ◽  
Ugurhan Akyuz
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Flat Plate ◽  
Forced Vibration ◽  
Structural Model ◽  
Dynamic Properties ◽  
Mode Shapes ◽  
Structural System ◽  
Vibration Testing ◽  
Forced Vibration Testing

Tunnel form buildings, owing to their higher construction speed and quality, lower cost, and superior earthquake resistance over that of conventional reinforced concrete buildings, have been widely used for mass housing, urban renewal, and post-earthquake reconstruction projects all over the world as well as in Turkey. However, there have been few dynamic tests performed on existing buildings with this structural system. This study investigates the dynamic structural properties of a typical nine-story reinforced concrete flat plate-wall building by forced vibration testing and develops its three-dimensional (3-D) linear elastic finite element structural model. The finite element model that uses the modulus of elasticity for concrete in ACI 318 predicts the natural vibration periods well. Mode shapes are also in good agreement with the test results. Door and window openings in the shear walls, and the basement with peripheral wall emerge as modeling considerations that have the most significant impact on structural system dynamic properties.

Processing forced vibration test records of structural systems using the analytic signal

2020 ◽  
pp. 107754632095792
Author(s):  
Ozan Cem Celik ◽  
Hakkı Polat Gülkan
Keyword(s):  
Reinforced Concrete ◽  
Forced Vibration ◽  
Dynamic Properties ◽  
Analytic Signal ◽  
Mode Shapes ◽  
Vibration Test ◽  
Structural Systems ◽  
Vibration Source ◽  
Response Curves ◽  
Forced Vibration Test

This article presents the use of the analytic signal procedure for processing the large volume of structural vibration data recorded in forced vibration tests. The analytic signal facilitates the computationally laborious task of extracting the steady-state amplitude for each response measure of interest from the recorded accelerations throughout the building at each operated frequency of the forced vibration source. The implementation of the signal processing procedure introduced here is illustrated in deriving the acceleration–frequency response curves from the forced vibration test of the first permanently instrumented building in Turkey. This reinforced concrete building, subsequently strengthened with cast-in-place reinforced concrete infill shear walls, is located in close proximity to the North Anatolian Fault. Later, system identification of the building yields the in situ structural system dynamic properties for the first translational and torsional vibration modes, which are compared with those identified from the ambient vibrations of the building recorded following its forced vibration test. The analytic signal procedure is a convenient tool for the rapid and correct derivation for mode shapes and associated frequencies and damping ratios from forced vibration testing of structural systems.

Effect of Crack Orientation on Laminated CFRP Composites Using Vibration and Numerical Analysis

2021 ◽  
Vol 79 (11) ◽  
pp. 1081-1093
Author(s):  
Essam Moustafa ◽  
Khalid Almitani ◽  
Hossameldin Hussein
Keyword(s):  
Composite Structures ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Composite Plates ◽  
Mode Shapes ◽  
Crack Orientation ◽  
Test Plate ◽  
Cfrp Composites ◽  
Cfrp Composite ◽  
Vibration Tests

Crack orientation, a critical parameter, significantly affects the dynamic properties of composite structures. Experimental free vibration tests were conducted on carbon fiber–reinforced polymer (CFRP) composite plates at room temperature with different crack orientations. Dynamic properties such as damping ratio, natural frequency, and storage modulus were measured using a four-channel dynamic pulse analyzer. Multi-sensors were mounted on the test plate to pick up the vibration signals. Experimental modal analysis was performed to identify the first three mode shapes of the defective plates. A numerical model using ANSYS software was developed via parametric investigation to predict the correlation between crack orientation and resonant frequencies with corresponding mode shapes. The orientation of the introduced cracks had a significant effect on the dynamic properties of CFRP composites. Vertical cracks had the most significant influence on the eigenvalues of the mode shape frequencies. Furthermore, the damping ratio was an effective method to detect the cracks in CFRP composites.

Analyse dynamique de l'interaction pont-véhicules pour les ponts routiers. II. Application au pont de Senneterre au Québec

1998 ◽  
Vol 25 (1) ◽  
pp. 174-187 ◽  
Author(s):  
Kamel Henchi ◽  
Martin Talbot ◽  
Mario Fafard
Keyword(s):  
Amplification Factor ◽  
Experimental Tests ◽  
Mode Shapes ◽  
Dynamic Amplification Factor ◽  
The Road ◽  
Beam Elements ◽  
Road Profile ◽  
Specific Loading ◽  
Dynamic Amplification

In this paper, an application of the algorithm for the dynamic analysis of bridge-vehicles interaction that the authors developed in the preceeding paper is presented. The numerical results are compared to the results obtained from experimental tests of frequencies and mode shapes and from forced vibrations carried out on the Senneterre bridge located in Quebec. The numerical model of the bridge is obtained by tridimensional finite element modeling, using shell and beam elements, and taking into account bridge-vehicles interaction and the road profile in a realistic way. The numerical vehicle model used in the province of Quebec is represented in a discrete form based on mechanical parameters calibrated and adjusted according to experimental results. A parametric study was then carried out. The results of this study allow us to present some recommendations with regard to bridge resistance to dynamic effects and the determination of a dynamic amplification factor based on the specific loading conditions of the bridge. Key words: shell, dynamic, finite elements, interaction, bridge, roughness, vehicle, amplification factor, experimental tests.[Journal translation]

Measured natural periods of concrete shear wall buildings: insights for the design of Canadian buildings

2012 ◽  
Vol 39 (8) ◽  
pp. 867-877 ◽  
Author(s):  
Damien Gilles ◽  
Ghyslaine McClure
Keyword(s):  
Seismic Analysis ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Shear Wall ◽  
Mode Shapes ◽  
Design Stage ◽  
Base Shear ◽  
Period Equation ◽  
Input Load ◽  
Structural Engineers

Structural engineers routinely use rational dynamic analysis methods for the seismic analysis of buildings. In linear analysis based on modal superposition or response spectrum approaches, the overall response of a structure (for instance, base shear or inter-storey drift) is obtained by combining the responses in several vibration modes. These modal responses depend on the input load, but also on the dynamic characteristics of the building, such as its natural periods, mode shapes, and damping. At the design stage, engineers can only predict the natural periods using eigenvalue analysis of structural models or empirical equations provided in building codes. However, once a building is constructed, it is possible to measure more precisely its dynamic properties using a variety of in situ dynamic tests. In this paper, we use ambient motions recorded in 27 reinforced concrete shear wall (RCSW) buildings in Montréal to examine how various empirical models to predict the natural periods of RCSW buildings compare to the periods measured in actual buildings under ambient loading conditions. We show that a model in which the fundamental period of RCSW buildings varies linearly with building height would be a significant improvement over the period equation proposed in the 2010 National Building Code of Canada. Models to predict the natural periods of the first two torsion modes and second sway modes are also presented, along with their uncertainty.

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