scholarly journals Measurement of Quasi-Static and Dynamic Displacements of Footbridges Using the Composite Instrument of a Smartstation and an Accelerometer: Case Studies

2020 ◽  
Vol 12 (16) ◽  
pp. 2635 ◽  
Author(s):  
Jiayong Yu ◽  
Zhen Fang ◽  
Xiaolin Meng ◽  
Yilin Xie ◽  
Qian Fan
Keyword(s):  
Case Studies ◽  
Displacement Component ◽  
Dynamic Responses ◽  
Frequency Range ◽  
Static Displacement ◽  
Monitoring Method ◽  
Bridge Structures ◽  
Overall Performance ◽  
Chebyshev Filter ◽  
Potential Tool

Monitoring the dynamic responses of bridge structures has received considerable attention. It is important to synchronously measure both the quasi-static and dynamic displacements of bridge structures. However, the traditional accelerometer method cannot capture the quasi-static displacement component, although it can detect the dynamic displacement component. To this end, a novel composite instrument of a smartstation was proposed to monitor vibration displacements of footbridges. Full-scale experiments were conducted on a footbridge to validate the feasibility of the composite instrument-based monitoring method. A Chebyshev filter and wavelet algorithms were developed to process the composite instrument measurements. It was concluded that the measurement noise of the composite instrument was mainly distributed in a frequency range of 0–0.1 Hz. In two case studies with displacement peaks of 5.7–10.0 mm and 1.3– 2.5 mm, the composite instrument accurately identified the quasi-static and dynamic displacements. The composite instrument will be a potential tool for monitoring structural dynamics because of its enhanced overall performance.

scholarly journals Measurement of Quasi-static and Dynamic Displacements of Footbridges Using the Composite Instrument of Smartstation and Accelerometer: Case Studies

2020 ◽  
Author(s):  
Jiayong Yu ◽  
Zhen Fang ◽  
Xiaolin Meng ◽  
Yilin Xie ◽  
Qian fan
Keyword(s):  
Case Studies ◽  
Displacement Component ◽  
Dynamic Monitoring ◽  
Response Monitoring ◽  
Monitoring Method ◽  
Structural Dynamic ◽  
Bridge Structures ◽  
Overall Performance ◽  
Chebyshev Filter ◽  
Potential Tool

Dynamic response monitoring of bridge structures has received considerable attention. It is important to synchronously measure both quasi-static and dynamic displacements of bridge structures. However, traditional accelerometer method cannot capture quasi-static displacement component although it can detect dynamic displacement component. To this end, a novel composite instrument of smartstation was proposed to monitor vibration displacements of footbridges. Full-scale experiments were conducted on a footbridge to validate the feasibility of the composite instrument-based monitoring method. Chebyshev filter and wavelet algorithms were developed to process the composite instrument measurements. Conclusions were drawn that the measurement noise of the composite instrument mainly distributed in a frequency range of 0 - 0.1 Hz. In two case studies with displacement peaks of 5.7 - 10.0 mm and 1.3 to 2.5 mm, the composite instrument accurately identified their quasi-static and dynamic displacements. The composite instrument will be a potential tool for structural dynamic monitoring with the enhancement of its overall performance.

Estimation of bridge static response and vehicle weights by frequency response analysis

1998 ◽  
Vol 25 (4) ◽  
pp. 631-639 ◽  
Author(s):  
G Thater ◽  
P Chang ◽  
D R Schelling ◽  
C C Fu
Keyword(s):  
Dynamic Effect ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Static Response ◽  
Actual Weight ◽  
Service Testing ◽  
Weigh In Motion ◽  
Moving Vehicles ◽  
Bridge Structures ◽  
Truck Weight

A methodology is developed to more accurately estimate the static response of bridges due to moving vehicles. The method can also be used to predict dynamic responses induced by moving vehicles using weigh-in-motion (WIM) techniques. Historically, WIM is a well-developed technology used in highway research, since it has the advantage of allowing for the stealthy automatic collection of weight data for heavy trucks. However, the lack of accuracy in determining the dynamic effect in bridges has limited the potential for its use in estimating the fatigue life of bridge structures and their components. The method developed herein amends the current WIM procedures by filtering the dynamic responses accurately using the Fast Fourier Transform (FFT). Example applications of the proposed method are shown by using computer-generated data. The method is fast and improves the predicted truck weight up to 5% of the actual weight, as compared to errors up to 10% using the current WIM methods.Key words: weigh-in-motion, digital filters, FFT, bridge dynamics, in-service testing.

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.

Adaptive Amplifier for a Test Vehicle Moving Over Bridges: Theoretical Study

2020 ◽  
pp. 2150042
Author(s):  
Y. B. Yang ◽  
Z. L. Wang ◽  
K. Shi ◽  
H. Xu ◽  
J. P. Yang
Keyword(s):  
Dynamic Responses ◽  
Vehicle Speed ◽  
Test Vehicle ◽  
Vehicle Performance ◽  
Single Degree Of Freedom ◽  
Closed Form Solutions ◽  
Numerical Studies ◽  
Element Simulation ◽  
Road Roughness ◽  
Overall Performance

A vibration amplifier is first proposed for adding to a test vehicle to enhance its capability to detect frequencies of the bridge under scanning. The test vehicle adopted is of single-axle and modeled as a single degree-of-freedom (DOF) system, which was proved to be successful in previous studies. The amplifier is also modeled as a single-DOF system, and the bridge as a simple beam of the Bernoulli–Euler type. To unveil the mechanism involved, closed-form solutions were first derived for the dynamic responses of each component, together with the transmissibility from the vehicle to amplifier. Also presented is a conceptual design for the amplifier. The approximations adopted in the theory were verified to be acceptable by the finite element simulation without such approximations. Since road roughness can never be avoided in practice and the test vehicle has to be towed by a tractor in the field test, both road roughness and the tractor are included in the numerical studies. For the general case, when the amplifier is not tuned to the vehicle frequency, the bridge frequencies can better be identified from the amplifier than vehicle response, and the tractor is helpful in enhancing the overall performance of the amplifier. Besides, the amplifier can be adaptively adjusted to target and detect the bridge frequency of concern. For the special case when the amplifier is tuned to the vehicle frequency, the amplifier can improve the vehicle performance by serving as a tuned mass damper, as conventionally known. This case is of limited use since it does not allow us to target the bridge frequencies. Both bridge damping and vehicle speed are also assessed with their effects addressed.

scholarly journals A comparison between the dynamics of horizontal and vertical axis offshore floating wind turbines

2015 ◽  
Vol 373 (2035) ◽  
pp. 20140076 ◽  
Author(s):  
M. Borg ◽  
M. Collu
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Static Stability ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Frequency Range ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Support Structure

The need to further exploit offshore wind resources in deeper waters has led to a re-emerging interest in vertical axis wind turbines (VAWTs) for floating foundation applications. However, there has been little effort to systematically compare VAWTs to the more conventional horizontal axis wind turbine (HAWT). This article initiates this comparison based on prime principles, focusing on the turbine aerodynamic forces and their impact on the floating wind turbine static and dynamic responses. VAWTs generate substantially different aerodynamic forces on the support structure, in particular, a potentially lower inclining moment and a substantially higher torque than HAWTs. Considering the static stability requirements, the advantages of a lower inclining moment, a lower wind turbine mass and a lower centre of gravity are illustrated, all of which are exploitable to have a less costly support structure. Floating VAWTs experience increased motion in the frequency range surrounding the turbine [number of blades]×[rotational speed] frequency. For very large VAWTs with slower rotational speeds, this frequency range may significantly overlap with the range of wave excitation forces. Quantitative considerations are undertaken comparing the reference NREL 5 MW HAWT with the NOVA 5 MW VAWT.

scholarly journals Experiment and Numerical Simulation of the Dynamic Response of Bridges under Vibratory Compaction of Bridge Deck Asphalt Pavement

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
An-Ping Peng ◽  
Han-Cheng Dan ◽  
Dong Yang
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Field Experiments ◽  
Bridge Deck ◽  
Asphalt Pavement ◽  
Dynamic Responses ◽  
Structural Safety ◽  
Cross Sectional ◽  
Bridge Structures ◽  
Vibratory Compaction

Vibratory compaction of bridge deck pavement impacts the structural integrity of bridges to certain degrees. In this study, we analyzed the dynamic response of different types of concrete-beam bridges (continuous beam and simply supported beam) with different cross-sectional designs (T-beam and hollow-slab beam) under vibratory compaction of bridge deck asphalt pavement. The dynamic response patterns of the dynamic deformation and acceleration of bridges under pavement compaction were obtained by performing a series of field experiments and a three-dimensional finite element simulation. Based on the finite element model, the dynamic responses of bridge structures with different spans and cross-sectional designs under different working conditions of vibratory compaction were analyzed. The use of different vibration parameters for different bridge structures was proposed to safeguard their structural safety and reliability.

STATIC DISPLACEMENT COMPONENT AND ITS SIGNIFICANCE IN NONLINEAR ULTRASONIC MEASUREMENTS

2008 ◽  
Author(s):  
Karthik Thimmavajjula Narasimha ◽  
Elankumaran. Kannan ◽  
Krishnan Balasubramaniam ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Displacement Component ◽  
Static Displacement ◽  
Ultrasonic Measurements ◽  
Nonlinear Ultrasonic
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