scholarly journals Application of the Hilbert-Huang Transform for Identification of Changes in Boundary Conditions of a Bridge Using Vibration Data due to Traffic

2013 ◽  
Vol 569-570 ◽  
pp. 892-899
Author(s):  
Arturo González ◽  
Hussein Aied
Keyword(s):  
Environmental Changes ◽  
Structural Response ◽  
Ambient Vibration ◽  
Beam Model ◽  
Elastomeric Bearings ◽  
Hilbert Huang Transform ◽  
Vibration Data ◽  
Mode Decomposition ◽  
Bearing Stiffness ◽  
Frequency Domain Response

The translational restraints associated to pin and rocker bearings are typically idealized in the form of fixed and free conditions. However, elastomeric bearings need to be represented with springs to reasonably predict the time- and frequency-domain response of bridges under traffic-induced vibrations. Therefore, changes in the response of these bearings are common as a result of aging, deterioration, variation in loading levels and/or environmental changes. The latter makes difficult to discern if changes in the frequency content of the structural response to ambient vibration are due to changes in temperature, changes in normal operational loads or the occurrence of damage. In this paper, the bridge is idealized by a beam model supported on a hysteretic translational sprung support. The purpose is twofold: (a) to gather a better understanding of the variations of the bridge response with bearing performance; and (b) to be able to quickly identify an anomaly in the bearing. Empirical Mode Decomposition and the Hilbert-Huang Transform are employed to capture changes in the bearing stiffness from the bridge response.

Coupled torsional dynamic analysis of a multistory building

1973 ◽  
Vol 63 (3) ◽  
pp. 1025-1039
Author(s):  
Bruce M. Douglas ◽  
Thomas E. Trabert
Keyword(s):  
Ground Motion ◽  
Degrees Of Freedom ◽  
Seismic Waves ◽  
Structural Response ◽  
Tall Buildings ◽  
Strong Motion ◽  
Ambient Vibration ◽  
Simultaneous Application ◽  
Vibration Data ◽  
Horizontal Ground Motion

abstract The coupled bending and torsional vibrations of a relatively symmetric 22-story reinforced concrete building in Reno, Nevada are studied. Analytical results are compared with observations obtained during the nuclear explosion FAULTLESS and to ambient vibration data. The fundamental periods of vibration observed during FAULTLESS were (TNS = 1.42, TEW = 1.81, TTORSION = 1.12 sec), and the calculated periods were (TNS = 2.14, TEW = 2.07, TTORSION = 1.90 sec). It was estimated that between 25 and 45 per cent of the total available nonstructural stiffness was required to explain the differences in the observed and calculated fundamental periods. Each floor diaphragm in the system was allowed three degrees of freedom-two translations and a rotation. It was found that coupled torsional motions can influence the response of structural elements near the periphery of the structure. Strong-motion structural response calculations comparing the simultaneous use of both components of horizontal ground motion to a single component analysis showed that the simultaneous application of both components of ground motion can significantly alter the response of lateral load-carrying elements. Differences of the order of 45 per cent were observed in the frames near the ends of the structure. Also, it was shown that the overall response of tall buildings is sensitive not only to the choice of input ground motion but also to the orientation of the structure with respect to the seismic waves.

scholarly journals Natural Frequencies and Modal Damping Ratios Identification of Civil Structures from Ambient Vibration Data

2006 ◽  
Vol 13 (4-5) ◽  
pp. 429-444 ◽  
Author(s):  
Minh-Nghi Ta ◽  
Joseph Lardiès ◽  
Berthillier Marc
Keyword(s):  
Structural Response ◽  
Response Prediction ◽  
Ambient Vibration ◽  
Modal Parameter ◽  
Engineering Structures ◽  
Double Row ◽  
Transform Method ◽  
Vibration Data ◽  
Cable Stayed Bridge ◽  
Modal Damping

Damping is a mechanism that dissipates vibration energy in dynamic systems and plays a key role in dynamic response prediction, vibration control as well as in structural health monitoring during service. In this paper a time domain and a time-scale domain approaches are used for damping estimation of engineering structures, using ambient response data only. The use of tests under ambient vibration is increasingly popular today because they allow to measure the structural response in service. In this paper we consider two engineering structures excited by ambient forces. The first structure is the 310 m tall TV tower recently constructed in the city of Nanjing in China. The second example concerns the Jinma cable-stayed bridge that connects Guangzhou and Zhaoqing in China. It is a single tower, double row cable-stayed bridge supported by 112 stay cables. Ambient vibration of each cable is carried out using accelerometers. From output data only, the modal parameter are extracted using a subspace method and the wavelet transform method.

Detection of Building Response Changes Using Deconvolution Interferometry: A Case Study in Bogota, Colombia

2021 ◽  
Author(s):  
Nathalia Jaimes ◽  
Germán A. Prieto ◽  
Carlos Rodriguez
Keyword(s):  
Impulse Response Function ◽  
Structural Response ◽  
Monitoring Network ◽  
Aftershock Sequence ◽  
Ambient Vibration ◽  
Velocity Variation ◽  
Reinforced Concrete Structure ◽  
Engineering Structures ◽  
Vibration Data ◽  
Deconvolution Interferometry

Abstract Seismic structural health monitoring allows for the continuous evaluation of engineering structures by monitoring changes in the structural response that can potentially localize associated damage that has occurred. For the first time in Colombia, a permanent and continuous monitoring network has been deployed in a 14-story ecofriendly steel-frame building combined with a reinforced concrete structure in downtown Bogota. The six three-component ETNA-2 accelerometers recorded continuously for 225 days between July 2019 and February 2020. We use deconvolution-based seismic interferometry to calculate the impulse response function (IRF) using earthquake and ambient-vibration data and a stretching technique to estimate velocity variations before and after the Ml 6.0 Mesetas earthquake and its aftershock sequence. A consistent and probably permanent velocity variation (2% reduction) is detected for the building using ambient-vibration data. In contrast, a 10% velocity reduction is observed just after the mainshock using earthquake-based IRFs showing a quick recovery to about 2%. A combination of both earthquake-based and ambient-vibration-based deconvolution interferometry provides a more complete picture of the state of health of engineering structures.

Finite Deformation Stiffness of Sliding Elastomeric Bearings

2011 ◽  
Vol 374-377 ◽  
pp. 1858-1862
Author(s):  
Jian Chun Xiao ◽  
Peng Liu ◽  
Ke Jian Ma
Keyword(s):  
Parametric Analysis ◽  
Steel Plates ◽  
Structural Behavior ◽  
Analysis Method ◽  
Force Vector ◽  
Elastomeric Bearings ◽  
Before And After ◽  
Bearing Stiffness ◽  
Vector Formula

Anchor bolts are set in some elastomeric bearings of large-span column-supported spatial steel roofs. Besides helping the bearing in-site assembly, the bolts play the roles of sliding position limitation and vertical anchorage. To analyze the effect of bearings on nonlinear structural behavior, the bearing stiffness change is studied just before and after the elastomer pad is in contact with the bolts. For the bearing that the pad is glued with the top/bottom steel plates, three kinds of relation of pad and bolts are discussed and an approximate horizontal stiffness formula is obtained with parametric analysis method. Based on the analysis results a stiffness expression for sliding elastomeric bearings is deduced. To solve the computational problem caused by the bearing stiffness changes, an improved imbalance force vector formula is proposed. Case study shows that the bolts have influence upon the computed results more significantly.

Ensemble Empirical Mode Decomposition and Sparsity Measurement as Tools Enhancing the Gear Diagnostic Capabilities of Time Synchronous Averaging

2017 ◽  
Vol 09 (02) ◽  
pp. 1750004 ◽  
Author(s):  
Pawel Rzeszucinski ◽  
Michal Juraszek ◽  
James R. Ottewill
Keyword(s):  
Empirical Mode Decomposition ◽  
Ensemble Empirical Mode Decomposition ◽  
Diagnostic Information ◽  
Optimal Parameters ◽  
Vibration Data ◽  
Mode Decomposition ◽  
Ultrasound Signal ◽  
Diagnostic Capabilities ◽  
Mixing Problem ◽  
Mode Mixing

The paper introduces the concept of exploring the potential of Ensemble Empirical Mode Decomposition (EEMD) and Sparsity Measurement (SM) in enhancing the diagnostic information contained in the Time Synchronous Averaging (TSA) method used in the field of gearbox diagnostics. EEMD was created as a natural improvement of the Empirical Mode Decomposition which suffered from a so-called mode mixing problem. SM is heavily used in the field of ultrasound signal processing as a tool for assessing the degree of sparsity of a signal. A novel process of automatically finding the optimal parameters of EEMD is proposed by incorporating a Form Factor parameter, known from the field of electrical engineering. All these elements are combined and applied on a set of vibration data generated on a 2-stage gearbox under healthy and faulty conditions. The results suggest that combining these methods may increase the robustness of the condition monitoring routine, when compared to the standard TSA used alone.

scholarly journals Dynamic Study of a Rooftop Vertical Axis Wind Turbine Tower Based on an Automated Vibration Data Processing Algorithm

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3135 ◽  
Author(s):  
Ying Wang ◽  
Wensheng Lu ◽  
Kaoshan Dai ◽  
Miaomiao Yuan ◽  
Shen-En Chen
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Dynamic Responses ◽  
Ambient Vibration ◽  
Structural Vibration ◽  
Vertical Axis Wind Turbine ◽  
Mode Identification ◽  
Stochastic Subspace Identification ◽  
Vibration Data ◽  
Vibration Responses

When constructed on tall building rooftops, the vertical axis wind turbine (VAWT) has the potential of power generation in highly urbanized areas. In this paper, the ambient dynamic responses of a rooftop VAWT were investigated. The dynamic analysis was based on ambient measurements of the structural vibration of the VAWT (including the supporting structure), which resides on the top of a 24-story building. To help process the ambient vibration data, an automated algorithm based on stochastic subspace identification (SSI) with a fast clustering procedure was developed. The algorithm was applied to the vibration data for mode identification, and the results indicate interesting modal responses that may be affected by the building vibration, which have significant implications for the condition monitoring strategy for the VAWT. The environmental effects on the ambient vibration data were also investigated. It was found that the blade rotation speed contributes the most to the vibration responses.

scholarly journals Damage detection based on damping analysis of ambient vibration data

2008 ◽  
pp. n/a-n/a ◽  
Author(s):  
Michele Frizzarin ◽  
Maria Q. Feng ◽  
Paolo Franchetti ◽  
Serdar Soyoz ◽  
Claudio Modena
Keyword(s):  
Damage Detection ◽  
Ambient Vibration ◽  
Vibration Data
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