scholarly journals Experimental and Numerical Investigation on Dynamic Properties and Human-Induced Vibrations of an Asymmetric Steel-Plated Stress-Ribbon Footbridge

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Yi Zhang ◽  
Wei He ◽  
Jiewen Zhang ◽  
Hua Dong
Keyword(s):  
Dynamic Properties ◽  
Element Model ◽  
Ambient Vibration ◽  
Subspace Identification ◽  
Stochastic Subspace Identification ◽  
Deck Panels ◽  
Single Person ◽  
Ambient Vibration Testing ◽  
Measurement Results ◽  
Comprehensive Study

This paper presents a comprehensive study on dynamic properties and human-induced vibrations of a slender asymmetric steel-plated stress-ribbon footbridge via both experimental and analytical methods. Bridge modal test was conducted using both ambient vibration testing and impact methods. Modal properties of the bridge were identified based on stochastic subspace identification and peak-pick techniques. Results show that the bridge is characterized by closely spaced modes with low natural frequencies and small damping ratios (<0.002). A sophisticated finite element model that incorporates pretension of the stress ribbon and contribution of deck panels is developed and proven to be capable of reflecting the main dynamic characteristics of the bridge. Human-induced vibrations were measured considering synchronization cases, including single-person and small group walking as well as random walking cases. A theoretical model that takes into account human-structure interaction was developed, treating the single walking person as an SDOF system with biomechanical excited force. The validity of the model was further verified by measurement results.

Analysis of a damaged 12-storey frame-wall concrete building during the 2010 Haiti earthquake — Part II: Nonlinear numerical simulations

2013 ◽  
Vol 40 (8) ◽  
pp. 803-814 ◽  
Author(s):  
Benoit Boulanger ◽  
Patrick Paultre ◽  
Charles-Philippe Lamarche
Keyword(s):  
Structural Damage ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Shear Walls ◽  
Element Model ◽  
Companion Paper ◽  
Ambient Vibration ◽  
Wall Structure ◽  
Haiti Earthquake ◽  
Concrete Building

After the 2010 Haiti earthquake, which destroyed a significant part of the seismically vulnerable city of Port-au-Prince, the country’s capital, a 12-storey reinforced concrete building that behaved well was investigated to understand its dynamic response. This paper completes the experimental work presented in a companion paper, in which the dynamic properties of the building were obtained from ambient vibration tests, and from which a finite-element model was updated. This paper’s main objectives are: (i) to understand the causes that led to the observed structural damage; and (ii) to estimate the likely seismic excitation at the site of the building. Several nonlinear analyses involving various ground motion intensities were conducted and the results were compared with the damage reported during the on-site survey. The numerical models reproduced the observed damages well and helped to explain them. The overall response of the mixed stiff frame–wall structure was clearly dominated by the high stiffness of the shear walls, showing that this type of structural system helps in keeping reasonable interstorey drift levels. Overall, the building’s structure seems to have responded linearly to all the ground motions investigated, but deformation demands imposed to the frame by the shear walls lead to local damages.

Research on Temperature Effect on the Natural Frequencies of Continuous Beams Based on Stochastic Subspace Identification

2013 ◽  
Vol 706-708 ◽  
pp. 1545-1548
Author(s):  
Yong Chun Cheng ◽  
Yu Ping Shi ◽  
Guo Jin Tan
Keyword(s):  
Dynamic Response ◽  
Temperature Effect ◽  
Natural Frequencies ◽  
Element Model ◽  
Effect Of Temperature ◽  
Subspace Identification ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Stochastic Subspace Identification ◽  
Girder Bridges

Natural frequencies are of great value to bridge structural design, health monitoring and detection. Related research data show that the ambient temperature can affect the natural frequencies of the continuous box-girder bridges. In order to research the effect of temperature on the bridge structure and conclude the influence law, theoretical analysis of temperature effect on the natural frequencies of the continuous box girder bridges is conducted based on the stochastic subspace identification. First, the finite element model of the bridge is built to conduct thermal-structural coupling analysis. Then regard the analysis results as the original state, and exert white noise excitation on the structure to obtain the dynamic response of the structure. And then analyze the dynamic response based on the stochastic subspace identification and calculate the natural frequencies of the bridges under the temperature effect. At last, based on the practical project of one 3-span continuous box-girder bridge, the validity and the reliability of this method is verified.

Structural System Identification of Elevated Steel Water Tank Using Ambient Vibration Test and Calibration of Numerical Model

2020 ◽  
Vol 20 (10) ◽  
pp. 2071010
Author(s):  
Mohammad Alembagheri ◽  
Maria Rashidi ◽  
Mohammad Seyedkazemi
Keyword(s):  
System Identification ◽  
Numerical Model ◽  
Dynamic Properties ◽  
Ambient Vibration ◽  
Water Tank ◽  
Ambient Vibration Test ◽  
Vibration Data ◽  
Steel Material ◽  
Ambient Vibration Testing ◽  
Structural System Identification

This research aims to investigate the feasibility of using ambient vibration testing for system identification of an elevated water tank. To identify the natural dynamic properties, the experimental study is carried out on an elevated steel water tank located in Tehran. The tank is instrumented with a sensitive velocimeter sensor (microtremor), and the ambient velocity of the tank is recorded for 30[Formula: see text]min in three orthogonal axes. Employing the peak-picking method in the frequency domain, the fundamental frequency of the tank is determined as about 1.9[Formula: see text]Hz. Then, the numerical model of the tank is generated and calibrated based on the obtained data. In the primary modeling, the values of natural frequencies of the tank are in good agreement with the results of the ambient vibration data. This finding is judged to be reasonable considering no clear sign of corrosion in the steel material.

scholarly journals Vibration-based damage localization and quantification in a pretensioned concrete girder using stochastic subspace identification and particle swarm model updating

2019 ◽  
Vol 19 (2) ◽  
pp. 587-605 ◽  
Author(s):  
Alessandro Cancelli ◽  
Simon Laflamme ◽  
Alice Alipour ◽  
Sri Sritharan ◽  
Filippo Ubertini
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Stiffness Matrix ◽  
Particle Swarm ◽  
Element Model ◽  
Subspace Identification ◽  
Reduced Order ◽  
Stochastic Subspace Identification ◽  
Modal Properties ◽  
Pretensioned Concrete

A popular method to conduct structural health monitoring is the spatio-temporal study of vibration signatures, where vibration properties are extracted from collected vibration responses. In this article, a novel methodology for extracting and analyzing distributed acceleration data for condition assessment of bridge girders is proposed. Three different techniques are fused, enabling robust damage detection, localization, and quantification. First, stochastic subspace identification is used as an output-only method to extract modal properties of the monitored structure. Second, a reduced-order stiffness matrix is reconstructed from the stochastic subspace identification data using the system equivalent reduction expansion process. Third, a particle swarm optimization algorithm is used to update a finite element model of the bridge girder to match the extracted reduced-order stiffness matrix and modal properties. The proposed approach is first verified through numerically simulated data of the girder and then validated using experimental data obtained from a full-scale pretensioned concrete beam that experienced two distinct states of damage. Results show that the method is capable of localizing and quantifying damages along the girder with good accuracy, and that results can be used to create a high-fidelity finite element model of the girder that could be leveraged for condition prognosis and forecasting.

scholarly journals Identification of Historical Veziragasi Aqueduct Using the Operational Modal Analysis

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
E. Ercan ◽  
A. Nuhoglu
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Model Updating ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Element Model ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Ambient Vibration ◽  
Mode Shapes

This paper describes the results of a model updating study conducted on a historical aqueduct, called Veziragasi, in Turkey. The output-only modal identification results obtained from ambient vibration measurements of the structure were used to update a finite element model of the structure. For the purposes of developing a solid model of the structure, the dimensions of the structure, defects, and material degradations in the structure were determined in detail by making a measurement survey. For evaluation of the material properties of the structure, nondestructive and destructive testing methods were applied. The modal analysis of the structure was calculated by FEM. Then, a nondestructive dynamic test as well as operational modal analysis was carried out and dynamic properties were extracted. The natural frequencies and corresponding mode shapes were determined from both theoretical and experimental modal analyses and compared with each other. A good harmony was attained between mode shapes, but there were some differences between natural frequencies. The sources of the differences were introduced and the FEM model was updated by changing material parameters and boundary conditions. Finally, the real analytical model of the aqueduct was put forward and the results were discussed.

Finite Element Model Updating of a PSC Box Girder Bridge Using Ambient Vibration Test

2010 ◽  
Vol 168-170 ◽  
pp. 2263-2270 ◽  
Author(s):  
Matthew Hiatt ◽  
Annika Mathiasson ◽  
John Okwori ◽  
Seung Seop Jin ◽  
Shen Shang ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Element Model ◽  
Ambient Vibration ◽  
Research Experience ◽  
Ambient Vibration Test ◽  
Modal Properties ◽  
Ambient Vibration Testing ◽  
Frequency Domain Decomposition

In this paper, in-field ambient vibration testing of a highway bridge in South Korea under traffic loadings has been conducted to update its finite element model for future predictive analysis and diagnosis purpose. The research results presented in this paper are outcomes from an international REU (Research Experience for Undergraduates) program in smart structures funded by US-NSF (National Science Foundation) and hosted abroad by the Korean Advanced Institute of Science and Technology (KAIST). The monitoring, modeling, and model updating of civil infrastructures are vital in maintaining new design and maintenance standards. Using the frequency domain decomposition (FDD), experimental modal properties of the structure were found and, after a finite element model was created and updated based on the modal properties. From the results, it has been concluded that (a) the FDD method successfully identified the modal characteristics of the structure from ambient vibration, (b) that model updating improved the accuracy of the finite element model, (c) Representing the structural supports as springs in the FEM improved the results from the ideally supported model.

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