scholarly journals Dynamic Test of a Viaduct on the Orastie–Sibiu Highway

2017 ◽  
Vol 6 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Ghindea Cristian Lucian ◽  
Răcănel Ionuţ Radu ◽  
Cruciat Radu Iuliu
Keyword(s):  
Dynamic Testing ◽  
Numerical Models ◽  
Damping Ratio ◽  
Dynamic Test ◽  
Time History ◽  
Element Model ◽  
Dynamic Impact ◽  
Bridge Superstructure ◽  
Special Solutions ◽  
Dynamic Impact Factor

Abstract Dynamic testing of bridges has as target to establish their response on pulse forces between the wheels and unevenness of road surface. Generally, during the tests, real time accelerations or deformations are to be measured and which through successive processing methods lead to other data as velocities, displacements, dynamic impact factor, but also the damping ratio. In order to validate the bridge response following testing, the measured data are compared both with allowable limits existing in standards and with the results obtained using analytical or numerical models. In Romania, the dynamic testing of bridges is recommended by the current standards, only for important bridges, erected in complex or special solutions and also for large span bridges. The aim of this paper is to outline the results obtained from the on-site measurements during dynamic testing of a viaduct placed on the motorway A1, sector Orăştie-Sibiu. The bridge superstructure is a composite one, continuous girder on 12 spans: 40+10×60+40 m, the substructure consisting in 11 piers with lamellar elevations and variable height in the range 8.50-24m. In the paper a finite element model is also presented which was used for time-history analyses using an impulse type load. Finally, the results obtained on the site and using the numerical model are compared and discussed.

Analysis of Dynamic Performance of Rigid Pile Composite Foundation

2012 ◽  
Vol 256-259 ◽  
pp. 648-651
Author(s):  
Gui Lin Sheng ◽  
Cai Li Su ◽  
De Hui Liu
Keyword(s):  
Response Pattern ◽  
Similarity Theory ◽  
Dynamic Performance ◽  
Dynamic Test ◽  
Time History ◽  
Element Model ◽  
Composite Foundation ◽  
Group Model ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

The paper established 3-D finite element model, studied the response pattern of rigid pile composite foundation under earthquake loading with time history analysis method. According to similarity theory, this paper established rigid pile composite foundation pile group model, analyzed the response pattern of it with pseudo-dynamic test methods. And compared and analyzed the results which were obtained by different methods, based on these analyses, some conclusions which may be of some value for anti-seismic design of this type of composite foundations are drawn

scholarly journals Numerical Simulations of Dynamic Behavior of Polyurea Toughened Steel Plates under Impact Loading

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chien-Chung Chen ◽  
Daniel G. Linzell
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Impact Loading ◽  
Numerical Models ◽  
Model Development ◽  
Time History ◽  
Element Model ◽  
Steel Plates ◽  
Numerical Work

The objective of the work discussed herein is to develop a nonlinear 3D finite element model to simulate dynamic behavior of polyurea toughened steel plates under impact loading. Experimental and numerical work related to model development are presented. Material properties are incorporated into numerical models to account for strain-rate effects on the dynamic behavior of polyurea and steel. One bare steel plate and four polyurea toughened steel plates were tested under impact loading using a pendulum impact device. Displacement time-history data from experimental work was used to validate the numerical models. Details on material model construction, finite element model development, and model validation are presented and discussed. Results indicate that the developed numerical models can reasonably predict dynamic response of polyurea toughened steel plates under impact loading.

Dynamic Testing under Nonsinusoidal Conditions and the Consequences of Nonlinearity for Service Performance

1987 ◽  
Vol 60 (5) ◽  
pp. 870-887 ◽  
Author(s):  
J. A. Harris
Keyword(s):  
Harmonic Analysis ◽  
Dynamic Behavior ◽  
Dynamic Testing ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Time History ◽  
Test System ◽  
Service Environment ◽  
Harmonic Components ◽  
Vibration Tests

Abstract In this work, nonlinearity in the dynamic behavior of rubber has been considered. In order to understand its effects in a service environment involving complex patterns of vibration, it has been necessary to clarify the derivations of dynamic properties for the sinusoidal excitation that is conventionally used in testing. Using the fundamental frequency components as a basis, non-linearity can be quantified by the harmonic components that it produces. A dynamic test system has been developed which incorporates the ability to perform a harmonic analysis, and the usefulness of this has been demonstrated. Harmonic analysis has enabled the dynamic behavior of rubber to be quantified under complex, periodic waveforms. This is necessary for filled rubbers, because their nonlinearity means that a superposition on their properties from sinusoidal tests is incorrect. Examples of this approach for assessing dynamic behavior range from shock mounts to tire treads. Dual-sine tests on a nonlinear rubber indicate that for complex vibrations, consisting of many amplitudes and frequencies, the overall dynamic behavior will tend toward that obtained in single sine tests at a strain amplitude which corresponds to the largest amplitude that occurs in the time history. A similar conclusion is drawn from random vibration tests with a continuous spectrum of vibrations. The result of this is that under a more complex system of vibrations, nonlinear rubbers will behave in a more linear fashion and will exhibit higher damping than indicated by their dynamic properties measured in conventional sinusoidal tests. Therefore, when the service environment of many components is taken into account, the dynamic behavior of nonlinear rubbers may give better performance characteristics than expected from conventional testing.

Finite Element Model Updating of Space Grid Structures

2011 ◽  
Vol 243-249 ◽  
pp. 116-119
Author(s):  
Tian Yin Xiao ◽  
Jian Gang Han ◽  
Hong Bo Gao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Model Updating ◽  
Numerical Models ◽  
Time History ◽  
Element Model ◽  
Vibration Test ◽  
Modal Shape ◽  
Numerical Predictions ◽  
Space Grid

The aim of updating models is to generate improved numerical models which may be applied in order to predict actual dynamic behaviors of the structure. The approach of numerical predictions to the behavior of a physical system is limited by the assumptions used in the development of the mathematical model. Model updating is about correcting invalid assumptions by processing vibration test results. Updating by improving the physical meaning of the model requires the application of considerable physical insight in the choice of parameters to update and the arrangement of constraints, force inputs and response measurements in the vibration test. The choice of updating parameters is the most important and the numerical predictions should be sensitive to small changes in the parameters. So methods used in model updating places a demand that the mass, stiffness and damping terms should be based on physically meaningful parameters. Using the structure frequency and local modal shape acquired from structural time-history responses, a model updating method of space grid structures was established in this paper. A numerical example is provided to prove the accuracy of this method. The results show that the method can be effectively used to correct the finite element model of space grid structures.

scholarly journals Non-Destructive Tests for the Structural Assessment of a Historical Bridge over the Tua River

2013 ◽  
Vol 569-570 ◽  
pp. 390-397 ◽  
Author(s):  
Isabel Valente ◽  
Luís F. Ramos ◽  
Kevin Vasquez ◽  
Paulo Guimarães ◽  
Paulo B. Lourenço
Keyword(s):  
Failure Modes ◽  
Dynamic Testing ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Dynamic Test ◽  
Truss Structures ◽  
Design Standards ◽  
Element Analysis ◽  
Modern Design ◽  
Structural Assessment

Paradela Bridge is a metallic bridge located along the bank of the Tua River in northern Portugal. While the bridge is not currently in service, its structure is representative of many metallic truss structures built across the continent between the XIX and the XX century. Tua Line belongs to the Douro area that UNESCO recently declared as world heritage. This study acquires its importance since it might serve as an insight for the study of many other similar structures all over the country. This paper comprises a historic investigation of archived documents, an on-site survey to evaluate its present conditions, a dynamic testing and the construction and calibration of numerical models in finite element analysis (FEA) software, structural assessment and capacity rating estimation. The purpose of constructing numerical models was to evaluate the suitability of the bridge under the original loading and in accordance to modern design standards. The historical research revealed that the truss bridge was designed as a simply supported element and that a series of hand calculations were carried out on individual structural elements (e.g. main trusses, stringers and floor beams). Furthermore, a dynamic test was conducted in order to identify the global dynamic properties of the structure and to calibrate numerical models that ensure reliability and representativeness. FE models served through the structural assessment of the bridge in accordance with modern design codes and to estimate the safety of the bridge. Likewise, a nonlinear failure analysis was also conducted in order to estimate the capacity rate of the bridge and the likely failure modes.

Study on Seismic Performance of Archaized Steel Tower

2013 ◽  
Vol 438-439 ◽  
pp. 1524-1528
Author(s):  
Xiao Ke Li ◽  
Zhi Hao Wang ◽  
Jian Liu ◽  
Fu Li Song
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Seismic Performance ◽  
Dynamic Test ◽  
Time History ◽  
Element Model ◽  
Seismic Intensity ◽  
Natural Vibration Frequency ◽  
History Analysis ◽  
Seismic Behaviors

Combined with the design of Tiantang Site Protection Exhibition Project in Luoyang, China, the seismic performance of an archaized steel tower is studied in this paper. Firstly, a finite element model of whole structure is built accurately with ANSYS software. Then the dynamic behaviors of steel tower are analyzed. The natural vibration frequency and mode shape are obtained. Compared with dynamic test at site, the theoretical values are verified and it is reasonable about adopted loads and boundary conditions in the finite element model. After that, the seismic behaviors of steel tower are calculated and analyzed under seismic intensity 7 degree with methods of spectrum analysis and time-history analysis. The distribution characteristics of displacements and stresses are revealed. The results prove that the seismic performance of the given archaized steel tower can meet the code requirements. It is believed that the results in this paper would give some reference for the design of similar steel tower structures.

Response Law and Influencing Factors of the Soil under Action of Pile Driving Vibration Based on Midas/GTS

2013 ◽  
Vol 353-356 ◽  
pp. 979-983
Author(s):  
Dong Zhang ◽  
Jing Bo Su ◽  
Hui De Zhao ◽  
Hai Yan Wang
Keyword(s):  
Damping Ratio ◽  
Large Diameter ◽  
Time History ◽  
Pile Driving ◽  
Analysis Model ◽  
Vibration Load ◽  
History Analysis ◽  
Study Results ◽  
Propagation Law ◽  
Dynamic Time

Due to the upgrade and reconstruct of a high-piled wharf, the piling construction may cause the damage of the large diameter underground pipe of a power plant nearby. For this problem, a dynamic time-history analysis model was established using MIDAS/GTS program. Based on the analysis of the pile driving vibration and its propagation law, some parameters, such as the modulus of the soil, the Poissons ratio of soil, the action time of vibration load and the damping ratio of the soil that may have an effect on the response law of the soil, were studied. The study results not only serve as an important inference to the construction of this case, but also accumulate experience and data for other similar engineering practices.

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

Research on the Break Impact Test of Ultra High Voltage Composite Strain Insulator String

2013 ◽  
Vol 706-708 ◽  
pp. 1689-1692
Author(s):  
Cao Lan Liu ◽  
Bin Liu ◽  
Sheng Chun Liu ◽  
Zhen Liu ◽  
Kuan Jun Zhu
Keyword(s):  
Mechanical Properties ◽  
High Voltage ◽  
Impact Test ◽  
Test System ◽  
Dynamic Impact ◽  
Composite Insulator ◽  
Composite Strain ◽  
High Voltage Engineering ◽  
Dynamic Impact Factor ◽  
Ultra High Voltage

To guarantee the security of composite insulators as tension strings applied to ultra-high voltage engineering, it is necessary to study the mechanical properties of composite insulator regarding break impact. The test system was designed and the implementation plan was developed. Test was done to two insulator strings broken and the dynamic impact factor under different broken conditions at different tension was obtained accordingly, which provides reference and evidence for further study on mechanical properties of composite insulator and development of applicable design specifications.

Updating Finite Element Model of Combined Structures on the Basis of Dynamic Test Results

1996 ◽  
Author(s):  
Chen Xin ◽  
Qin Ye ◽  
Yuan Xiguang ◽  
Zhang Ping ◽  
Sun Jian
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Test Data ◽  
Dynamic Test ◽  
Element Model ◽  
Physical Parameters ◽  
Structural Joint ◽  
Combined Structure ◽  
Joint Parameters ◽  
Two Stages

Abstract According to the real situation, a new method of updating the finite element model (FEM) of a combined structure step by step is proposed in this paper. It is assumed that there are two types of error when establishing the FEMs. One of them results from the simplifications, in fact, it is severe for complicated structures, which usually assume many simplifications; the other is from the process of identifying structural joint parameters. For this reason, it is recommended that the FEM should be established in two stages. At the first stage, the local physical parameters relating with the simplifications are corrected by using the dynamic test data of the corresponding substructures. Then, the structural joint parameters that link the substructures are corrected by the dynamic test data of the combined structure as a whole. The updating formula is presented and proved, and its algorithm is also described. And the experimental results show that the efficiency and accuracy of the proposed method are quite satisfactory.

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