Dynamic testing of a corrugated steel arch bridge

2008 ◽  
Vol 35 (3) ◽  
pp. 246-257 ◽  
Author(s):  
Zbigniew Manko ◽  
Damian Beben
Keyword(s):  
Vibration Frequency ◽  
Dynamic Load ◽  
Critical Speed ◽  
Dynamic Testing ◽  
The Other ◽  
Steel Plates ◽  
Highway Bridge ◽  
Dynamic Coefficients ◽  
Bridge Structures ◽  
Load Tests

The paper presents the results and conclusions of dynamic load tests that were conducted on a highway bridge over the Gimån River in Sweden made of Super Cor corrugated steel plates (CSP), the first bridge of this type in Scandinavia. The critical speed magnitudes, dynamic coefficients, velocity vibration, and vibration frequency are determined in the paper. Conclusions drawn from the tests can be most helpful in the assessment of the behaviour of this type of corrugated plate – soil bridge. In consideration of the application of this type of structure in the case of small-to-medium span bridges, the conclusions from this research cannot yet be generalized to all types of such solutions. The application details with respect to all types of such bridge structures would require additional analysis (field and model tests and calculations) on the other types of soil–steel bridges.

Analysis of Bridge Dynamic Load Tests

2012 ◽  
Vol 446-449 ◽  
pp. 1289-1292
Author(s):  
Jing Xi Chen ◽  
Tao Xia ◽  
Jun Huang ◽  
Guang Zhang
Keyword(s):  
Dynamic Load ◽  
Highway Bridge ◽  
The West ◽  
Advantages And Disadvantages ◽  
Its Analysis ◽  
Load Tests

This article is undertaken with the results of the detection of structural highway bridge in the west of Ezhou subsidiary line after completion and its analysis of completing and analyzing bridge dynamic Load Tests, in order to introduce three means of tests: the pulse tests, vehicle tests and bump tests. Finally we discuss the advantages and disadvantages, as well as the prospects.

Dynamic loading and testing of bridges in Ontario

1984 ◽  
Vol 11 (4) ◽  
pp. 833-843 ◽  
Author(s):  
J. R. Billing
Keyword(s):  
Dynamic Load ◽  
Dynamic Testing ◽  
Highway Bridge ◽  
Vibration Modes ◽  
Design Codes ◽  
Test Results ◽  
Design Code ◽  
Bridge Design ◽  
Strain Measurements ◽  
Bridge Testing

The Ontario Highway Bridge Design Code (OHBDC) contains provisions on dynamic load and vibration that are substantially different from other codes. Dynamic testing of 27 bridges of various configurations, of steel, timber, and concrete construction, and with spans from 5 to 122 m was therefore undertaken to obtain comprehensive data to support OHBDC provisions. Standardized instrumentation, data acquisition, and test and data processing procedures were used for all bridge tests. Data was gathered from passing trucks, and scheduled runs by test vehicles of various weights. Accelerometer responses were used to determine bridge vibration modes, and dynamic amplifications were obtained from displacement or strain measurements. The form of the provisions adopted for dynamic load and vibration was confirmed by the test results, subject to minor adjustment of values. Observations on the distribution of dynamic load, and its relationship to span length and vehicle weight, may provide a basis for future refinement of the dynamic load provisions. If the stiffness of curbs and barrier walls is not included in deflection calculations, bridges designed by deflection could be penalized. Key words: bridges, vibration, bridge testing, bridge design codes.

Assessing ballast cleaning as a rehabilitation method for railway masonry arch bridges by dynamic load tests

2017 ◽  
Vol 232 (4) ◽  
pp. 1135-1148 ◽  
Author(s):  
Saeed Mohammadzadeh ◽  
Amin Miri ◽  
Mehrdad Nouri
Keyword(s):  
Dynamic Load ◽  
Structural Changes ◽  
Dynamic Testing ◽  
Load Testing ◽  
Test Results ◽  
Masonry Arch ◽  
Rehabilitation Programs ◽  
Before And After ◽  
Load Tests ◽  
Arch Bridges

Dynamic load testing has become a common practice for condition assessment of masonry arch bridges and lays the foundation for their rehabilitation procedures; however, additional dynamic testing after rehabilitation is rare. Carrying out dynamic load tests before and after rehabilitation programs produces valuable results with regard to the structural changes of the bridge. This paper tries to assess the effects of ballast cleaning on the performance of railway masonry arch bridges by conducting dynamic load tests before and after the rehabilitation procedure. To do so, a 70-year-old masonry arch bridge is instrumented with deflection meters and accelerometers. Dynamic load tests are carried out before and after ballast cleaning and results are compared. According to the test results, vertical deflections of different spots on the bridge remain the same, with a deviation of less than 5%. On the other hand, vibrations on the structure are reduced significantly. On average, vibration levels are reduced by 35% in different spots of the structure.

Feasibility investigation of a compressor rotor supported by gas foil bearings with inhomogeneous bump foils

2021 ◽  
pp. 135065012110046
Author(s):  
Hao Li ◽  
Haipeng Geng ◽  
Bo Wang ◽  
Wei Zheng
Keyword(s):  
Critical Speed ◽  
Rotor System ◽  
Experimental Result ◽  
Test Results ◽  
Rotating Speed ◽  
Foil Bearings ◽  
Dynamic Coefficients ◽  
High Order Harmonic ◽  
Compressor Rotor ◽  
Operating Points

In this paper, a rotordynamic experiment on a compressor rotor system is presented and the feasibility of gas foil bearings with inhomogeneous bump foils is verified. A push–pull device is designed to obtain the stiffness curve and the nominal clearance of foil bearings. Operating points and dynamic coefficients of the rotor system at each rotating speed are predicted. In rotordynamic analysis, an alternative model of the impeller is proposed and the critical speed is predicted by employing the finite element method, in which the dynamic coefficients of inhomogeneous foil bearings are taken into account. Compared with the experimental result, the accuracy of the prediction for the critical speed is verified to be about 14% error. Two sets of foil bearings with 22 and 41 μm nominal clearance are manufactured and tested. Test results indicate that the vibration amplitude can be greatly reduced by diminishing the bearing clearance. When foil bearings with 22 μm clearance are used, the high-order harmonic frequencies of rotor vibration are significantly inhibited, and the amplitude of the rotating frequency is obviously restricted. Thus, the foil bearing with inhomogeneous bump foils tested in this paper can meet the speed requirement of the compressor when the nominal clearance is set at 22 μm.

Design and structural performance measurements of a novel multi-cantilever foil bearing

2014 ◽  
Vol 229 (10) ◽  
pp. 1830-1838 ◽  
Author(s):  
Kai Feng ◽  
Xueyuan Zhao ◽  
Zhiyang Guo
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Foil Bearing ◽  
Load Tests ◽  
Stiffness And Damping ◽  
Motion Amplitude

With increasing need for high-speed, high-temperature, and oil-free turbomachinery, gas foil bearings (GFBs) have been considered to be the best substitutes for traditional oil-lubricated bearings. A multi-cantilever foil bearing (MCFB), a novel GFB with multi-cantilever foil strips serving as the compliant underlying structure, was designed, fabricated, and tested. A series of static and dynamic load tests were conducted to measure the structural stiffness and equivalent viscous damping of the prototype MCFB. Experiments of static load versus deflection showed that the proposed bearing has a large mechanical energy dissipation capability and a pronounced nonlinear static stiffness that can prevents overly large motion amplitude of journal. Dynamic load tests evaluated the influence of motion amplitude, loading orientation and misalignment on the dynamic stiffness and equivalent viscous damping with respect to excitation frequency. The test results demonstrated that the dynamic stiffness and damping are strongly dependent on the excitation frequency. Three motion amplitudes were applied to the bearing housing to investigate the effects of motion amplitude on the dynamic characteristics. It is noted that the bearing dynamic stiffness and damping decreases with incrementally increasing motion amplitudes. A high level of misalignment can lead to larger static and dynamic bearing stiffness as well as to larger equivalent viscous damping. With dynamic loads applied to two orientations in the bearing midplane separately, the dynamic stiffness increases rapidly and the equivalent viscous damping declines slightly. These results indicate that the loading orientation is a non-negligible factor on the dynamic characteristics of MCFBs.

Driven cast-in-situ pile capacity: insights from dynamic and static load testing

2021 ◽  
Author(s):  
Kevin N. Flynn ◽  
Bryan A. McCabe
Keyword(s):  
Dynamic Load ◽  
Shear Stresses ◽  
Load Testing ◽  
Pile Capacity ◽  
Compression Load ◽  
Shaft Resistance ◽  
Pile Installation ◽  
Cast Concrete ◽  
Load Tests

Driven cast-in-situ (DCIS) piles are classified as large displacement piles. However, the use of an oversized driving shoe introduces additional complexities influencing shaft resistance mobilisation, over and above those applicable to preformed displacement piles. Therefore, several design codes restrict the magnitude of shaft resistance in DCIS pile design. In this paper, a series of dynamic load tests was performed on the temporary steel driving tubes during DCIS pile installation at three UK sites. The instrumented piles were subsequently subjected to maintained compression load tests to failure. The mobilised shear stresses inferred from the dynamic tests during driving were two to five times smaller than those on the as-constructed piles during maintained load testing. This was attributed to soil loosening along the tube shaft arising from the oversized base shoe. Nevertheless, the radial stress reductions appear to be reversible by the freshly-cast concrete fluid pressures which provide lower-bound estimates of radial total stress inferred from the measured shear stresses during static loading. This recovery in shaft resistance is not recognised in some European design practices, resulting in conservative design lengths. Whilst the shaft resistance of DCIS piles was underpredicted by the dynamic load tests, reasonable estimates of base resistance were obtained.

Dynamic Performance Analysis on High-Speed Railway Continuous Girder Bridge

2011 ◽  
Vol 280 ◽  
pp. 186-190
Author(s):  
Shou Tan Song ◽  
Ji Wen Zhang ◽  
Xin Yuan
Keyword(s):  
High Speed ◽  
Moving Load ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Wheel Load ◽  
Dynamic Coefficients ◽  
Bridge Structures ◽  
Continuous Girder Bridge ◽  
Girder Bridge ◽  
Dynamic Performance Analysis

The dynamic performance of continuous girder under the train in a series of speed is studied through examples, and the main conclusions are given in the following. The resonance mechanism of continuous girder is similar to simply supported beam. The vehicle wheel load forms regular moving load series, which induces periodical action and resonance of the bridge. The damping ratio of bridge itself has less effect on the amplitude at the loading stage, but significant effects appear when the load departs from the bridge. The count of continuous spans also has less impact on the dynamic coefficients, so three continuous spans can be adopted for calculation and analysis. Span and fundamental frequency have significant influence on dynamic coefficients of bridge structures. To extend the span of the bridge structure can reduce the dynamic coefficient while keeping its frequency invariant. The fundamental frequencies of different bridges are corresponding to certain resonant speeds, which calls for the attention in the design.

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