Testing Bridges by Using Tiltmeter Measurements

2000 ◽  
Vol 1696 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Ahmet K. Sanli ◽  
Erdogan A. Uzgider ◽  
Ozden B. Caglayan ◽  
Kadir Ozakgul ◽  
Jan Bien
Keyword(s):  
Numerical Procedure ◽  
High Sensitivity ◽  
Structural Testing ◽  
Evaluation Procedure ◽  
Strong Wind ◽  
Bridge Structures ◽  
Vertical Displacements ◽  
Load Tests ◽  
Stiffness Characteristics ◽  
Displacement Transducers

An efficient numerical procedure based on the cubic spline technique is developed to obtain the vertical displacements of the bridge deck using the slope values measured at selected points under the test loading. Most static load tests of bridges are performed to evaluate the stiffness characteristics of bridge structures or to check the accuracy of their computer models. From this standpoint, vertical displacements of the bridge under certain loads have a crucial importance. However, if the bridge is over a river, a lake, muddy ground, or a major highway, conventional displacement transducers cannot be used appropriately for this purpose. Furthermore, strong wind and the bridge’s height badly affect the accuracy of the transducers. Another way to obtain bridge deflection is to use an indirect method. Tiltmeters, which have been increasingly used for construction monitoring and structural testing of bridges, are suitable devices in terms of indirect deflection measurements because of their characteristics such as high sensitivity, easy installation, and small electrical drift. The testing and evaluation procedure developed was applied on a real bridge, and the results indicated that this method could be applied to obtain vertical displacements of bridges as an alternative to the use of conventional displacement transducers.

High-sensitivity displacement transducers in control and measuring equipment

1980 ◽  
Vol 23 (8) ◽  
pp. 697-702
Author(s):  
V. V. Kozlov ◽  
V. P. Sokolov ◽  
Yu. K. Zavodov
Keyword(s):  
Measuring Equipment ◽  
High Sensitivity ◽  
Displacement Transducers

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.

Optical Measuring Technique for the Investigation of Built-Up Cold-Formed Steel Structural Members

2011 ◽  
Vol 473 ◽  
pp. 343-351 ◽  
Author(s):  
Iveta Georgieva ◽  
Luc Schueremans ◽  
Guido De Roeck ◽  
Lincy Pyl
Keyword(s):  
Local Buckling ◽  
Structural Members ◽  
Distortional Buckling ◽  
Residential Housing ◽  
3D Motion Analysis ◽  
Vertical Displacements ◽  
Global Buckling ◽  
Cold Formed Steel ◽  
Thin Walled ◽  
Displacement Transducers

The construction industry uses cold-formed steel (CFS) sheets in the form of galvanised thin-walled profiles and corrugated sheets. In the past decade, CFS profiles have been competing with their hot-rolled counterparts as primary structural members of industrial halls, office buildings and residential housing of up to 3-4 storeys. The spans and column heights achieved with CFS profiles are ever larger. Due to the large slenderness of these members, adequate strength and stability are necessary, as well as reliability in design. Thin-walled members go through buckling during all stages of their working life. Local buckling appears at loads sometimes much lower than the design load. Distortional buckling seriously reduces the member resistance. It interacts with warping and lateral-torsional buckling, being significant for these asymmetric open sections. To restrict these effects, builders employ double sections - usually two standard cold-formed shapes bolted together to form a built-up section. These sections have the advantages of symmetry, higher stability and strength. The design of built-up members involves many uncertainties - although the European standard includes guidelines on the prediction of local, distortional and global buckling, the partial integrity and interaction between the parts of the composed members is still not studied. To study the actual behaviour, built-up members are tested in bending. An optical device for 3D motion analysis measures the displacement of points of interest on the specimen. Two interacting cameras use parallax to obtain the position of an arbitrary number of reflective markers glued to the specimen. The device tracks the movement of the markers in a 3D coordinate system without any contact with the specimen. Standard displacement transducers measure vertical displacements to validate the results. The paper gives an appraisal of the applicability of the method, a summary of the difficulties faced and the outcome of the test campaign.

scholarly journals Vertical Displacements Measuring Methods During Bridge Load Tests

2016 ◽  
Vol 73 ◽  
pp. 01014 ◽  
Author(s):  
Boštjan Kovačič ◽  
Ante Marendić ◽  
Rok Kamnik ◽  
Mikhail Volkov ◽  
Vera Roy
Keyword(s):  
Measuring Methods ◽  
Vertical Displacements ◽  
Load Tests

scholarly journals Experimental evaluation of the interaction between strength concrete block walls under vertical loads

2016 ◽  
Vol 9 (5) ◽  
pp. 643-681 ◽  
Author(s):  
L. O. CASTRO ◽  
R. C. S. S. ALVARENGA ◽  
R. M. SILVA ◽  
J. C. L. RIBEIRO
Keyword(s):  
High Performance ◽  
Load Transfer ◽  
High Performance Concrete ◽  
Concrete Block ◽  
Load Rate ◽  
Service Load ◽  
Vertical Displacements ◽  
Concrete Blocks ◽  
Central Support ◽  
Displacement Transducers

Abstract This paper aims to evaluate the interaction between structural masonry walls made of high performance concrete blocks, under vertical loads. Two H-shaped flanged wall series, all full scale and using direct bond, have been analyzed experimentally. In one series, three flanged-walls were built with the central wall (web) supported and, in the other one, three specimens were built without any support at the central web. The load was applied on the central wall and vertical displacements were measured by means of displacement transducers located at eighteen points in the wall-assemblages. The results showed that the estimated load values for the flanges were close to those supported by the walls without central support, where 100% of the load transfer to the flanges occur. The average transfer load rate calculated based on the deformation ratio in the upper and lower section of the flanged-walls, with the central web support, were 37.65% and 77.30%, respectively, showing that there is load transfer from the central wall (web) toward the flanges, particularly in the lower part of the flanged walls. Thus, there is indication that the distribution of vertical loads may be considered for projects of buildings for service load, such as in the method of isolated walls group. For estimation of the failure load, the method that considers the walls acting independently showed better results, due to the fact that failure started at the top of the central wall, where there is no effect of load distribution from the adjacent walls.

Geodetic Measurement of Vertical Displacements (Illustrated with the Slovenian Viaduct)

2015 ◽  
Vol 725-726 ◽  
pp. 913-921 ◽  
Author(s):  
Boštjan Kovačič ◽  
Rok Kamnik ◽  
Nikolay Vatin
Keyword(s):  
Laser Scanning ◽  
Load Test ◽  
Field Observations ◽  
Geodetic Measurement ◽  
Basic Goal ◽  
Vertical Displacements ◽  
Analysis Of Results ◽  
Load Tests ◽  
Geometric Changes ◽  
Displacement Measurements

Today there are a lot of sophisticated methods to measure and analyse a bridge during load tests as a GPS, photogrammetric measurements, laser scanning, etc., The use of an classical techniques as trigonometric hights is still good enough for most demanding field observations. In practice control measurements are performed with the help of geodetic measurements, of which the basic goal is to capture any geometric changes in the measured object, or its displacements and deformations are found. In this article the use of trigonometric hights during a load test on the biggest Slovenian viaduct “Črni Kal” is introduced, displacement measurements on the viaduct and an analysis of results, with particular stress on the accuracy of the calculations.

Three-Dimensional Navier–Stokes Computation of Turbomachinery Flows Using an Explicit Numerical Procedure and a Coupled k–ε Turbulence Model

1992 ◽  
Vol 114 (3) ◽  
pp. 627-642 ◽  
Author(s):  
R. F. Kunz ◽  
B. Lakshminarayana
Keyword(s):  
Reynolds Number ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Secondary Flows ◽  
Quality Data ◽  
Navier Stokes ◽  
Evaluation Procedure ◽  
Pressure Probe ◽  
Time Step

An explicit, three-dimensional, coupled Navier–Stokes/k–ε technique has been developed and successfully applied to complex internal flow calculations. Several features of the procedure, which enable convergent and accurate calculation of high Reynolds number two-dimensional cascade flows, have been extended to three dimensions, including a low Reynolds number compressible form of the k–ε turbulence model, local time-step specification based on hyperbolic and parabolic stability requirements, and eigenvalue and local velocity scaling of artificial dissipation operators. A flux evaluation procedure, which eliminates the finite difference metric singularity at leading and trailing edges on H- and C-grids, is presented. The code is used to predict the pressure distribution, primary velocity, and secondary flows in an incompressible, turbulent curved duct flow for which CFD validation quality data are available. Also, a subsonic compressor rotor passage, for which detailed laser, rotating hot-wire, and five-hole pressure probe measurements have been made is computed. Detailed comparisons between predicted and measured core flow and near-wall velocity profiles, wake profiles, and spanwise mixing effects downstream of the rotor passage are presented for this case. It is found that the technique provides accurate and convergent engineering simulation of these complex turbulent flows.

Three-Dimensional Navier-Stokes Computation of Turbomachinery Flows Using an Explicit Numerical Procedure and a Coupled k-ε Turbulence Model

1991 ◽  
Author(s):  
R. F. Kunz ◽  
B. Lakshminarayana
Keyword(s):  
Reynolds Number ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Secondary Flows ◽  
Three Dimensions ◽  
Quality Data ◽  
Navier Stokes ◽  
Evaluation Procedure ◽  
Pressure Probe

An explicit, three-dimensional, coupled Navier-Stokes/k-ε technique has been developed and successfully applied to complex internal flow calculations. Several features of the procedure, which enable convergent and accurate calculation of high Reynolds number two-dimensional cascade flows have been extended to three-dimensions, including a low Reynolds number compressible form of the k-ε turbulence model, local timestep specification based on hyperbolic and parabolic stability requirements, and eigenvalue and local velocity scaling of artificial dissipation operators. A flux evaluation procedure which eliminates the finite difference metric singularity, at leading and trailing edges, on H- and C-grids, is presented. The code is used to predict the pressure distribution, primary velocity and secondary flows in an incompressible, turbulent curved duct flow for which CFD validation quality data is available. Also, a subsonic compressor rotor passage, for which detailed laser, rotating hot-wire and five-hole pressure probe measurements have been made is computed. Detailed comparisons between predicted and measured core flow and near wall velocity profiles, wake profiles, and spanwise mixing effects downstream of the rotor passage are presented for this case. It is found that the technique provides accurate and convergent engineering simulation of these complex turbulent flows.

scholarly journals REDUCTION OF UNCERTAINTIES IN LASER STRIPE MEASUREMENT OF SOLID PARTICLES CONCENTRATION

2018 ◽  
Vol 58 (3) ◽  
pp. 171 ◽  
Author(s):  
Jan Krupička ◽  
Tomáš Picek ◽  
Štěpán Zrostlík
Keyword(s):  
Laser Sheet ◽  
High Sensitivity ◽  
Suspended Particles ◽  
Solid Particles ◽  
Evaluation Procedure ◽  
Local Concentration ◽  
Measured Concentration ◽  
Laser Stripe ◽  
Two Peaks

Laser stripe measurement (LSM) is a relatively novel method for measuring a local concentration of coarse particles in a mixture with fluid. It is based on an analysis of camera records of the laser sheet penetration in to the mixture. We report on our measurements of the concentration of suspended particles in a fluidization cell and focus on the parameters affecting the evaluation procedure for the measured data. A high sensitivity of the measured concentration to the correction for the position of the wall and to the threshold brightness for data filtering is demonstrated. The uncertainty in the wall position is reduced by applying a rectification procedure based on an identification of the position of a laser stripe drawn at the wall of the fluidization cell. The main motivation for the presented study was to find guidelines for the determination of the threshold brightness, absence of which can be considered a serious weakness of the LSM when particles of non-ideal optical properties are tested. Histograms of the brightness of laser stripes drawn on a surface of suspended particles are analysed with the aim to find a connection between the histograms and the threshold brightness. The threshold brightness is shown to be proportional to a position of the second of the two peaks identified in a histogram. Based on the results of the analysis, a method is proposed for the determination of the threshold brightness.

scholarly journals Nondestructive Damage Assessment of Composite Structures Based on Wavelet Analysis of Modal Curvatures: State-of-the-Art Review and Description of Wavelet-Based Damage Assessment Benchmark

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Andrzej Katunin
Keyword(s):  
Wavelet Analysis ◽  
Wavelet Transforms ◽  
Damage Assessment ◽  
Composite Structures ◽  
Structural Damage ◽  
Early Stage ◽  
Measurement Data ◽  
High Sensitivity ◽  
Structural Testing ◽  
Operational Conditions

The application of composite structures as elements of machines and vehicles working under various operational conditions causes degradation and occurrence of damage. Considering that composites are often used for responsible elements, for example, parts of aircrafts and other vehicles, it is extremely important to maintain them properly and detect, localize, and identify the damage occurring during their operation in possible early stage of its development. From a great variety of nondestructive testing methods developed to date, the vibration-based methods seem to be ones of the least expensive and simultaneously effective with appropriate processing of measurement data. Over the last decades a great popularity of vibration-based structural testing has been gained by wavelet analysis due to its high sensitivity to a damage. This paper presents an overview of results of numerous researchers working in the area of vibration-based damage assessment supported by the wavelet analysis and the detailed description of the Wavelet-based Structural Damage Assessment (WavStructDamAs) Benchmark, which summarizes the author’s 5-year research in this area. The benchmark covers example problems of damage identification in various composite structures with various damage types using numerous wavelet transforms and supporting tools. The benchmark is openly available and allows performing the analysis on the example problems as well as on its own problems using available analysis tools.

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