Skip to main content
SpringerLink
Log in

Thermal Influence on Long-Distance Optical Measurement of Suspension Bridge Displacement

  • Published:
International Journal of Thermophysics Aims and scope Submit manuscript

Abstract

This paper discusses the thermal influence on long-distance and noncontact measurement of suspension bridge three-dimensional displacement by the use of an optical system composed of a digital camera, infrared active targets, and computational support. In this type of measurement method, the optical propagation path of light through the air can range from 250 m up to 750 m, making its measurement accuracy strongly dependent on atmospheric refraction and turbulence, phenomena that are linked to the vertical temperature gradient between the camera and targets. In addition, the adopted measurement geometrical configuration can lead to a height difference between these two elements (camera and targets) above 50 m. The paper describes the experimental setup and procedure followed for the determination of local temperature vertical gradients in the 25th of April Bridge in Lisbon (Portugal), where an optical measurement system was applied. The obtained thermal measurements are presented and applied in the evaluation of the systematic refraction vertical deviation, based on appropriate mathematical models mentioned in the paper, and for the identification of stable or unstable observation thermal conditions related to turbulence.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

Notes

  1. In the applied optical approach, the digital camera is rigidly installed in the bridge’s central section of its main span, orientated toward the tower foundation where a set of four active targets with known coordinates is installed. Changes in the camera’s projection center position are considered representative of the bridge’s displacement, being determined by the knowledge of the camera’s intrinsic parameters and targets image and world coordinates by a nonlinear optimization procedure.

  2. Horizontal pressure gradients (wind) can also lightly increase the atmospheric turbulence by contributing to the mixture of different warm or cold air layers. In a radiometric perspective, turbulence can also be caused by partial coherence of the observed light source.

References

  1. Y. Qiao, Acta Opt. Sin. 4, 984 (1984)

    Google Scholar 

  2. J. Casaca, Atmospheric Refraction in Applied Geodesy (LNEC, Lisbon, 2004)

    Google Scholar 

  3. M. Aikawa, T. Hiraki, Meteorol. Atmos. Phys. 104, 95 (2009)

    Article  ADS  Google Scholar 

  4. P.E. Ciddor, Appl. Opt. 35, 1566 (1996)

    Article  ADS  Google Scholar 

  5. A. Picard, R.S. Davis, M. Gläser, K. Fujii, Metrologia 45, 149 (2008)

    Article  ADS  Google Scholar 

  6. G.A. Kharaghani, Propagation on Refraction Errors in Trigonometric Height Traversing and Geodetic Levelling, M.Sc. Thesis, Technical Report No. 132, University of New Brunswick, 1987, pp. 6–19

  7. E.K. Webb, Temperature and Humidity Structure in the Lower Atmosphere in Geodetic Refraction (Springer, Berlin, 1984)

    Google Scholar 

Download references

Acknowledgments

The authors gratefully acknowledge the company EP—Estradas de Portugal, S.A. who authorized and supported the experimental work performed on the 25th of April Bridge and to the Colleagues of the Scientific Instrumentation Centre of LNEC that provided experimental assemblies and technical support. The anemometers used in the experimental work were gently provided by Dr. Marques da Silva from LNEC’s Aerodynamic Sector. The author L. Lages Martins also acknowledges the award of a joint doctoral scholarship from the FCT—Fundação para a Ciência e a Tecnologia, I.P. and LNEC—Laboratório Nacional de Engenharia Civil, I.P.

Author information

Authors and Affiliations

  1. Scientific Instrumentation Center, National Laboratory for Civil Engineering, Lisbon, Portugal

    Luís Lages Martins & Álvaro Silva Ribeiro

  2. Laboratory of Optics, Lasers and Systems, Faculty of Sciences, University of Lisbon, Lisbon, Portugal

    José Manuel Nunes Vicente Rebordão

Authors
  1. Luís Lages Martins
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. José Manuel Nunes Vicente Rebordão
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Álvaro Silva Ribeiro
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Luís Lages Martins.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Lages Martins, L., Nunes Vicente Rebordão, J.M. & Silva Ribeiro, Á. Thermal Influence on Long-Distance Optical Measurement of Suspension Bridge Displacement. Int J Thermophys 35, 693–711 (2014). https://doi.org/10.1007/s10765-014-1607-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10765-014-1607-3

Keywords

Search

Navigation