Road Pavement Stiffness Determination using SASW Method

  • M. A. Ismail
  • A. R. Samsudin
  • A. G. Rafek
  • K. A. M. Nayan



The Spectral Analysis of Surface Waves (SASW) method is an in-situ seismic technique for the evaluation and assessment of road pavement. The method is based on the theory of stress waves propagating in elastic media with the key elements being the generation and detection of Rayleigh wave motion. A set of transient impact source with a range of frequencies is used to generate the Rayleigh wave energy that is able to propagate along the surface layer of the pavement. Through two vertical accelerometers, the motion of the wave for each range of frequency is recorded and calculated using a dynamic signal analyzer. A dispersion curve is then constructed from the cross-power spectrum of the Fast Fourier Transform (FFT) that results in the phase velocity versus wavelength plot. An iterative inversion is then carried out to obtain the shear wave velocity profile with depth and the corresponding dynamic modulus of each pavement units. This paper presents a case study carried out on a new road pavement construction site. It was found that the profile of the dynamic shear and Young’s modulus versus depth obtained from SASW method


Al-Hunaidi, M.O., 1998. Evaluation-based genetic algorithms for analysis of non-destructive surface waves test on pavements, NDT&E international, Vol.31, No.4, pp.273-280.

Cho, Y.S. and Lin, F-B, 2001. Spectral analysis of surface wave response of multi-layer thin cement mortar slab structure with finite element thickness, ND&T E International 34 (2001), Elsevier Science, pp.115-122.

Cho, Y.S., 2002, NDT response of spectral analysis of surface wave method to multi-layer thin high strength concrete structure, Ultrasonic, 2336, Elsevier Sciences.

Gucunski, N., 2000. Field Implementation of Surface Waves for Obstacle Detection (SWOD) Method. 15th WCNDT, Roma 2000.

Hossain, M.M., and Drnevich, V.P., 1989. Numerical and optimisation techniques applied to surface waves for back-calculation of layer moduli. In Non-destructive testing of pavements dan back-calculation of moduli. Edited by Bush, A.J., III, dan Baladi, G.Y. American Society for Testing dan Materials, Special Technical Publication 1026, pp. 649-669.

Joh, S.-H., 1996. Advances in data interpretation technique for Spectral Analysis-of-Surface-Waves (SASW) measurements. Ph.D. Dissertation, the University of Texas at Austin, Austin, Texas, U.S.A., 240 pp.

Jones, R.B. 1958. In-situ measurement of the dynamic properties of soil by vibration methods. Geotechnique. Vol.8.(1).pp.1-21.

Kausel, E., and Röesset, J.M., 1981. Stiffness matrices for layered soils. Bull. Seismol. Soc. Am., 72, pp 1743-1761.

Kim, D.S, Shin M.K and Park H.C., 2001. Evaluation of density in layer compaction using SASW method. Soil Dynamic and Earthquake Engineering 21 (2001), Elsevier Science, pp.39-46.

Madshus, C., and Westerdahl, H., 1990. Surface wave measurements for construction control and maintenance planning of roads and airfields. Proc. 3rd. Int. Conf. On Bearing Capacity of Roads and Airfields, July 3-5, Trondheim, Norway.

Nazarian, S., 1984. In-situ determination of elastic moduli of soil deposits and pavement systems by Spectral-Analysis-Of-Surface-Wave Method. Ph.D. Dissertation, University of Texas at Austin, 452 pp.

Nazarian, S. and Stokoe II, K. H. 1984. In-situ shear wave velocity from spectral analysis of surface waves. Proc. 8th World Conf. On Earthquake Engineering, 3, pp 31-38.

Rix, G.J., Bay, J.A, and Stokoe II, K.H., 1990. Assessing in situ stiffness of curing Portland cement concrete with seismic tests. Paper presented to Annual Meeting, Transportation Research Board, Washington, D.C., January.

Stokoe II, K.H., Wright, S.G., Bay, J.A, and Roesset, J.M., 1994. Characterization of geotechnical sites by SASW method. Geotechnical characterization of sites, R.D. Wood, ed., Oxford and IBH Publishing Co., New Delhi, India, 15-26.

Stokoe II, K.H. and Hoar, J.H.. 1978. Variable affecting in situ seismic measurement. Proc. Conference on Earthquake Engineering and Soil Dynamic, ASCE, Pasadena, CA., Vol.II,pp.919-939.

Thomson, W.T. 1950. Transmission of elastic waves through a stratified solid medium. Jour. of Appl. Phys., Vol. 21, Feb. 1950, pp 89-93.

William, O. 1981. Rayleigh wave velocity measurement using broad band frequency sources, Miscellaneous Paper EL-81-3, US Army Engineer Waterways Experiment Station, Vicksburg.

Yoder, E.J. and Witczak, M.W, 1975. Principle of pavement design. John Willey & Sons, New York.

Zagyapan, M. and Fairfield, C.A., 2002. Continuous surface wave and impact methods of measuring the stiffness and density of railway ballast, NDT&E International 35 (2002), Elsevier Science, pp.75-81.

How to Cite
Ismail, M. A., Samsudin, A. R., Rafek, A. G., & Nayan, K. A. M. (2012). Road Pavement Stiffness Determination using SASW Method. Journal of Civil Engineering, Science and Technology, 3, 9-16.