An Improved Technique for Transforming the Energy Vibrations of Traffic into Vertical Displacements

This work presents a proposal to improve a previous procedure to transform the energetic vibrations recorded by geophones and accelerometers into vertical displacements (or deflections) on the surface of the pavement structure. The procedure includes the study of the response obtained from laboratory-scale tests performed on a vibrating table and from full-scale tests performed with the Gustave Eiffel University fatigue carousel and a section instrumented in situ. The results show that at low frequencies, the signals obtained with geophones and accelerometers during roadway monitoring require specific treatment. First, the entire sensitivity transfer function must be used to transform the electrical voltage values into velocity or acceleration and finally by single or double integration into vertical displacements. Second, the amplification factors (AFs) dependent on the test speed must be applied to obtain the correct vertical displacement magnitudes compared to reference sensors (laser and anchored deflection sensors).