The mechanical properties of both asphalt concrete (AC) and soils are frequency-dependent. Chatti and Kim (1999) showed the effect of frequency-dependent AC layer properties on the horizontal strain and vertical deflections in pavements [1]. Moreover, the frequency dependence of soil damping has been taken into account by Hunt (1991) in developing the model of the transmission of traffic induced ground vibrations [2]. In this paper, in order to determine the frequency-dependent properties of AC and soft subgrade (SG), a backcalculation procedure is used which analyses results of nodestructive deflection tests (NDT) performed by a falling weight deflectometer (FWD). The method can evaluate pavement layer moduli, in the frequency range between 0.01 and 60 Hz, by considering the functional curves, reported by Sousa (1986), to describe the variation with frequency of the dynamic Young's and shear moduli (|E*| and |G*|), as well as the damping ratio of the AC [3]. Frequency domain velocities on pavement surface have been calculated using the SAPSI computer program with backcalculated frequency-dependent pavement layer moduli. Amplitude of frequency domain velocities calculated by the model have been compared with that calculated by the measured data. The results of a sensitivity analysis show the effect of AC layer thickness, Young's modulus, and pavement vibration responses. The results are not sensitive to variations in AC damping ratio.
The influence of Asphalt Pavement Layer Properties on Vibration Transmission
LOSA, MASSIMO
2002-01-01
Abstract
The mechanical properties of both asphalt concrete (AC) and soils are frequency-dependent. Chatti and Kim (1999) showed the effect of frequency-dependent AC layer properties on the horizontal strain and vertical deflections in pavements [1]. Moreover, the frequency dependence of soil damping has been taken into account by Hunt (1991) in developing the model of the transmission of traffic induced ground vibrations [2]. In this paper, in order to determine the frequency-dependent properties of AC and soft subgrade (SG), a backcalculation procedure is used which analyses results of nodestructive deflection tests (NDT) performed by a falling weight deflectometer (FWD). The method can evaluate pavement layer moduli, in the frequency range between 0.01 and 60 Hz, by considering the functional curves, reported by Sousa (1986), to describe the variation with frequency of the dynamic Young's and shear moduli (|E*| and |G*|), as well as the damping ratio of the AC [3]. Frequency domain velocities on pavement surface have been calculated using the SAPSI computer program with backcalculated frequency-dependent pavement layer moduli. Amplitude of frequency domain velocities calculated by the model have been compared with that calculated by the measured data. The results of a sensitivity analysis show the effect of AC layer thickness, Young's modulus, and pavement vibration responses. The results are not sensitive to variations in AC damping ratio.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
