Model studies of barrier performance in the presence of ground surfaces. Part II—Different shapes

Abstract

Modeling experiments are reported which have investigated the frequency dependence of barrier insertion loss for various noise barrier designs. The effect of ground surfaces has been studied, treating both grass-covered ground and asphalt. Reshits show that interference effects are an important feature of observed behavior. Use is made of this knowledge in the design and testing of new barrier designs, which deliberately introduce a beneficial destructive interference phenomenon to increase insertion losses over well-defined ranges of frequency.

On the choice between walls and berms for road traffic noise shielding including wind effects

“…This is consistent with earlier findings reported in the work of Hutchins et al (1984b) and Busch et al (2003). The differences amount up to 1.7 dBA when comparing berm 4 to berm 3 at 130 km/h (both vehicle types, all receiver zones).…”

“…Kotzen and English, 2009). This lower shielding can however be compensated by placing a small screen on top of the berm, or by constructing berms with flat tops (Hutchins et al, 1984b). …”

Using natural means to reduce surface transport noise during propagation outdoors

“…Typical advice from earlier work [35] is to make an earth berm slightly higher than a straight noise wall to achieve comparable noise reduction (to compensate for the fact that the greatest height of a berm is reached somewhat further away from the road). Hutchins et al [36] proposed, as an alternative, to place a small screen on top of the berm, or to construct a flat-topped berm. Busch et al [37] stressed the importance of the acoustical properties of the material constituting the berm.…”

Scattering by a cylinder covered with an arbitrary distribution of impedance and application to the optimization of a tramway noise abatement system

“…This approach could also be considered as an extreme case scenario, since a softer ground like grass would probably attenuate the noise more, but may also reduce the improvement of the attenuation due to the barrier as suggested by Hutchins et al [21]. This would also require further investigation.…”

“…(20), and then using the relationship (21) to compute the remaining components of the gradient. Once the total gradient is known, one can compute the derivative of p sc 1 and p sc 2 , and finally that of the attenuation by using the correct component of the gradient.…”