The performance of t-profile and associated noise barriers

Performance of profiled single noise barriers covered with quadratic residue diffusers

“…The performance of noise barriers with different top profiles has been investigated by many researchers. Hothersall et al [1] reviewed the works done on barriers with caps having T, Y, and arrow profiles. Crombie et al [2] introduced multiple-edge noise barriers, which could increase their efficiency in the deep shadow zone.…”

Performance of Traffic Noise Barriers with Varying Cross-Section

“…If we assume that the sound pressure in each point of space depends harmonically on time, then the sound pressure is given by (5), where x, y and z are Cartesian coordinates of the imission point. In order to obtain the sound pressure value in that point, a solution to the homogenous Helmholtz equation given by (6) has to be found, where / k c 2 r m = = is the wave number (rad/m), c is the speed of sound (m/s), m is the wavelength (m).…”

“…For barriers with a complex shape, where no analytical method can be used, Seznec [3] proposed the development of a program that uses numerical calculation with boundary elements (Boundary Element Method, BEM). Hothersall et al [4,5] studied a number of barriers by comparing the plain barrier with barriers that had a special circular, Y-or T-shaped element installed on the top. The Y-and T-shaped elements have proven to work very well for sound diffusion.…”

Fuzzy TOPSIS Approach in Selection of Optimal Noise Barrier for Traffic Noise Abatement

“…Noise measurements with a 4 m highway noise barrier with a horizontal cap of 0.75 m (T-profile) in Toronto produced a noise reduction of 1-1.5 dB greater than that obtained for the same barrier without the cap (May, Osman, 1980). In a review of the barrier studies involving T-, Y-, and arrow profile noise barriers, numerical modelling and boundary element approach, Hothersall et al(1991) had concluded that for barriers with reflecting surfaces, the changes in insertion losses for various profiles can be described by using the concept of path difference. Further the introduction of absorptive upper surfaces produces a significant increase in insertion loss.…”

“…The above studies generally include experimental, theoretical, and numerical analyses with an objective of predicting the barrier insertion loss in laboratory and free field conditions. The addition of a horizontal cap to a conventional barrier thus creating a T-profile has been discussed in various studies and in most conditions; it has been observed that Y-and arrow profiles perform less efficiently than the T-profile barrier (Hothersall et al, 1991). Design considerations for erection of noise barriers of optimum dimensions providing a high insertion loss are essential and depend upon site and situation.…”