A study of measurements and countermeasures for low-frequency noise caused by expressway bridges

Abstract

Expressway bridges, though rarely, generate low-frequency noise caused by coupled bridge and road traffic vibration. This paper reports a case study on taking measurements and countermeasures of infrasound on an actual expressway bridge. First, the paper outlines a wind noise estimation method that takes into account the effect of wind and reflects the frequency, mean velocity, and turbulence intensity on the measurements of infrasound. Next, a case study on an improved TMD (Tuned Mass Damper), one method to suppress low-frequency noise, is presented. An overview of the generator-type TMD, in which the oil damper of the TMD is replaced by a linear generator, is given, and the results of a field test of its effectiveness are reported. The damping function of the generator-type TMD can be easily tuned by incorporating a variable resistance value into the generator. Through these undertakings, energy from road traffic vibration can be effectively utilized, supporting reductions in environmental impact and making a significant contribution to the SDGs of expressway projects.