Formulation of surface treatment criteria of adjacent buildings to reduce noise level at selected road junctions in Dhaka city

Abstract

Road noise is exceeding the standard limits in Dhaka city and has become detrimental to human wellbeing. This pollution is mostly caused by the growing number of vehicles, particularly the noise of horns they generate. A road junction is one of the busiest and noisiest places attracting many vehicles and commercial activities. As a result, road users, road side workers, hawkers, shoppers and adjacent building users are exposed to prolonged noise exposure at unacceptable levels, which is a threat to their health and productivity. To reduce the noise level at road junctions in Dhaka city, there may be many options pertaining to traffic systems, noise control regulations, vehicle fitness and road conditions. This research tests the hypothesis, whether surface materials of adjacent buildings play a significant role to reduce external noise level, as an architectural approach to supplement other remedial options. As a part of the methodology, a reconnaissance survey is conducted on thirty road junctions in Dhaka city to select three from those for detailed instrumental field survey. Based on field data, a typical road junction is chosen for parametric study using computer software for acoustic analysis, simulation and prediction for assessing effects of different building surface materials on the reduction of noise levels at road junctions. Results have gone through Analysis of Variances (ANOVA) for assessing significance of the findings and testing of the hypothesis. The findings of this research postulate that, selection of appropriate building surface materials has a significant effect on noise reduction at road junctions; as for an example, a building surface of bricks with holes has better effect on noise reduction compared to that of smooth concrete. As an outcome of this research work, propositions are made in the form of guidelines pertaining to building surface materials for architects, urban designers, engineers and allied bodies in building industry for improving noise conditions at road junctions. Suggestions for future research are also furnished to facilitate further remedial measures for noise problems at road junctions; towards a safe, healthy and liveable city.