Heavy-weight Floor Impact Sound in Reinforced Concrete Structures

The purpose of this study was to evaluate the floor impact sound isolation systems in reinforced concrete constructions. The floor impact sounds were generated by the standard heavy-weight impact sources, a tyre drop tester and an impact ball. The noise and vibration from the impact sources were analyzed and the relationship between the sound levels and the subjective responses was investigated. From the different residential building structures, it was found that heavy-weight floor impact in a box frame-type concrete structure readily transmits sound to the space below through the bearing walls, whereas the non-bearing walls of a rahmen structure do not readily transmit sound. It was also observed that a linear relation exists between floor impact sound and vibration. In addition, when the noises were evaluated in in-situ conditions, the allowable sound levels were found to be 46dB for the tyre drop tester and 54dB for the impact ball. 1 Tyre drop tester (Bang machine): Weight – 7.3±0.2kg; air-pressure level – (2.4±0.2)×10 2 Impact ball: Weight – 2.5±0.1kg; drop height – 100cm (JIS A 1418-2) 3 Box frame-type concrete structure: Structural system which is structurally supported by 4 Rahmen structure: Structural system which is structurally supported by the reinforced c Introduction More than 50% of the housing in Korea consists of multi-storey reinforced concrete residential buildings having a radiant floor heating system called Ondol. And low frequency impact noise caused by foot traffic is a major complaint in indoor living. However, in Korea, there were no regulations concerning sound isolation for buildings. The lack of restrictions on residents' living patterns has worsened the situation and frequent disputes occur among residents and between occupants and building contractors. In order to improve floor impact noise isolation performance and to increase the sound comfort of apartment building occupants, regulations based on an objective and easily understood measurement and evaluation method using standard impact sources which simulate well human actual impact are required. In Korean and Japanese standards, both light-weight (tapping machine) and heavy-weight (bang machine or 'tyre drop tester') impact sources were utilized. Through the recent improvement of measuring and evaluating methods for floor impact noise, an impact ball was suggested as the second heavy impact source. Tachibana et al. [1] found that an impact ball has similar frequency characteristics to actual human impact noise for several floor structures. As a rating method of heavy-weight impact sound using bang machine, Li,Fmax,AW was regulated in KS. However, this method has different reference curve and single number calculation methods with ISO. Very recently in Japan, the grades for floor impact noise were divided into five grades in the law for housing quality control [2]. In ISO, L'nw, L'nw+CI were regulated, L'n,AW is used to evaluate, measure, assess light-weight impa have calcu usef low Cana uses frequ G weig refer and Fede was perc refer octa discu that stud I gene box inve in ra the were on sour