Sound Insulation Performance Test And Analysis Of Timber Framed Structure Floor

The sound insulation optimization design of the timber framed structure floor is the key to ensure the living comfort of the upper and lower space of the building.It is an important consideration to measure the psychological and physical health of the residents and ensure the quality of life.In view of some sound insulation problems of floor currently,this paper studies the acoustic environment quality of the floor according to the framed structure characteristics and the new characteristics of the current living acoustic environment.explores a method to effectively solve the problem of sound insulation of the building floor.It is expected to explore a method to effectively solve the problem of sound insulation of building floors.In this work,a two-story timber framed structure building in Nanjing is taken as the research object.The research contents include the material optimization and structural design of floor,material parameter research,theory calculation and field measurement of structural sound insulation.Systematic research and analysis of airborne and impact sound insulation performance of timber framed structure floor and three kinds of timber framed structure floating floors using cork board,BGL thermal and sound insulation board,EPP sound insulation board,respectively.The influence of the elastic cushion on the sound insulation of the floor is analyzed carefully.The sound insulation and sound pressure distribution characteristics of the four floors under different noise sources are analyzed,and the frequency characteristics of the noise source are summarized through the sound spectrum analysis of standard excitation test and the daily behavioral excitation test.The main research conclusions of this paper are as follows:(1)The airborne sound insulation of cork board in the middle-high frequency range is great,and the airborne sound insulation of BGL thermal and sound insulation board and EPP sound insulation board in the middle-low frequency range is great.Actually,the frequency range for airborne sound insulation of the three elastic cushion materials is summarized.Considering the sound insulation and damping properties of the material,it is preferred that the cork board with a thickness of 20 mm is applied to the elastic cushion of the floating floor structure.Under the same thickness conditions,the material damping ratio is ordered as: cork board>EPP sound insulation board>BGL thermal and sound insulation board,while elastic modulus is ordered as: cork board>EPP sound insulation board>BGL thermal and sound insulation board,ie BGL has greatest elasticity.The correlation between the sound insulation characteristics of the material and that of the floor structure isfurther analyzed,and the correlation between the material damping ratio,the elasticity and the sound insulation of the floor structure is analyzed.(2)The airborne sound insulation of the three floating floors has increased by1-2dB,and the sound pressure multiplier has been improved by 8-18 times.The airborne sound insulation of the floor is improved properly while applying the elastic cushion in floor structure,and the effect is not significant.The airborne sound insulation of the four kinds of floor structures conforms to the sound insulation performance for grade 5 in GB/T 50121-2005 “Rating standard of sound insulation evaluation in buildings”,and meets the sound insulation of grade 3specified in GB 50118-2010 “Code for design of sound insulation of civil buildings”.It also meets the requirements for airborne sound insulation of general residential buildings in GB 50096-2011 "Residential design specification".(3)The measured airborne sound insulation and impact sound insulation of the floor under the condition of closing the door and windows is 15-20 dB and 1-5dB higher than that under the condition of opening the door and windows,respectively.It is proved that the sound insulation of the floor is the key to insulate the sound of the upper and lower space of the building,especially for the middle and lower buildings.At the same time,the influence of doors and windows on the acoustic environment inside the building is also great.It also indicated that the impact sound is mainly transmitted and radiated through the vibration of the floor structure for timber framed structure,and emphasized the importance of floor structure design.(4)The theoretical calculation of the airborne sound insulation-frequency relationship curve of the floor is consistent with the measured values.The sound insulation of different floor structures are analyzed to obtain the airborne sound insulation improvement frequency range of the elastic cushion material.The research shows that the theoretical calculation of transfer matrix method can be effectively used in the optimization design of airborne sound insulation for timber framed floor through theoretical and experimental analysis.(5)The impact sound insulation of the timber framed structure floor can not meet the grading requirements for the sound insulation performance of floor in GB/T50121-2005 “Rating standard of sound insulation evaluation in buildings”.It also can not meet the sound insulation requirements in GB 50118-2010 “Code for design of sound insulation of civil buildings” and GB 50096-2011 “Residential design specification”.However,the impact sound insulation performance of the three floating floors are all Grade 1,and they all meet the impact sound insulation requirements in GB 50118-2010 and GB 50096-2011.(6)The impact sound insulation of floors are measured as follows: floating floor using BGL thermal and sound insulation board > floating floor using EPP sound insulation board > floating floor using cork board > timber framed structure floor.The application of the elastic cushion layer can effectively improve the impactsound insulation of floating floor in the middle-high frequency range,and inprove the impact sound insulation within the middle-low frequency range of the floor particularly.The impact sound insulation of three floating floors was improved by9-10 dB,and the sound pressure multiple has been improved by 10-20 times.The impact sound insulation effect of the floating floor is improved significantly.(7)Impact excitation are divided into standard and daily behavioral excitation,the latter includes music noise excitation,pedestrian excitation including walking and running,jumping excitation,and ball excitation.The distribution of sound pressure energy and the variation of sound pressure with frequency of noise source in different floor structures are analyzed,and the frequency characteristics of the noise source are summarized based on spectrum analysis.(8)Considering the mechanical characteristics,durability and environmental protection of the timber framed structure floor,it is recommended to apply the cork board as an elastic cushion to the floor structure during the construction process.The acoustic environment quality in the interior of the building can be further improved to meet the requirements of higher living comfort by applying the floating floor structure form.In summary,the airborne sound insulation performance of the timber framed structure floor meets the relevant building standards,while its impact sound insulation performance can not meet the relevant standards through sound insulation test and analysis of timber framed structure floor.The floating floor applying elastic cushion structure can meet the requirements of the standard for sound insulation of residential building's floor.And the frequency characteristics corresponding to different noise sources are different.The above provides reference for the research and optimization design and evaluation of sound insulation of timber framed structure in China,which has great engineering application value and practical significance.