The Research On The Structure Design Of No-rivet Noise Barrier Unit Plate

In recent years,the infrastructure construction is in the process of being developed fast throughout the whole country in China.According to the strategies and the policies from the Central Government,the urban rail transit,urban elevated,highways and high-speed railways among the whole China will achieve a considerable scale until 2020.The different kinds of modern traffic system make it convenient and easy for people to go out,but the environment pollution caused by the traffic system is worthy of attention,especially the traffic noise pollution.It is a very effective solution to set the noise barriers to reduce the traffic noise pollution,the development of traffic industry drives the great development and expansion of the noise barrier industry.The metal noise barriers with rivet structure and concrete noise barriers are widely applied in the current projects.The phenomena such as rivet off,hole corrosion,and rivet loose etc on the metal noise barriers with rivet structure will extremely endanger the normal traffic.The fabrication and installation process of concrete noise barriers are so complex because of its high density,and the noise reduction performance is so general.The concrete noise barriers will affect the overall landscape of the surrounding environment meanwhile.In conclusion,it is necessary to develop a new kind of noise barrier with no rivet structure.The mechanical properties and acoustic properties of the noise barrier plate are required extremely high in the high-speed railway projects.So the development of the new kind of noise barrier with no rivet structure is strictly accord to the noise barrier plate standards in the high-speed railway projects.According to the above situations,the main research contents of the paper are as following:1.The load values acting on the noise barriers were analyzed and calculated.By comparing the measured results and referring to the wind pressure calculation method in domestic and abroad,the high-speed railway wind pressure load values were calculated.The bending resistance load values were determined by load combination.2.Based on the force theoretical calculation of the noise barrier plates and studies on the original metal noise barrier structures,a new kind of no-rivet noise barrier plate were designed,this kind of noise barrier unit plate were connected by the concave convex groove on the back plate and face plate.The external metal structure act as the protective screen body and filled with noise-absorbing material inside.Aimed at the special noise frequency on the high-speed railway,the metal noise-absorbing wedges were set on the face plate with noise-absorbing holes on the face plate at the same time,which makes it sure that the sufficient contact between theincident-noise and the internal noise-absorbing materials.So that this kind of noise barriers make good performance on reducing low frequency noise and middle-high frequency noise.3.With the help from the finite element analysis software ANSYS,the fatigue resistance and the bending resistance of the noise barrier unit plate were simulated,the simulation results were accorded with the theoretical calculation results.The maximum deformation of the noise barrier unit plate was 7.16 mm,which was much smaller than the unit plate deformation requirements in the noise barrier standards.The maximum stress of the noise barrier unit plate was 139.2MPa,which was also smaller than the yield strength of its material.The unit plate structure is security.4.Through the mechanical property and acoustic property experiments conducted according to the national standards on the noise barrier unit plates,the results show that the noise reduction coefficient was 0.75,and the noise transmission loss was 40 d B,both of which were superior than the national standard requirements.The bending resistance experiments were conducted on three groups of noise barrier unit plates.The results show the bending resistance load were all greater than 7k Pa,the mid-span deformation were smaller than the standard limits meanwhile.The unit panels were found remained intact and without any damage after checking the inner and outer surfaces when the fatigue experiment was finished,the noise barrier satisfy the fatigue experiment requirements.