Static And Fatigue Analysis Of Fully Enclosed Noise Barrier On The Freight Railway

In recent years,noise pollution is becoming increasingly serious because of the acceleration of urban traffic construction.For urban roadways and railways,noise barrier is the main way to decrease the noise and improve the environment.A lot of research has been made about the acoustics and mechanics performance of plain upright noise barriers.With the fully extension of the modern transportation network,some freight rail lines will be built cross the region with high environmental assessment requirement inevitably.Because traditional noise barrier can't entirely meet the noise reduction requirement,fully enclosed noise barrier structure with large height emerges at the right moment.At present,fully enclosed noise barrier will be used in “The Birds of Paradise” zone of Shenmao railway.Under this background,this paper aims at making a study of the static and fatigue properties about the fully enclosed concrete plate noise barrier from the following aspects,and making suggestions about the structure design:(1)Static loading test of the 4-span test section of the noise barrier was made to demonstrate the accuracy of the numerical modal established by ANSYS through comparison of the stress measuring results got by the spot test with numerical calculation.(2)The numerical modal of a whole section of sound barrier was established by the same way and the distribution of internal force in 6 kinds of common working conditions was analyzed.Then,column base of the noise barrier was taken out to be the study object and its elaborate numerical modal was established by ANSYS.Parameter adjustment of the contact element was made to make the stress distribution in the numerical modal more practical when there was no external load.Static loading test of the column base was done to verify the veracity of the numerical modal.(3)Time history analysis of the internal force in the column base was made under train fluctuation wind pressure,based on the max internal force under max positivefluctuation wind pressure,the equivalent fatigue load was got by numerical calculation of the column base modal.Finally,fatigue test of the column base was made under equivalent fatigue load.After 2 million times of cyclic loads the amplitude of cyclic fatigue load was gradually increased until cracks produce or bolts loose,the damage form of the structure was researched.Through the above study,it can be concluded that the strength of the concrete plate fully enclosed noise barrier under all common working conditions meets requirements.In the service life,no fatigue damage will occur in the noise barrier.Under larger fatigue load,slightly bolt looseness will happen.Therefore,tightening torque could be controlled to avoid bolt looseness during design phase,and the bolts should be checked regularly.