Bridge-borne noise pollution caused by train-induced bridge vibration has attracted more and more attentions due to its low-frequency characteristic.In order to investigate the numerical simulation technique of bridge...Bridge-borne noise pollution caused by train-induced bridge vibration has attracted more and more attentions due to its low-frequency characteristic.In order to investigate the numerical simulation technique of bridge-borne noise and noise reduction methods,a simply supported prestressed concrete (PC) box-girder bridge is adopted for study.Based on train-track-bridge interaction theory,the dynamic response of the bridge under a moving high-speed train is calculated in time-domain and assumed as the sound source of bridge-borne noise.Then bridge-borne noise is estimated according to boundary element method (BEM) in frequency-domain.The time-frequency transform is conducted by fast Fourier transformation (FFT).The validity of the numerical simulation technique is verified through comparison with field measurement results.Furthermore,noise reduction methods are proposed and corresponding effects are discussed.Results show that the proposed numerical simulation method is feasible and accurate in assessing bridge-borne noise.The dominant frequencies of bridge vibration and bridgeborne noise range from 40 Hz to125 Hz and from 31.5 Hz to 100 Hz,respectively.The peak frequency of bridge-borne noise near the bottom plate is 63 Hz.Increasing the thickness of deck plate,adjusting the inclination of webs to 0°-12°,strengthening the boundary constraints and adding a longitudinal clapboard are very effective noise control measures.展开更多
To locate and quantify local damage in a simply supported bridge, in this study, we derived a rotational-angle influence line equation of a simply supported beam model with local damage. Using the diagram multiplicati...To locate and quantify local damage in a simply supported bridge, in this study, we derived a rotational-angle influence line equation of a simply supported beam model with local damage. Using the diagram multiplication method, we introduce an analytical formula for a novel damage-identification indicator, namely the diff erence of rotational-angle influence linescurvature(DRAIL-C). If the initial stiff ness of the simply supported beam is known, the analytical formula can be effectively used to determine the extent of damage under certain circumstances. We determined the effectiveness and anti-noise performance of this new damage-identification method using numerical examples of a simply supported beam, a simply supported hollow-slab bridge, and a simply supported truss bridge. The results show that the DRAIL-C is directly proportional to the moving concentrated load and inversely proportional to the distance between the bridge support and the concentrated load and the distance between the damaged truss girder and the angle measuring points. The DRAIL-C indicator is more sensitive to the damage in a steel-truss-bridge bottom chord than it is to the other elements.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50678150,51008250)Program for New Century Excellent Talents in University of China (Grant No. NCET-10-0701)+1 种基金the National High Technology Research and Development Program of China("863" Program) (Grant No. 2011AA11A103)Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20110184110020)
文摘Bridge-borne noise pollution caused by train-induced bridge vibration has attracted more and more attentions due to its low-frequency characteristic.In order to investigate the numerical simulation technique of bridge-borne noise and noise reduction methods,a simply supported prestressed concrete (PC) box-girder bridge is adopted for study.Based on train-track-bridge interaction theory,the dynamic response of the bridge under a moving high-speed train is calculated in time-domain and assumed as the sound source of bridge-borne noise.Then bridge-borne noise is estimated according to boundary element method (BEM) in frequency-domain.The time-frequency transform is conducted by fast Fourier transformation (FFT).The validity of the numerical simulation technique is verified through comparison with field measurement results.Furthermore,noise reduction methods are proposed and corresponding effects are discussed.Results show that the proposed numerical simulation method is feasible and accurate in assessing bridge-borne noise.The dominant frequencies of bridge vibration and bridgeborne noise range from 40 Hz to125 Hz and from 31.5 Hz to 100 Hz,respectively.The peak frequency of bridge-borne noise near the bottom plate is 63 Hz.Increasing the thickness of deck plate,adjusting the inclination of webs to 0°-12°,strengthening the boundary constraints and adding a longitudinal clapboard are very effective noise control measures.
基金supported by the National Natural Science Foundation of China(Nos.51608245 and 51568041)Natural Science Foundation of Gansu Province(Nos.148RJZA026 and 2014GS02269)
文摘To locate and quantify local damage in a simply supported bridge, in this study, we derived a rotational-angle influence line equation of a simply supported beam model with local damage. Using the diagram multiplication method, we introduce an analytical formula for a novel damage-identification indicator, namely the diff erence of rotational-angle influence linescurvature(DRAIL-C). If the initial stiff ness of the simply supported beam is known, the analytical formula can be effectively used to determine the extent of damage under certain circumstances. We determined the effectiveness and anti-noise performance of this new damage-identification method using numerical examples of a simply supported beam, a simply supported hollow-slab bridge, and a simply supported truss bridge. The results show that the DRAIL-C is directly proportional to the moving concentrated load and inversely proportional to the distance between the bridge support and the concentrated load and the distance between the damaged truss girder and the angle measuring points. The DRAIL-C indicator is more sensitive to the damage in a steel-truss-bridge bottom chord than it is to the other elements.
