Research On Design Wind Load And Wind Vibration Response Of Catenary On Canyon Bridge

Catenary is the power supply structure of electrified railway,whose deformation and vibration response to wind load directly affect the operation and traffic safety of trains.Due to the amplification effect of specia l terrain,the design wind speed on bridges is often higher in canyon,where the design wind load value of catenary has become one of the most crucial issues in the construction of high-speed railway.A high-speed railway in western China whose bridge-tunnel ratio is up to 90% passes through the canyon area many times.This paper takes a canyon-bridge catenary of this railway as the object to study its structural design wind load and wind vibration response characteristics.The main research contents and corresponding conclusions are as follows:(1)The correction coefficient of design wind speed of canyon-bridge catenary is studied,and the wind load correction formula for canyon-bridge catenary design is proposed.The CFD numerical simulation of a canyon terr ain along a western railway in China is carried out.The terrain correction coefficie nt value calculated is more than 1.7 times of the standard value.Through the wind tunnel test of bridge-deck rigid segment model,the wind speed correction coefficient of the catenary is 1.12 times of the standard value when the bridge deck is installed with 3m high and 30% air permeability barrier.(2)Through a series of 1:1 scale sectional model wind tunnel tests,the change of the catenary’s shape coefficient with wind speed,wind direction angle and turbulence intensity under different cable and line layouts was studied.The shape coefficient difference of the double-cable single-line and single-cable single-line catenary was compared with the standard value.The results indicate that the test values of the shape coefficient of the double-cable,single-cable and contact line are 0.8,1.47 and 1.35 times of the standard value,respectively.(3)The dynamic characteristics and wind-induced vibration response characteristics of the 2-span,9-span and 31-span catenary models were compared and analyzed by finite element calculation,and the 2-span double-cable single-line catenary aeroelastic model was designed and manufactured for wind tunnel test.The deviation between the finite element calculation results of the wind-induced vibration response of the catenary and the wind tunnel test results was within 10%,and the wind-induced vibration coefficient value of the catenary was 1.2 based on the wind tunnel test data.(4)Based on the wind load correction coefficient and wind-induced vibration response finite element analysis of the canyon-bridge catenary,the wind load and wind-induced vibration response characteristics of the typical canyon-bridge catenary are studied,and the differences in the wind-induced vibration response characteris tics of the double-cable single-line catenary under the wind load of both the canyon an d the standard are compared.The results show that the mean and standard deviation of the wind-induced displacement of the canyon-bridge catenary can be 1.3 times than that of the standard load,and the influence of the canyon wind and the bridge girder on the wind-induced response of the catenary is significant.