Application Of Locking-Viscous Damper System In Long-Span Suspension Bridge

Long span suspension bridges have become the main form of long span bridges due to their advantages such as strong spanning capacity,low material consumption,light weight.However,suspension bridges have low stiffness and lack of effective longitudinal constraints,which can easily generate significant structural responses under vehicle or seismic loads.Based on a suspension bridge with a main span of 2300 m,this paper proposes a scheme of "Locking device with pressure relief valve + Viscous damper " system to control the structural response of the suspension bridge.This paper firstly introduces the development of long span suspension bridges in China and the research and application status of viscous dampers in the field of bridge seismic resistance.Aiming at the problem of oil leakage caused by high-frequency reciprocating motion of viscous dampers in use,a scheme of "Locking device with pressure relief valve+ Viscous damper" is proposed.Using Midas Civil finite element software to build a threedimensional model and conduct dynamic characteristics analysis to obtain information such as frequency,period,vibration mode characteristics,etc.of the bridge.Based on the situation of this bridge,a suitable mechanical calculation model for viscous dampers is introduced and selected.Secondly,this paper analyzes and compares the seismic response results of suspension bridge under uniform excitation and different apparent wave velocity traveling wave effects under the "longitudinal + vertical" combined seismic action of different strengths,and explores the seismic resistance of the "locking viscous" damper system under uniform excitation and traveling wave effects.The research shows that the "locking viscous" damper system can better control the seismic response of the bridge structure under uniform excitation,the seismic response of suspension bridge is more complex when considering the traveling wave effect,and the "locking viscous" damper system only has a certain vibration reduction capacity within the specific apparent wave velocity range.Finally,under consistent excitation,this article takes the dynamic response of key parts of the structure under rare earthquakes and moving vehicle loads as the control objectives,and conducts parameter sensitivity analysis of viscous dampers and locking devices to determine the optimal parameter values.The paper verifies that the locking device can effectively control the structural dynamic response under frequent earthquakes and vehicle loads.When working together with viscous dampers,it can play a better vibration reduction role than a single vibration reduction system,with a maximum vibration reduction rate of up to 90%.The paper also analyzed the interaction of viscous dampers between tower beams and cable saddles under rare earthquakes,and further compared the advantages of locking devices with pressure relief valves compared to ordinary locking devices.This paper proposes a new " Locking device with pressure relief valve + Viscous damper " system solution for the dynamic response of suspension bridges under earthquake and vehicle loads,which can provide a reference for the vibration reduction design of long-span bridges.