Strength Analysis And Health Monitoring Of A Continuous Rigid Bridges In Chongqing

With the continuous development of China’s economy and the accelerated urbanisation process,the transport load is bound to increase.In addition,under the comprehensive influence of external environmental factors such as climate change and natural disasters,the service life of bridges may not be able to meet the design requirements,which may cause serious bridge collapse and endanger the lives and property of the public.The current means of monitoring the health of bridges in China not only consumes terms of personnel,physical and budgetary resources but is also largely dependent on experiential experience,making it difficult to make accurate and reliable safety assessments.Therefore,it is particularly important to monitor the health of bridges and provide early warning.The main features of this thesis are as follows:(1)The finite element method was used to analyse the loads on this example bridge.A three dimensional model of the bridge was built and numerically simulated using ANSYS software,while its stresses under the first class highway loads were simultaneously investigated to check the correctness of the model.(2)The effect of three freight vehicle models on the mechanical properties of the bridge at different locations under overload conditions is investigated.Based on the results of the bridge force analysis,the detrimental locations of the bridge and the maximum limit weight criteria of the bridge for the three vehicle models are derived: 33 tonnes for the two-axle model,66 tonnes for the four-axle model and 94 tonnes for the six-axle model.(3)The dynamic response of a bridge under moving loads is analysed.An amplitude analysis of the bridge was carried out to derive the self-oscillation frequencies and vibration characteristics of the bridge structure.The results of the transient dynamic response analysis are used to derive the effect of vehicle speed on the vibration velocity and vibration acceleration in the span of the bridge,so that the working state of the bridge structure can be deduced to support the consequential health monitoring.(4)The development of a BIM based bridge health monitoring system.Designed a molybdenum sulphide resonant pressure sensor,and used BIM software to parametrically and modularly build a three-dimensional model of the bridge;set hazard threshold monitoring levels based on sensor signal data;developed a bridge visualisation monitoring plug-in,designed monitoring operation interface buttons,and encapsulated monitoring functions into the Revit interface,finally realising bridge health monitoring based on the BIM platform.