Study On Applicability Of Bridge Weigh-in-motion Technology In Short-to Medium-span Highway Girder Bridges

Small-to medium-span highway bridge is the most widely used bridge type in China.As of the end of 2019,the number of highway bridges in China has exceeded 870 thousand,while the number of small-to medium-span highway bridges accounts for about 87.03% of the total number of bridges in China.However,with the rapid growth of highway traffic volume,the vehicle loads on bridges may be quite different from those designed at the time of design,and the overload situation of vehicles is becoming more and more common.In some extreme cases,vehicle overloading may even lead to collapse of bridges.Therefore,accurate acquisition of vehicle load information on bridges is of great significance for bridge structure design and overload management.Bridge Weigh-in-Motion(BWIM)technology can efficiently identify the weight of traveling vehicles,and has the advantages of convenient installation and maintenance,no need to damage the road surface,and no impact on the normal traffic of vehicles.However,most commercial BWIM systems are mainly applied to small-span girder bridges or orthogonal special-shaped slab bridge,etc.Most of existing studies have also analyzed small-span girder bridges.The comprehensive impact of the technical solutions on the recognition accuracy and stability is still relatively small,and the effects of factors such as vehicle speed,road surface conditions,input noise,and the longitudinal installation position of the sensors on the dynamic weighing of the vehicle are not fully considered.Based on the above situation,this paper studies the accuracy and stability of the BWIM system in light of the most widely used medium and small span highway girder bridges in China.The influence of bridge span,section type,vehicle speed,road level,noise interference and other factors on the vehicle weight recognition accuracy is discussed in depth,and some valuable conclusions are obtained.These conclusions can provide reference for BWIM scheme selection.The main research contents are as follows:(1)the significance of studying BWIM technology is introduced.The development of BWIM system at home and abroad and the research status of BWIM technology are reviewed.(2)the calibraton process of bridge influence line based on dynamic response of bridge and the principle of vehicle area recognition based on strain area method and Moses algorithm are deduced in detail.(3)base on the BWIM method,the weight recognition results of small and medium span concrete simply supported beam bridges are calculated.The effects of bridge span,bridge section type,vehicle speed,road surface roughness and noise interference on vehicle weight recognition are discussed.The results show that the axle weight identification base on small span is the best.The axle load identification effect of simply supported T-beam bridges with longer span is slighty better than that of the small box girder bridges,and the deterioration of pavement condition or higher vehicle speed may have adverse effects on the identification results.(4)the results of vehicle weight identification of concrete continuous girder bridge,concrete simply supported beam bridge and steel beam concrete bridge deck composite beam bridge are compared and analyzed.The results show that the recognition of vehicle weight based on concrete continuous girder bridge can achieve better results under the same span.