Research On State Evaluation And Stengthening Transformation Of Railway Bridge Structure

As the service life of the bridge structure increases,the concrete will be cracked by the influence of external factors,thus affecting the operational safety of the bridge.In order to ensure the improvement of the carrying capacity of the railway system,it is necessary to evaluate the state of the bridge structure.For the evaluation of bridges that do not meet the requirements,appropriate strengthening measures are needed.In this paper,the research is carried out on the middle bridge of Baoheng Road of Shuohuang Railway.The main research contents are as follows:(1)The short-term strengthening of the bridge structure was carried out by adhering the carbon fiber cloth on the surface of the bridge structure.The influence of the carbon fiber cloth reinforcement measures on the mid-span amplitude and the pier top amplitude of the bridge was analyzed.The results show that the amplitude of the bridge span and the amplitude of the pier top are significantly reduced after the carbon fiber cloth is adhered to the surface of the damaged bridge structure.Taking the mid-span lateral amplitude of the first-hole bridge as an example,the maximum amplitude before reinforcement is 0.59 mm,and the maximum amplitude after reinforcement is 0.15 mm.It shows that the carbon fiber cloth reinforcement measures have achieved good results.(2)In order to ensure the long-term safety of the bridge structure,the bridges with carbon fiber cloth were replaced with steel-mixed composite beams,and the effects of short-term strengthening measures and long-term strengthening measures on the bridges were analyzed.The results show that the vibration amplitude of the newly installed steel-mixed composite beam is significantly smaller than that of the carbon fiber-bonded bridge under the same train load.Taking the lateral amplitude of the first hole bridge as an example,the maximum displacement of the steel-mixed composite beam is 0.11,and the maximum amplitude when bonding the carbon fiber cloth is 0.15 mm..(3)Through the test of the lateral amplitude of the bridge pier before and after the reinforcement,the variation law of the displacement of the pier top with the formation speed under different train loads is obtained.The results show that the effect of the reinforcement on the main beam of the bridge is not obvious to the lateral amplitude of the pier.