Experimental Study On The Temperature Field And The Thermal Deformation Of The Continuous Beam And Frame Piers Bridge On The Jinqin High-speed Railway

The continuous beam and frame piers system is widely used as one of the methods to cross existing highspeed railways in our country. Frame piers system has a flexible arrangement and strong spanning capacity, but its force analysis is more complex than column piers system;besides, the track irregularity caused by temperature field of the crossbeam of frame piers system has direct influence on the safety and amenity of running.Taking the bridge on the Jinqin high-speed railway(a7×16m continuous beam and frame piers system in Jingshan Railway) as research object,the finite element calculations are completed by using MIDAS finite element software.And the temperature field and thermal deformation are observed according to the results. The details of the paper are as follows:1. This paper introduces several kinds of temperature field as well as some of the concrete girders temperature gradient models according to different national norms. Experimental and theoretical researches of thermal deformation of concrete box bridge under temperature load are reviewed.2. According to the regulations of the railway standards of China, the theoretical thermal deformation of the7×16m continuous beam and frame piers system under temperature load is calculated by using finite element software.3. The temperature field and thermal deformation of the bridge were observed both when the7×16m continuous beam and frame piers system was just completed and when the system was in high temperature. Difference is found between the temperature field observed in the two kinds of environment and the temperature field based on the railway standards. The conclusion is that using the thermal deformation caculated based on the values from the railway standards is safe.4. The theoretical thermal deformation calculated based on observed temperature load by the finite software fits the theoretical thermal deformation well, which shows that the finite model is correct and analysis of temperature effects on the model based on the railway standards is safe and has enough margin of safety.