Analysis And Research On Construction Monitoring Of Cable-stayed Bridge Without Backstays

With the development of social economy and the level of urban construction,bridge design and construction should not only meet the needs of transportation,but also should be coordinated with the landscape of the land to be built,often becoming a local landmark.Among them,the cable-stayed bridge without back cable is a breakthrough in the shape of the traditional cable-stayed bridge,and it is a more beautiful bridge type.The pylons and slender bridge decks without back-stays show a strong and stable sense of power,giving a striking feeling,like a sailboat sailing.However,because there is only one side cable,it is necessary to rely on the self-weight moment of the leaning tower to balance the overturning moment of the stay cable,the force becomes more complicated,and the construction monitoring is difficult.To this end,this paper analyzes and studies the construction monitoring problem of the cable-stayed bridge without back-stays based on Linzhou Yingbin Bridge-Taliang pier-consolidated cable-stayed bridge without back-stays.The main research contents are as follows:(1)Using the finite element method to establish the theoretical calculation model of the Linzhou Yingbin Bridge,the formal assembly inverted iteration method is used to simulate the construction process,and the goal of matching the cable force and the design cable force when the bridge is made is achieved.The construction process is analyzed to verify the rationality and safety of the construction process,and provide a basis for the adjustment of the construction process and construction monitoring.(2)According to the structural characteristics,construction technology and finite element simulation analysis results of Yingbin Bridge,the construction monitoring plan of Yingbin Bridge was formulated,the construction plan and construction sequence of the inclined bridge tower of Yingbin Bridge were determined;During the process,the deformation and stress of the main beam and the pylon and the cable tension of the cable are monitored and analyzed,and the whole process of the construction process is controlled.(3)Considering the mutual influence of the main beam and the pylon shape of the cable-stayed bridge without the back cable,the line shape of the main beam and the pylon of Yingbin Bridge is taken as the control target,the sensitivity analysis of the structural parameters is carried out,which determine that the structural self-weight and the tension of the stayed cable are the main sensitive parameters of bridge construction.The stiffness of large steel pipe supports does not belong to the sensitivity parameters of bridges.(4)Modeling and analyzing the temperature and stress distribution of hydration heat during the concrete pouring process of the pylon,and arranging temperature sensors in the tower to monitor the temperature and distribution.According to the law of temperature variation,the height of the pylon pouring section and the time of demolishing the form-work after pouring are determined.which provide reference for the mass concrete construction in spring in North China.(5)In the actual construction monitoring process,according to the comparative analysis between the measured section line shape and the measured value of the stress and the theoretical value.Taking the linear control as the goal,the least square method is applied to correct the tensile tension of the cable tension in the C1 and C2 tension stages,which reduces the deviation between the theoretical value and the measured value.After the bridge is formed,the line shape and cable force meet the requirements of the specification,and the monitoring effect is good.