Study And Practice On Cantilever Construction Control Of Continuous Beam Bridge Of (36+3×72+36) M Over Qinshui Avenue

Prestressed concrete continuous beam bridge has the advantages of strong spanning capacity and good stability,so it is widely used in the construction of long-span bridges.When using cantilever casting method to construct prestressed concrete continuous beams,it is necessary to monitor the continuous beams in real time because of the long construction period,long-term cantilever status of each temporary T-frame and some uncertain factors which inevitably deviates from the calculated values in the shape and stress of the continuous beams in construction process.This paper expounds the characteristics of prestressed concrete continuous beam bridge,the necessity of construction monitoring and the content of monitoring;The temporary structures such as hanging basket and temporary consolidation of section zero are analyzed and checked to ensure the stability and safety of continuous beam in the construction process;The finite element software MIDAS/Civil 2015 is used to establish the simulation calculation model of the main beam structure of the continuous beam bridge of(36+3×72+36)m over Qinshui Avenue,and the main beam is simulated according to the construction sequence of the construction drawings.Detailed analyze the stress and line shape of the main beam in each construction stage,and obtain the theoretical precast high value of the main beam;Formulated a continuous beam bridge construction monitoring scheme,in the aspect of alignment,the layout and measurement method of elevation measuring points are formulated,in the aspect of stress,the buried position and measurement time of stress sensor are formulated.Each measured elevation or stress must be compared with the calculated value corresponding to the simulation.If the deviation occurs,the reason should be found out and adjusted in the next section of construction to achieve the purpose of real-time monitoring;Finally,the influence of different closure schemes on the stress and shape of the main beam of five-span continuous beam bridge is studied.The proposed closure schemes is proposed by comparing the linear shape and stress of the main beam of different closure schemes after the bridge is formed.