Construction Control And Risk Assessment Of Continuous Rigid Frame Bridge During Cantilever Casting Stage

In recent years, with the development of science and technology, the continuous rigid frame bridges have been developed rapidly. All kinds of uncertainties in construction become obvious due to the increase of the span length. The engineering construction of continuous rigid frame bridges is confronted with high risk, active measures must be taken to cope with it. Based on the construction of BeiJing urban rail transit line YiZhuang-the Continuous Rigid Frame Bridge over JingJinTang Highway, the construction control and risk assessment of prestressed concrete continuous rigid frame bridge during cantilever casting stage.First, the basic theory of control technique and risk assessment is studied in this paper and the basic method of control calculation for continuous rigid frame bridges is studied. Second, simulation model of the Continuous Rigid Frame Bridge over JingJinTang Highway is established using the large universal finite element software Midas/Civil. Each construction stage is calculated and analyzed in detail. At the same time, monitoring of stress, displacement and temperature was carried out during the bridge construction. The erection elevations of formwork for segment concrete were given by comprehensive analysis to ensure that the geometry and the internal force state meet the design requirements. Based on study on bridge accidents, structure calculation and analysis, consulting the owners and experts and on-site investigation, risk identification during the construction of the Continuous Rigid Frame Bridge over JingJinTang Highway is carried out. Risk grades is evaluated during the construction using the Delphi method and risk control measures are proposed.Study results show that there are some differences between actual stress state and theoretical analysis. Maximum cantilever, closure and construction completion states are the most unfavorable three construction stages, so these stages should be the key objects for construction control and risk assessment due to the greater construction risk caused by various uncertainties.