| The integral hoisting construction method has many advantages,such as shortening construction period,less influence on navigation,less human consumption,high quality of construction and so on.To study the construction safety and closure error when the arch is lifted,according to the integral hoisting construction scheme(lifting tonnage is 6000 tons)of a steel box arch bridge with 450 meters span,the analysis model of the bridge is established by finite element software ANSYS.And an 1:10 scale model is designed and made based on similarity theory,the model test of the bridge was carried out during the tensioning and hoisting process.Finally,the effects of five parameters,such as structure weight,tension of prestressed cables,wind load,temperature and uneven lifting,on the stress and deformation of the arch rib structure are analyzed,and the sensitivity of the parameters in the lifting process is discussed.The results of the study are shown as follows:(1)During integral hoisting construction of steel box arch bridge,the stress of lifting point section of the arch rib is large,and the local stress on the local structure is also large,which should be paid attention to in construction plan.(2)During integral hoisting construction,compared with the scheme without prestressed cables,the horizontal prestressed cables can reduce the horizontal displacement of the structure by 92.7%,reduce the vertical displacement of the structure by 98.7%,and reduce the stress of the arch rib by 59.4%.(3)There are three main parameters affecting the displacement of the arch rib,according to their sensitivity,the decreasing order is tension of prestressed cables,dead-weight and temperature.When the construction scheme is designed,according to dead-weight and temperature condition,the suitable pretension should be selected to make the horizontal relative deformation of the arch rib close to zero,which can meet the requirement of the closure error.(4)The construction of uneven hoisting will greatly increase the stress level of the cross bracing in arch rib structure. |
