Spatial Analysis On Load Effect And Research On Key Technologies For Curved Bridges

With the rapid development of expressways and cloverleaf junctions in recent years, higher demands for transport facilities are required, more and more curved bridges spring up like mushrooms in our country. With the extensive use of curved bridges in civil engineering, the research on the theory and practice for curved bridge design and construction are rapidly developed, people are concerned about computing theory and analysis method. However, there have existed cracks in some curved bridges, this phenomenon not only has these reasons of unreasonable design or improper construction, but also has the reason of long-period of overload, and it exerts a negative or even severe impact on the normal operation. Due to these factors resulted from bending-torsion coupling, pre-stressed space effect, etc. in curved bridges, these spatial properties make curved bridges analysis quite complicated, and the calculation of curved bridges can not be simply solved by directly applying straight bridge analysis method. Therefore, accurately analysis these properties obviously of crucial significance to curved bridges for safe construction, operation and further development.On the basis of domestic and overseas research status, by applying 3-D finite element method to the calculation, spatial stress characteristics under different loads of weight, pre-stressed force and live-load are analyzed, then, based on these research achievements, key technologies for curved bridges are discussed in this paper.(1) By considering spatial properties in each stage of construction and operation phase, two types of box-beam curved bridge and T-beam curved bridge are studied by changing curvature parameter. Based on these studies, this paper further proposes the scope of application on each type of curved beam and judgment condition of replacing curve beam by straight beam in design.(2) In order to get to know the spatial effects resulted from pre-stressed force, spatial effects in post-construction stage, impacts of different pre-stressing sequence and stress transverse distribution in curved bridges are analyzed.(3) Based on the loading test of concrete simply supported-to-continuous girder curved bridge, the spatial calculation for the curved bridge is carried out. By loading test studies, pre-stressed reinforcement arrangement in negative moment and pre-stressing lateral landslip of curved bridges by tensioning of steel wires are discussed, this paper proposed reasonable pre-stressed reinforcement arrangement and check formula for pre-stressing lateral landslip of curved bridges, which provide references for civil engineers.