Design Of The Overall Stability Of Curved Box Girder Bridge

Because the curve bridge can well adapt to the terrain environment, realize the intercommunication of anisotropy of traffic each other over, at the same time lines smooth, crisp, with rhythm, so it has been widely applied in the city three-dimensional traffic and high grade highway, and the box girder bridge is the main. Due to the stress of curved girder bridges and deformation characteristics and the straight girder bridge is larger, but the design and construction of this knowledge is not in place, so that the curve beam bridge across the country appeared some disease, summed up a: plane displacement of girder integral; beam body outside the overturn overturning; piers loss caused by upper beam stability the collapse of these accidents, resulting in adverse effects and economic loss to the society. The problem of overall stability of these phenomena are of curved girder bridge in the design, so how to improve the overall stability of curved girder bridge, avoid to be congenitally deficient bridge structure stability, it is important to.Papers from the stability of geometric design, curve beam bridge design, anti overturning supporting system design are discussed, especially on the design problem of supporting system, the paper use the MIDAS calculation software to carry on the numerical modeling analysis, from the beam body plane constraint support, beam body torsional bearing, pier beam consolidation design three aspects three badges were studied, namely the fourth, five or six chapter of contents.The radial displacement of the curved girder bridge is due to produce a pure planar force(the overall temperature, the shrinkage of concrete, the centrifugal force, the braking force) role; the other part is the radial displacement and torque deformation caused by the beam body. Lateral restraint stiffness of beam body is more big, produce radial displacement of beam body in the plane under the acting force value is small, but at the same time constraint support radial supporting reaction force is larger, so the design should be considered based on specific situation, in terms of general lateral pier beam consolidation stiffness is greater than the transverse fixed support stiffness. The curve beam bridge tangential displacement constraint shoulds not be too strong, otherwise the beam in the whole temperature, the shrinkage of concrete and so on, will produce a planar inverted arch, increasing the radial displacement.Set the torsional bearing location will produce force torque greatly, so as to adjust the torque distribution of girder, pier beam consolidation is torsional double bearing adjusting torque obviously. For single column pier with preset pivot eccentric way adjustable torque distribution, additional reverse torque and eccentricity values into a linear relationship at the same time the eccentric in side pier, will strengthen the torque adjustment degree, is basically only eccentric Pier 2 times the value of torque adjustment. When the curvature is larger, the preset bearing eccentricity can completely eliminate the medial support state of tension, this time should be adjusted torsional bearing spacing, avoid void.Using the pier beam consolidation to adjust the beam body torque distribution, to avoid the bearing cavity. But the curve beam bridge pier beam consolidation to form a structure system of Xiao Gang, pier and girder collaborative stress and deformation. With the pier height reduction, line stiffness increases, in addition to the braking force and the centrifugal force, the pier top the other load effects are also increasing, especially the top of pier longitudinal bending moment of the great effect of My value of axial force effect is negligible in N. When the pier height unchanged, with the increase of the number of fixed pier, the pier top axial force and transverse bending moment changes little, longitudinal bending moment increased to, in addition to dynamic loads and other loads generated My value increased with the increase of the number of consolidation. Therefore in the pier beam consolidation design, should be comprehensive curve bridge substructure stress considered, weighing the pros and cons. When the pier height less than 5-10 m, linear stiffness is bigger, the pier consolidation should be less, and avoid long couplet long side pier of symmetric consolidation.