小半径曲线梁桥抗倾覆性能研究

Study of Anti-overturning Performance of Small-radius Curved Bridge

依据曲线梁桥弯扭耦合的受力特点,通过力矩平衡原理与几何关系推导出了其抗倾覆稳定性系数计算公式,并提出以该公式为依据进行抗倾覆验算。以某匝道桥梁为例,利用梁格法建立空间有限元模型进行分析计算,根据奇偶跨数、边中跨比、桥梁纵坡、支座间距、单双支座等影响因素对小半径曲线梁桥抗倾覆性能进行了研究。分析结果表明:以该公式为依据进行抗倾覆验算是简便、可靠的,具有一定的工程应用价值。通过设置偶数跨、全桥抗扭支座,增加支座间距可以增加小半径曲线梁桥的抗倾覆性能。对于普通三跨连续曲梁,可以按照弯矩求出其合理跨径比。

Because of the particular mechanical behaviour of curved girder bridge which is called ben- ding-torsion coupling, the calculation formula of anti-overturning stability coefficient which will be used as the basis for anti-overturning checking computation is derived by using the principal of moment equilibrium and geometry relation. In the example of a ramp bridge in Changchun, a finite element model for mechani- cal analysis is established by grillage method. The anti-overturning performance of small-radius curved bridge are studied according to the influencing factors, such as number of span to be odd or even, ratio of side to main span, the bridge longitudinal grade ,. distance between supports, number of supports to be sin- gle or double. The analytical result shows that the formula is convenient, reliable and suitable for engineer- ing application. The following three methods can be used to improve the anti-overturning performance of small-radius curved bridge, which are setting up the number of span to be even, setting up the anti-torsion supports in the whole bridge, and increasing the distance between supports. Reasonable span ratio can be obtained through the correct resulted bending moment of curved girder bridge.