利用原桥提高桥上桥承载力问题

为了利用原桥提高桥上桥承载力，提出了间隙上下限和分载可行区的概念。建立了将单分载点、双分载点和三分载点3种设置方式统一计算的模型，并利用该模型对装配式公路钢桥架设的桥上桥利用原桥提高承载力的影响因素进行了深入分析。结果表明，单分载点模型是最佳分载点设置方式，同时分载点应尽量设置在靠近跨中位置，从而提供更大的反向弯矩。

Enhancing the carrying capacity of bridge on bridge using pristine bridge

For enhancing the carrying capacity of bridge on bridge using pristine bridge, the concept of feasible sharing-load region and upper and lower limits of interval were defined. A mechanical model consolidating three kinds of modes s etting sharing-load support, such as one sharing-load support, two sharing-lo ad supports and three sharing-load supports to deeply analyze the influencing fact ors of using pristine bridge to enhance the carrying capacity of the prefabricated steel bridge on bridge. The numerical results show that the best mode of setting sharing-load support is setting one obtained sharing-load support. And the su pp ort should be set at the midpoint of bridge span so that the maximum reverse ben ding moment can be obtained.