一、前言桁架拱渡槽结构轻巧,造型美观,整体性较强,对软弱地基适应性好,是灌区配套工程中一种较新的结构型式。经各地实践,已建成的桁架拱渡槽有:下承式、中承式、上承式和复拱式四种型式。复拱桁架渡槽是在前三种桁架渡槽型式的基础上提出来的,在相同条件下与前三种相比,具有内力沿跨度分布均匀,拱的性能显著,杆端弯矩小,平面刚度大,承载能力高,钢材用量少等优点。本文专门介绍复拱桁架渡槽的设计和计算。计算时,我们选择了不同标号混凝土及不同的荷载组合进行了三种情况的计算,对每种情况又作了不同流量,不同矢跨比和不同断面尺 I. INTRODUCTION The truss arch aqueduct has light structure, beautiful appearance, strong integrity and good adaptability to weak foundation. It is a relatively new type of structure in the supporting project of irrigation area. Practices have been completed, the truss arch aqueduct has been built: under-bearing, in the bearing, bearing and complex arch four types. The multi-arch truss aqueduct is proposed on the basis of the first three truss aqueduct models. Compared with the first three truss aqueducts, the internal arch truss aqueduct has uniform distribution of internal forces along the span, remarkable performance of the arch, small bending moment on the rod end, Large, high carrying capacity, less steel and other advantages. This article is devoted to the design and calculation of multi-arch truss aqueduct. In the calculation, we have chosen three different types of concrete and different load combinations of the calculation of the three cases, in each case made a different flow rate, different sag ratio and different section ruler