An inverted syphon is a hydraulic structure utilized to convey open channel flow under obstructions. This study focuses on identifying the safest and optimum design of a sewage inverted syphon to avoid intersection problems with immovable infrastructures. Hydraulic design requirements, inlet and outlet distribution rooms features and protection of expected loads on syphons’ pipes were taken under consideration in formulation the optimization model. Further, different pipes’ material, many levels of the design variables and parameters were incorporated in the model to highlight the effect of each variable on the optimum design. The objective function was the minimum construction cost, and the design requirements were presented as constraints in the model. Results demonstrated that the optimum design for discharges ranging from 0.38 m³/sec to 0.95 m³/sec was Poly Vinyl Chloride (PVC) syphon, but for other discharges the reinforced concrete type was the optimum. Compared to traditional design, the optimum solutions provide a significant cost reduction. Concrete inverted syphon was the optimum possible solution to solve intersection problem of Al-Hashmea sewer project to pass sewage flow under the railway.

倒虹吸管是一种水力结构，用于在障碍物下输送明渠水流。本研究的重点是确定污水倒虹吸管的最安全和最佳设计，以避免与不可移动基础设施的交叉问题。在制定优化模型时，考虑了水力设计要求、入口和出口配电室特征以及虹吸管上预期载荷的保护。此外，不同的管道材料、多层次的设计变量和参数被纳入模型，以突出每个变量对优化设计的影响。目标函数是最小的建设成本，设计要求在模型中作为约束条件提出。结果表明，放电范围为 0.38 m 的最佳设计³ /sec 到 0.95 m ³ /sec 是聚氯乙烯 (PVC) 虹吸管，但对于其他排放，钢筋混凝土类型是最佳的。与传统设计相比，最佳解决方案显着降低了成本。混凝土倒虹吸管是解决Al-Hashmea下水道工程在铁路下通过污水流交叉问题的最佳可能解决方案。