Abstract:The structure design conception and calculation analysis of irregular sections in an urban underground complex project under construction are introduced. This project is a huge urban underground complex. Its total construction area is about 1.8 million square meters, which is a shallow buried box-type reinforced concrete structural system. The critical design of this project is to treat the large-span irregular section for the combination and separation locations of road flow. Therewith, the calculation and analysis of the multi-ribbed box section structure are proposed to prove the rationality, reliability and safety of using this design method, which can be referred for the design of the similar projects.