摘要:重庆李家沱长江复线桥主桥采用路轨同层非对称布置的双塔双索面斜拉桥结构形式，其跨径布置为(68.4+150.8+454+161.3+102.2+50)m。该项目为重庆轨道交通18号线的关键控制性桥梁工程，具有涉及专业广、结构构造复杂、施工工序繁多等特点，为了确保项目工程质量，亟需采用正向设计手段。为保证BIM模型高质高效建立以及在不同软件间模型信息的有效传递，采用“R+GH+R”软件体系开展全过程正向设计。本文阐述了设计阶段全过程正向设计分析与施工及运营过程中的数智运维，借助自主研发的桥梁方案智能适配系统、BIM模型管理系统以及数智运维云平台，根据定制化的二次开发实现场地模型快速生成、计算信息模型交互、云计算、施工仿真、720、VR、3D打印等技术，大幅提升方案创作和正向设计效率，拓展BIM技术的产品服务链。利用正向设计手段，提升桥梁设计品质，为同类型桥梁正向设计的BIM技术应用提供参考。

Abstract: The main bridge of Lijiatuo Yangtze River double track bridge in Chongqing adopts the structural form of double tower and double cable plane cable-stayed bridge with asymmetric layout of track on the same floor, and its span is(68.4+150.8+454+161.3+102.2+50)m. The project is the key control bridge project of Chongqing rail transit line 18. It has the characteristics of wide disciplines, complex structure and various construction processes. In order to ensure the project quality, it is urgent to adopt forward design method. In order to ensure the high-quality and efficient establishment of BIM model and the effective transmission of model information between different softwares, the "R+GH+R" software system is adopted to carry out the whole process forward design. This paper describes the forward design analysis in the whole process of the design stage and the digital intelligence operation and maintenance in the process of construction and operation. With the help of the independently developed bridge scheme intelligent adaptation system, BIM model management system and digital intelligence operation and maintenance cloud platform, according to the customized secondary development, the technologies such as rapid generation of site model, interaction of computing information model, cloud computing, construction simulation, 720, VR and 3D printing are realized, the efficiency of scheme creation and positive design is greatly improved, and the product service chain of BIM technology is expanded. The forward design method is used to improve the design quality of bridge, and provide so as to provide reference for the application of BIM technology in the positive design of similar bridges.