Abstract: To achieve breakthroughs in building information modeling (BIM) with respect to designing bridges and tunnels, the Autodesk platform, Infraworks, Civil 3D, Inventor, Revit, and Navisworks software tools are interconnected and further developed. Additionally, a BIMbased forward design method is proposed herein by integrating BIM with the Bentley platform software and geographic information system. (1) The standard library files of the bridges and tunnels are established using Inventor and Revit, and the main structures of bridges and tunnels are parameterized using the Inventor iLogic functionality in the Inventor software. (2) Civil 3D is used for conducting site excavation and extracting route points for route design. The sections of tunnels and bridges having surrounding rocks of different grades are formulated into a measurement table based on engineering hydrogeological data. (3) A C#based design tool is utilized for creating a bridge and tunnel design, which assembles and integrates the lining, steel arch frame, pipe roof, reinforcement net, tunnel gate, shield tunnel segment, immersed tunnel segment, and bridge structures of various grades of surrounding rocks in batches according to the tunnel line in Inventor. This process enables automatic generation of engineering drawings and quantities. Additionally, the Dynamobased secondary development function in Revit is used to develop the forward design of bridges and pipelines based on the bridge and selfadaptation library established using positioning coordinates. (4) Navisworks is employed for visual analysis, construction process management, and surveying and design control. The proposed forward design method has been successfully applied in various projects such as the North Extension Line (including power tunnel) project for the rapid transformation of the Wanjiali road, Dezhou Shangrao expressway project, and ShenzhenZhongshan Link project, realizing forward designs of bridges and tunnels. 

Key words: bridges and tunnels, building information modeling, forward design, secondary development, model deepening application