Abstract: Firstly, aiming at the specific requirements of forward design for the steel-concrete composite beam, a multiscale BIM modeling method was introduced, and a model grading scheme based on level of development (LOD) was proposed. Firstly, through the structure tree framework and naming rules, the linkage mechanism of hierarchical models was established to achieve effective transfer of model data at different levels of granularity. Secondly, the basic process of multiscale BIM forward design for steel-concrete composite beam was proposed on the basis of BIM platform, which realized the semi-automatic design of elevation, section and plane of the steel-concrete composite beam by the embedded design logic and construction principles. And the decision table was used to solve the problems of understanding deviation and condition omission under the combination of multiple logic conditions. Finally, the corresponding BIM models according to different LOD were generated, and the model instantiation efficiency was tested. The results show that the application of multi-scale BIM forward design method in the design of steel-concrete composite beams can effectively improve the efficiency of forward design and the reusability of three-dimensional models.

Key words: bridge engineering; steel-concrete composite beam; multi-scale; level of development; building information modeling (BIM); forward design

摘要： 首先，针对钢混组合梁正向设计的具体需求，引入多尺度BIM建模方法，提出了基于模型精细度（level of development, LOD）的钢混组合梁模型分级方案，并通过结构树框架和命名规则建立分级模型的衔接机制，实现不同精细度下模型数据的有效传递；其次，基于BIM平台提出了钢混组合梁多尺度BIM正向设计的基本流程，通过内嵌设计逻辑和构造原则的方式实现钢混组合梁立面、断面和平面半自动设计，并利用决策表解决了多逻辑条件组合下的理解偏差和工况遗漏问题；最后，按照不同模型精细度等级生成对应的BIM模型，并测试模型实例化效率。结果表明：多尺度BIM正向设计方法应用于钢混组合梁设计中，能够有效提高正向设计的工作效率和三维模型的复用性。

关键词: 桥梁工程；钢混组合梁；多尺度；模型精细度；建筑信息模型；正向设计