ABSTRACT
Along with the development of information technology, the informatization and intelligentization of bridge design, construction, project management is the tendency in bridge industry, to which Building information modeling (BIM), as the core of the information revolution in design industry, has brought great changes. In this paper, the project of Second Wuhu Highway Bridge over the Yangtze River, located in Anhui Province, China, is taken as the background of the research. This bridge is a fully floating cable-stayed bridge with four cable planes and distyle component column pylons. The span arrangement of this bridge is 100 + 308 + 806 + 308 + 100 m. U-shape saddles are used in the background project. The steel strands start from the anchorage, pass through the u-shape saddle and come back to the anchorage on the other side at the same cross section. The saddles are vertically superposed to anchor the four-plane cables, at a certain angle to the axis of the pylon. Each group of saddles is composed of 2 pairs and each pair has 2 single saddles on two sides. 3D models are used to analyze the spatial distribution of the saddles. Results show that all anchor bodies surround the surface of a virtual cylinder. 8 ~ 25# groups are in similar spatial pattern and have less overlap, so an integral installation method is taken. 4 ~7 # saddles have larger angles and longer weaving section between two adjacent groups. So they are hoisted and installed one by one. Saddle integral installation method means that one group of saddles and a stiff skeleton are assembled together on the ground and then installed on the pylon. The integral structure is composed of 4 anchor bodies of this group, 4 conduits of the next group and skeleton of this group. The anchor body and conduit is connected after being hoisted and positioned onto the pylon. A lot of factors should be considered in skeleton design, such as stiffness and economy, of which saddle positioning plays an important part. 3D models are built in BIM software for skeleton design, which helps decrease skeleton overlap or collision. BIM models can also help optimize the installation scheme, such as the connection of skeleton and sequence of complex welding points. They can also be useful to develop positioning method of different skeleton, to show the spatial position of each bar, to determine the size of the locating plates and to develop reliable quick connection method of anchor body and conduit. Another problem of conduit temporary fixation is also solved by visualization function of BIM models. Based on 3D models, a network information platform is built. Key information and data are uploaded from network terminals, and then transmitted into the server, which will be updated through secondary development programs. Both BIM models and information can be shown on a network platform. Participants of the project can be aware of what is going on at the construction site and can give effective instructions in time, thus improving efficiency.
