| As informatization and intelligent technology develops,there is a growing demand for integrating information technologies into bridge construction for smarter construction systems.In complex mountain areas,surrounding geographical conditions are an important factor to consider as they have an overarching impact on bridge construction.This thesis takes a longspan suspension bridge located in a complex mountain area as the subject.By introducing the key technologies of digital twin,the author proposes a virtual bridge construction scene which includes a virtual geographical environment and a twin model of the bridge,performs the numerical simulation of the wind field with the canyon terrain taken into consideration and the simulation analysis of the construction status,and designs and builds a virtual platform for suspension bridge construction in complex mountain areas.The thesis is composed of the following parts:(1)A summary of the basic concept,key elements and features of digital twin,and the explanation of advantages of applying digital twin in bridge construction.An introduction of the key digital twin technologies and relevant software,and the demonstration of the basic components,windows and development modules of Unity,a virtual engine,used in building the virtual bridge construction platform.(2)The set-up of a virtual geographical environment based on multi-source terrain data and a bridge twin model through parametric modelling by BIM technology.The integration of the terrain model and the BIM bridge model,and the optimization of the scene built through organizing and mobilizing terrain data and lightweight and LOD processing of BIM data,to achieve a high-fidelity virtual scene of bridge construction.(3)The CFD modelling for the big-scale bridge site area,the small-scale bridge with the tower,and the small-scale bridge with the girder based on the terrain data.The extraction of the numerical simulation results of wind from different directions through monitoring points and structural monitoring walls placed by Fluent with the wind field in the big-scale model being the boundary conditions of the wind in the small-scale computational domain,to get the distribution rule of wind speed of the plane at the girder height,and the wind parameters and the 3-component aerodynamic force at the girder and the tower.(4)The adoption of Midas Civil for the simulation analysis of the construction process of a long-span suspension bridge with canyon wind’s impact considered: compare the inner forces and line shapes of bridge components between the 2 girder erection plans in each stage of construction;choose the structure with more flattening inner forces and line shapes as the preliminary plan;add the 3-component aerodynamic force obtained from the actual terrain simulation to the plan chosen,in order to consider the impacts of the canyon wind on the bridge in construction;and use the twin data such as the structural internal forces and displacement value in each construction stage as reference to support actual construction.(5)The design and development of a virtual platform for suspension bridge construction in mountainous areas based on the virtual reality engine of Unity,the visualization of simulation data of environmental wind field and bridge construction in the VR scene through research on simulation data integration and modelling,a demonstration of the interface of main modules,specific functions and interaction methods of the platform.All this can offer a straightforward and reliable basis for decision making in bridge construction in complex mountain areas. |
