Application Research On Collision Check Of Bridge Information Models(BIM) Under Construction

BIM technology came into being as the sun is just rising with the rapid development of information technology in the field of engineering construction,which provides an opportunity to solve the existing problems such as collaborative work,resource sharing,virtual reality and information integration and transmission in the traditional engineering construction.The collision detection application of BIM technology has a certain significance in solving a series of problems such as "error,leakage,collision and lack" in the large-scale complex bridge project at the present stage.In this paper,firstly,the collision conflicts problem in the design and construction statges of the project construction are analyzed in depth,and the application framework of collision detection based on BIM is proposed.Secondly,in view of the shortcomings of collision detection function of Revit software and Navisworks software in BIM software system,the relevant secondary development work is carried out with its good expansibility and powerful API.Finally,the parametric three-dimensional digital model of the bridge is built on the two-tier highway and railway cable-stayed bridge with steel truss girder as the engineering background.For the model,static and dynamic(animation simulation)collision detection of the bridge is studied.At the same time,the Midas Civil model is applied to analyze the influence of the setting of pre-camber on the accuracy of bolt holes in a segment of steel truss girder.It provides reference for solving the collision conflicts in traditional engineering construction projects.The main contents are as follows:1.Developing plugin with Revit API for collision detection requirements between individual objects,the collision detection problems is transformed into space intersection of objects element filtering problem to implement a collision detection of a single object.At the same time,the function of extracting relevant information of collision objects is completed.As an auxiliary plug-in for the application analysis of Navisworks collision detection,it makes up for the deficiency of the collision detection function for individual objects.2.Developing plug-ins with Navisworks API for various disorder problems in the collision points of the model,the collision points of large and complex structures are quickly classified and combed,and the collision points are clearly marked in the view interface,which makes the collision detection results clearer.3.By means of Revit software,the main structure of bridge,auxiliary structures,temporary structures,construction equipment and other family libraries are established,and three-dimensional digital model of the two-tier highway and railway cable-stayed bridge with steel truss girder is created.On this basis,according to the characteristics of engineering background,Navisworks software was used to perform respectively the internal structure of the main tower static collision detection and dynamic collision detection such as the main tower construction,preassembly of main beam segment,floating crane hoisting,main span navigation and so on,to solve all kinds of conflicts problems existing in the structure design and construction process in engineering.4.By means of Midas Civil,the analytical model of cable-stayed bridge with steel truss girder is established.By calculating the theoretical pre-camber as the target reference value,the expansion and contraction amount of the connecting chords is obtained,and then it is converted into the influencing factors of bolt hole location.In view of the phenomenon of staggered holes in bolts,the digital three-dimensional model is set up by means of BIM technology,and the position of the bolt hole is accurately positioned and the virtual assembly is carried out.It is check the problems of space conflict among the bolt,the splice plate and the bolt hole on the chord to meet the requirements of controlling the assembly precision of the construction.