Virtual Pre-assembly Technology Of CFST Arch Bridge’s Arch Rib Based On BIM And Point Cloud

Pre-assembly,as an essential and important process of assembly building,can discover the unqualified components caused by manufacturing and other factors in time,so that the construction personnel can take corresponding measures in time.Due to the limitation of site and equipment,the entity pre assembly can not meet the needs of more and more large-scale prefabricated buildings.At present,there are few cases of virtual pre assembly for this kind of building,and a set of mature virtual pre assembly is urgently needed to solve the simulation and prediction of large-scale assembly structure.As a typical assembled structure,the prediction of the arch rib shape of CFST arch bridge is particularly important for this kind of long-span structure.However,it is very difficult to predict the completion status of the whole structure effectively by using the entity pre assembly,so it is necessary to study a set of reliable virtual pre assembly technology to predict the arch rib shape of CFST arch bridge.The main contents of this paper are as follows:(1)Firstly,the influencing factors of 3D scanner accuracy are analyzed to determine the data collection rules of arch rib point cloud.Then,for the key features of arch rib,such as flange plane,bolt and main chord,a set of technical route of feature parameter extraction is summarized.(2)Two coordinate alignment algorithms,EOPA and GPA,are studied.According to the characteristics of the two algorithms,they are applicable to coordinate alignment of different objects of arch rib.Among them,EOPA is used to complete the alignment of parameter reverse arch rib and design arch rib,and the linear detection of main chord is carried out;GPA is used to complete the alignment of bolt holes of reverse arch rib,and the deviation of bolt holes at the end of arch rib is obtained.(3)For the complex multi limb arch bridge,taking 155 m CFST arch bridge as an example,CATIA is used to reverse the BIM model of arch rib.In addition,in order to accurately analyze the full bridge alignment completed by the real arch rib splicing,ABAQUS finite element analysis software is used to carry out three-dimensional solid finite element analysis of the arch rib,forming a complete BIM and point cloud virtual pre assembly technology of the arch rib of CFST arch bridge.In order to verify the reliability of the technology,the predicted arch rib alignment is compared with the whole bridge alignment.(4)In the practical engineering,because of the factors of manufacture and installation,it is difficult to avoid the end deviation of arch rib.In order to explore the influence of the end deviation of arch rib on the alignment of arch rib,several representative end deviation of arch rib are set up.