A System Of Safety Evaluation For Concrete-Filled Steel Tube Arch Bridge Based On GIS

Bridge, which had play an important role in country economy and society life, is the node of the road-net and its condition is relative to the smooth of the whole road-net system. In company with the bridge accident in the whole world, everyone pays more attention to the existed bridge especially the long-span bridge. The safety evaluation has become the most popular problem in the bridge engineering field.In this dissertation, a concrete-filled steel tube arch bridge evaluation model based on integrative evaluation model is established. It's formed by three-layer evaluation index system which contained eleven first index, twenty second index and two hundred and fifty-two third index. The principle in model is Analytical Hierarchy Process (AHP), Delphi Method and etc while considers the structure function. GIS is used in bridge evaluation to solve the problem of complicated data. Object-Oriented Design (OOD) is used to program a system of safety evaluation for concrete-filled steel tube arch bridge based on GIS. This system is practiced on Nan Ni-du bridge and has a great effect after analyzes relative result. The system that has theory and practicality has both functions of evaluation and management. It has the advantage of practicality, manageability and expansibility while achieves visualization and promotes the agility and visual. The main achievements are briefly mentioned as follows:1. Describe the existed safety evaluation method of bridge structure in the world and discuss the connotation and develop trend of bridge safety evaluation. Point out the research trend of bridge safety evaluation is integration, systematization and intelligent.2. Combine AHP and real project to set up a three-layer safety evaluation index system of CFST. Decide the corresponding relationship between component damage degree and damage level. The health condition of component is estimated by zero ~ five damage degree and ultimate bridge safety condition is divide into great, good, normal, bad and dangerous which describe as zero ~ one zone. The principle of how to distribute the weight of evaluation index is decided by Delphi Method. The weight of Nan Ni-du bridge index is determinate after researching the CFST and managing the weight by centesimal system.3. Established the GIS feature system based on AHP by dividing feature layers and features while combined the evaluation index system to solve the problem thatmultilayer can't be set in GIS software. The CFST visual model is set up in virtue of the advantage of visual model, feature display, symbol annotate and special drawing.4. Combined the FoxPro database technology and real project to design the GIS bridge database. Set the GIS database as first index—table, second index—record, third index — field. Integrate the advantage of GIS database that easy for management and FoxPro database that easy to set up for storing a mass of bridge database orderly and transferring reconcilably.5. Visual Basic language is used for GIS database secondary development by the technology of ActiveX Data Object (ADO) control. The CFST safety evaluation system based on GIS has been programmed to achieve the systematization, integration and automatization. Nan Ni-du bridge damage degree and weight of index were input in the system and the evaluation result is consistent with the fact. It shows that this system has great visual effect and data management function to ensure the objectively of evaluation result while do scientific evaluation to CFST.