Safety Evaluation For Large-span Steel Truss Tied Arch Bridge Based On Fuzzy Analytic Hierarchy Process

In recent years, our country’s traffic volume increased year by year with the rapid development of transportation industry. As an important part of the highway, the bridge is becoming more and more important. Arch bridge with its beautiful appearance,reasonable structure, great leap ability and other advantages in our country has been well applied. The assessment of health condition of arch bridge is the basis of its safety operation. This paper sets up evaluation model for steel truss tied arch bridge based on fuzzy analytic hierarchy process. Taking a steel truss tied arch bridge in Zhejiang province for an example to show the process of the evaluation of steel truss tied arch bridge. And it provides reference for similar projects, has a good engineering significance. Also due to the number of arch bridge is very seldom in our country and even in the world, the research is relatively weak. Therefore, the study of large-span arch bridge comprehensive evaluation also has a good research value.The main researches are presented as follows:1. Discuss the development of arch bridge. Analyze the advantages and disadvantages of the existing bridge comprehensive evaluation method and the application situation. Analysis the common disease of arch bridge. And determine the detection and monitoring indicators to provide a basis for the establishment of a comprehensive evaluation model.2. Discuss the principle and application of fuzzy analytic hierarchy process.Analyze the analytic hierarchy process scale and select 9/9~9/1 scale to structure judgment matrix. By analyzing the advantages and disadvantages of the fuzzy synthesis operator, a new fuzzy synthesis operator is proposed. Contrast the equalization coefficient of variable weight principle.And propose the value of "a" in different weights and different points. A kind of variable weight principle is proposed.for the fuzzy comprehensive evaluation method of bridge.3. Establish the model of large-spsn steel truss tied arch bridge using MIDAS finite element analysis software.And analysis of the force, so as to determine the specific layout of the measuring points. Damage was simulated by changing the elasticity modulus. And calculate the natural frequency of the structure before and after the damage.Defining " generalized nearness degree " to solve the relative weights of thethree main load-bearing structure in steel truss tied arch bridge.4. For the monitoring data, an improved method is proposed by using the comprehensive direct method and the indirect method.Taking a steel truss tied arch bridge in Zhejiang province for an example to show the process of the evaluation of steel truss tied arch bridge.