The Method Of The Defect Condition Of Evaluation Scheme And The Prediction Of Residual Life Of The Cable-stayed Bridge

The large bridge is based on bridge health monitoring system. It is particularlyimportant to identify and assess the damage of structures, to predict the remaining lifeand understand the actual running state of the bridge structures which is related topeople’s life and property security.This paper is based on the research status of bridge damage identification andevaluation method at home and abroad, which also is regarded the long-span concretecable-stayed bridge equipped with the health monitoring system as the background. Theidentification and assessment of major disease damage and the prediction of remaininglife of structures are studied, the details are as follows.①Make the statistical analysis of the cable-stayed bridge existed disease and classifythe main disease and the causes of the cable-stayed bridge, as a theoretical guide for theprevention of various diseases.②Taking Wujiang bridge as the engineering background, establishing the finiteelement model, analyzing the dynamic characteristics of the bridge. The results showthat the frequency value is small and mode is very dense of the bridge. The dominantmode of each order is also analyzed. The new method is proposed. According to themechanical symptom database of corresponding damage, conversely, thecomprehensive utilization of non deterministic index is used to diagnose the injury, toidentify the damage location and the damage degree. By using the AHP method todetermine the weight of underlying index, the degree of important value in the matrix isdetermined which is based on the sensitivity to damage mechanical symptoms, and theweight value of each mechanical symptoms to identify the damage is determined.③Using the method of reducing stiffness in finite element to simulate the damage ofcable and concrete girder unit and using the method of reducing stiffness proportion tosimulate the damage to analyze all the mechanical indexes of whole bridge after damage.The results show that the change of the cable force near the failure cable, the stresschange of failure cable and girder in anchorage zone, the stress change of Pylon whosecable is failure and the longitudinal displacement are more sensitive to cable failure. Butthe frequency of bridge deck system and the deflection of beam are very small. Themodal curvature and the stress change of beam are more sensitive to the girder damage.But the frequency of bridge deck system and the deflection of beam are very small. ④To predict the residual life of bridge by using the prediction method Mark offprocess. The core of this method is to determine the initial stat probability distributionvector and transfer probability matrix. Basing on a large number of data of healthmonitoring system, using the method of probability and statistics to determine the initialstate probability distribution vector and using the method of inverse matrix solvetransition probability matrix.