The Condition Assessment In Finished State Of Suspension Bridge Based On The Principal Component Analysis

Generally long span suspension bridge across the mountains and canyons, rivers, bays,etc. Its construction environment is poor and it has many structural components, many factors can affect the quality of construction. In the process of construction, construction errors inevitably occur, resulting in existing a certain deviation between its construction quality and its predetermined goals, namely construction quality variation. If the construction quality of error is too large, it will inevitably affect the safety of the state of suspension bridge. Currently,the cause analysis for construction errors of suspension bridge and the research about errors how to influence the bridge structure is less. In addition, lacking a direct and effective evaluation method for state of suspension bridge. Therefore, based on the establishment of an effective suspension bridge construction quality mutate into a state assessment method is very important. Based on the in-depth analysis of the causes and its influence of quality construction variation in all major suspension components in the process of construction.Using principal component analysis evaluates completed bridge safety performance status.Firstly, a mountainous area of Yunnan plateau sleet steel box girder bridge as the basis,by tracking survey the entire construction process, combined with field test data, construction records and test reports. In-depth analysis of anchorage system, the main tower, main cable,cable folders and other major steel box girder construction quality components to produce the type of variation, range and Genesis.Secondly, by establishing a finite element model, calculating and analysing the main component construction quality variation how to influence the bridge internal force and linear.The quantitative analysis of each component in the sensitivity of the internal force change on construction quality variation. The main study is the anchor connector declination affecting its safety performance; anchorage settlement deviation of the main cable and suspender internal forces, the main cable and linear change impacts steel box girder; the main tower of the tower leg vertical partial moment, the main cable and internal forces and boom girder, the main cable influence; influence and damage the main cable erection deviation of the main cable, internal force; rope clip deviation on the main cable, suspender internal force;steel box girder weight variation of the main cable main cable, boom influence internal forcesand the main cable and the influence of welding residual stress weld stresses. According to the degree of different mutations on construction quality for each component, we can obtain eight kinds of main types of construction quality Suspension variation.Finally, according to the construction quality of the main types of variation, selecting five safety evaluation index :the main tower of concrete tensile safety(T), the main cable safety(C), tensile safety boom(D), safety lever(L) and steel box girder stress safety(G) as suspension bridge safety evaluation. Principal component analysis method Comprehensive safety combined scores, to achieve a large-span suspension bridge to bridge the security status of quantitative evaluation. Research shows that comprehensive score values can comprehensively reflect the suspension bridge safety status and principal component comprehensive score is higher, the higher degree of safety. Therefore, evaluating the state of suspension bridge by principal component analysis is safe and reliable.