Research On Identification Of Damaged Hanger And The Sections Of Anchoringcables Of Suspension Bridges Based On Monitoring Of Long-Span Pre-Stressed Steel Structure

Aiming at the problem of suspend-dome structural health monitoring and damage identification of long-span pre-stressed steel structure,the research object of this paper is the finite element model of a suspend-dome structure,based on the linear hypothesis and multi-objective optimization algorithm,extracting and analyzing the data(including internal force,strain)of the key bearing component(e.g.,strop,poles)in the suspend-dome structure by calculating,thus identifying the strop-element damage of the long-span pre-stressed steel structure(suspend-dome structure),studying applicability of this method,using in the structural health monitoring of long-span pre-stressed steel structure,providing a theoretical basis for the structural health monitoring and damage identification of this type of long-span pre-stressed steel structure.The main research work of this paper includes the following aspects:(1)The finite element model of a Kiewitt suspend-dome structure,acrossing 40 meters,was established and analyzed,and than the sectional dimension and the designed cable prestress of the Kiewitt suspend-dome structure was modified iteratively,meanwhile the intial stress was applied to structure in the form of initial strain,based on the stress condition by the finite element simulation and optimization theory of the suspend-dome structure prestress.(2)On the basis of the existing finite element simulation data of the Kiewitt suspend-dome structure,the correctness of the linearity hypothesis suitable for suspend-dome structure was verified by examining the hypotheses.Furthermore the damage of the key bearing component(90 strop units)of suspend-dome structure was identified accurately,based on the multi-objective algorithm Research shows that the damage degree and damage linear error relative with cable force of cable has gradually become larger,once the damage degree of ring cable element was below 40%.the relative error of ring cable cable force vector shows that the linear relationship hypothesis can be guaranteed under the accuracy(most elements linear error vector are lower than 15%)investment the suspendome research use,and when the degree of injury was 40%and above,the linear error growth damage identification significantly accelerated the linear error.alinear error vector values of most elements of 25%individual cases,of which maximum error reaches 45%.In addition,the larger the cable force,the larger the linear error of the damage identification of the corresponding cable.(3)Research of the paper has shown that,based on the linear hypothesis and multi-objective optimization algorithm,the damage location and damage degree could be identified accurately in the structural health monitoring of suspend-dome structure,through the use of linearity hypothesis,when the number of damaged strop of suspend-dome structure reached about half(50)and the degree of the damage reached 40%.The damage of strop could be identified well,when the degree of the damage is within 40%.But error would exist in part of identification of the damage location and damage degree,when the number of damaged strop of suspend-dome structure exceeded 60 and the degree of the damage exceeded 40%.As the number of damaged cables increased gradually,in the same ring cable damaged cable identification results of local strong correlation,and this is in the same position of the ring cable cable damage identification results to be similar,different ring cable damage to the unit identification results significantly different.The above shows that the linearity hypothesis and the multi-objective algorithm can be well applied to structural health monitoring and damage identification of suspend-dome structure according to the variation of cable force.