Study On The Dynamic Characteristics And Stability Analysis Of The Thin-walled Open Ribbed Arch In The Stage Of Swiveling Erection

With the span of reinforced concrete structure ribbed arch becoming longer, the research of dynamic property and stability characteristic according to swivel erection is much more important in theoretical significance and practicable significance.Taking Huajiang Bridge as the background, this paper discusses environment vibration measurement and model updating theory of long-span bridges. And the modal test and analysis of thin-walled open ribbed arch structure are proceed before structure swivel erection. It uses the real data to modify the model, which is used to structure stability analysis. And it has researched the improved of structural stability. The following work is done as emphases:(1)It discusses the modal test of long-span bridges according to ambient excitation, mainly discussing the mobile measurement used in modal test. And test point arrangement during vibration testing and the selection and placement methods of sensors are analysised.(2)Moving measurement was adopted to take modal experiment subject to ambient excitation about thin-walled open arch rib of Huajiang Bridge. It was obtained the dynamic properties of the swivel and dynamic monitoring data of upper rotary table on the stage of swivel erection and some future directions of research were proposed.(3)A practical model updating method had been introduced.This paper discussed the basic method of the finite element model updating, correctional parameter selection and establishment of the objective function. Correction method using parameter sensitivity, combined with field measured modal test data, had been applied in the model updating of thin-walled open arch rib of Huajiang Bridge. And an accurate calculation model had been obtained by modifying concrete elastic modulus and density of arch and elastic modulus and density of diaphragm steel skeleton with this method.(4)The modified model was adopted to analyse the stability of structure, and a practical method had been obtained for optimizing buckling eigenvalue of structure. This method can obtain the accurate sensitivity of the actual structure which is simulated through ANSYS Parameter Design Language. An optimization of buckling eigenvalue had been applied in the swivel body of Huajiang Bridge. A better performance of stability had been obtained by optimizing material distribution without significant change of structure weight.