Study On Natural Vibration Properties Of The Thin-walled Beam Bridges

With the rapid development of transportation industry of China, the span and width of thin-walled beam bridge are also gradually increasing. The research and analysis of its mechanical behavior are paid more attention by the scholars. Especially, the research of the shear lag effect becomes a key content. The shear lag effect will make the local stress of the thin-walled beam section concentrate and the bridge deflection and natural vibration properties change. Then, the reliability and security of thin-walled beam structure will decline, and affect its normal use. In order to show the thin-walled beam structure’s influence of the dynamic characteristics with the shear lag effect problem, therefore, the structure Natural vibration frequency of the thin-walled beam bridge under considering the shear lag effect was analyzed and researched based on the thin-walled structure theory and Hamilton dual systems.The paper abandoned the flat section assumption and Kollbrunner-Hajdin’s theory which in the thin-walled beam theory. The connection displacement is the basic displacement function, and the linear interpolation was applied to describe the longitudinal displacement of the cross-section points in box cross-section and I shape cross-section. The Hamilton equation of the structure Natural vibration frequency of the thin-walled box beam under considering the shear lag effect is derived based on the Hamilton dual system. The precise integration method and Matlab software are used to determine the high precise numerical solution of the equation. The method proposed is applied in the specific example to verify its science and reasonability by comparing and analyzing.