Frequency study on improved composite box girder bridges with corrugated steel webs

This study proposes a method to analyze the dynamic characteristics of an improved composite box girder bridge with corrugated steel webs (ICBGBCSW). In this study, a theoretical analysis was first conducted. By comprehensively considering temperature, shear deformation and stiffness correction, the natural frequency formula of simply supported ICBGBCSW was derived based on the stress equivalence principle. The accuracy of the proposed frequency formula was verified through the finite element results and measurement results of the simply supported ICBGBCSW in the field. Then, sensitivity studies were performed to investigate the effects of the temperature -equivalent axial eccentric force, elastic modulus change, shear deformation, height -span ratios, and width -span ratios on the natural frequency of the ICBGBCSW. Finally, the natural frequency formula of continuously supported ICBGBCSW was derived by applying the three bending moment equations, and the fundamental frequency formula of continuously supported ICBGBCSW was proposed. The proposed method is able to consider both the influences of temperature, shear deformation and stiffness correction and has good performance in analyzing the natural frequency of the ICBGBCSW. This study provides a technique support for the modification of the fundamental frequency formula of the ICBGBCSW in the current code, and provides a reference for the analysis of dynamic characteristics and design of the ICBGBCSW.