Theoretical and Experimental Study on Natural Frequency of Externally Prestressed Box-Girder with Corrugated Steel Webs

Based on the characteristics of box girder with corrugated steel webs, the existing prestressing force, the effect of shear deformation of composite girder on the deflection, “folding effect” in longitudinal direction of corrugate steel webs and the arrangement of external tendons were considered comprehensively. With the experiment results of five literatures integrated,N/f_cA(the axial compression ratio) was selected as regression parameter to develop a regression equation for the effective cross-section stiffness of the girder. Then a formula for natural frequency of the externally prestressed box girder with corrugated steel webs was proposed. Finally, thein-situmeasurement on an actual bridge and a laboratory dynamic test on the model box girder with seven prestressing levels were conducted. The test results showed that the natural frequency of box girders with corrugated steel webs increased along with the growing external force. In contrast to other related formulas, the calculated results of the formula proposed in this paper showed the same tendency with measured results and the maximum error is 1%.