ABSTRACT
Under the bending-shear condition, the diagonal crack of web will appear in concrete box-girder bridge when principal tensile stress of tensile-shear zone concrete exceeds principal stress limit value. The overall objective of this study is to develop a calculated method for the fatigue behavior of web under bending-shear of concrete box-girder bridge. First, some basic conceptions and calculation methods of concrete fatigue theory are introduced. Next, the time-history curves of bending moment, shear force and principal tensile stress in typical section have been achieved. Then the effects of vehicle speed and heavy vehicles for the equivalent principal tensile stress on web of box-girder are discussed. Finally, the reliability index is established to assess the fatigue life for existing concrete box-girder bridge. Some conclusions are drawn on the basis of the current research.
