Shear stress migration in a tapered girder with trapezoidal corrugated steel webs: Fid-Bau Portal

Shear stress migration in a tapered girder with trapezoidal corrugated steel webs

Zhou, Man / Su, Xiaolong

Abstract This study conducted a comprehensive investigation into the shear stress migration of a tapered prestressed concrete (PC) continuous box girder bridge with trapezoidal corrugated steel webs (TCSWs) throughout the entire construction process, including cantilever construction, structural system transformation and external prestressing tendon tensioning. The results revealed that the basic assumptions, which state that TCSWs bear all the shear force and that only the vertical component of the external prestressing contributes to shear stress when considering its contribution, are not valid for the shear design of tapered PC girder bridges with TCSWs. The horizontal component of the external prestressing and bending moments can cause additional shear forces via the Resal effect, which results in the migration of the shear stresses between the curved bottom concrete slabs and TCSWs. This study investigated the mechanism through which the Resal effect and external prestressing influence the migration of shear stress in the entire construction process. The results revealed that within continuous girders, the Resal effect exhibits both positive and negative implications. Specifically, the negative Resal effect exerts an unfavorable influence, resulting in an increase in the shear stress experienced by the TCSWs. Moreover, this study introduced a modified shear method that that takes into account the influence of bending moments and the horizontal component of external prestressing. In contrast to basic shear methods, this approach provides notably heightened accuracy.

Highlights • The Resal effect can induce the migration of shear stress between TCSWs and the bottom slab in tapered girders with TCSWs. • The Resal effect exhibits both positive and negative effects within tapered continuous girders with TCSWs. • The horizontal component of external prestressing can influence the migration of shear stress in tapered girders with TCSWs. • A modified method is proposed for calculating the shear stress on the TCSWs in tapered girders with TCSWs.