Shear hysteresis effects in concrete box girders with simply supported butterfly webs

The butterfly web concrete box girder represents an innovative bridge structure characterized by a hollow butterfly web design. This structure is noted for its lightweight nature, reduced maintenance costs, and abbreviated construction timelines. To investigate the distribution of the shear hysteresis effect, a test beam model of the butterfly web was conceptualized and constructed. Subsequently, static loading tests were conducted, and a corresponding ABAQUS finite element model was developed to align with the experimental conditions. Utilizing the principle of section equivalence, a calculation method for the moment of inertia (Ik) at the hollow web of the box girder was proposed. Furthermore, a formula for determining the shear hysteresis effect of the butterfly web box girder was established through the application of the energy variation method. The findings from the experimental, finite element, and theoretical analyses indicate that the shear hysteresis effect at the hollow web of the butterfly web box girder surpasses that of the solid web. Additionally, the shear hysteresis effect is most pronounced at the intersection of the web and the top plate, diminishing progressively towards the edges. The shear hysteresis effect is also more significant at the supporting and span sections of the box girder. The longitudinal stress values derived from the variational method exhibit an error range of −2.4% to 7.4% when compared to test values under concentrated loads, and a similar error range of −2.4% to 7.4% when compared to finite element values under uniform loads. The discrepancies between the longitudinal stress values and the finite element values range from −2.7% to 3.8%, thereby validating the accuracy of the proposed formula. The outcomes of this research may serve as a valuable reference for the design of butterfly web box girders.