Steel truss bridges with welded box-section members and bowknot integral joints, Part I: Linear and non-linear analysis

The first part of the papers focuses on linear and non-linear analyses of a typical Warren steel truss bridge consisting of welded box-section members and bowknot integral joints. The truss studied is simply supported at two end nodes of bottom chords with two concentrated dead and live loads being applied at each unsupported bottom chord node. The finite element method (FEM) was employed to analyze the elastic and elasto-plastic behaviors of trusses with bowknot/conventional integral joints. The results show that the secondary moments at the member ends and the sectional maximum stresses of the un-shrunken segments of the truss are significantly reduced by the section-shrinking of the member ends, but the vertical stiffness and elastic stability of the bowknot truss are deteriorated compared to the conventional one. When the steel strength of the shrunken segments has been moderately enhanced, the ultimate bearing capacities of axially compressed shrunken members and of Warren trusses with bowknot integral joints are as high as those of uniform members and of conventional trusses, respectively.

► We proposed innovative bowknot integral joints for steel truss bridges.
► We investigated structural behaviors of Warren trusses consisting of such joints.
► Secondary moments at member ends are notably reduced by adopting bowknot joints.
► Ultimate bearing capacity of bowknot truss could be as high as the conventional one.