Curved Steel I-Girder Bridge Response during Construction Loading: Effects of Web Plumbness

Horizontally curved steel I-girder bridge systems tend to deflect and rotate out of plane under the action of gravity. Oftentimes, this response will lead to a condition wherein the subsequent girder cross-sectional orientation is one where the web is out of plumb. Currently, there exists little guidance concerning what effect this web out of plumbness has on structural performance. As a result of this lack of guidance from design specifications, there is tendency within current practice to work to alleviate the out of plumb condition through various detailing and erection strategies, since the performance implications of its presence within the structure are poorly understood. The present research employs nonlinear finite-element modeling strategies to study the various effects that web out of plumbness has on flange tip stresses, vertical and lateral deflections, cross-sectional distortion, and cross-frame demands. The focus of the present work is the construction stage, and thus steel dead load is the governing loading condition treated. Web out of plumbness magnitudes of up to 5° are considered.