Effect of cyclic thermal loading on the performance of steel H-piles in integral bridges with stub-abutments

摘要

In this paper, analytical equations are developed to estimate the lateral displacement capacity of steel-H piles in integral bridges with stub abutments subjected to cyclic thermal variations. First, steel H piles that are capable of sustaining large plastic deformations are identified based on their local buckling strength. The normalized moment-curvature relationships of these piles are then obtained for various axial load levels. Next, a low-cycle fatigue damage model is employed to determine the maximum cyclic curvatures that such piles can sustain. The obtained moment-curvature relationships and cyclic curvature limits are used in static pushover analyses of two steel H-piles driven in soil to obtain the maximum thermal-induced cyclic lateral displacements such piles can sustain. Using the pushover analyses results, the displacement capacity of steel H-piles are formulated as a function of piles properties, soil type and stiffness. Based on the obtained pile cyclic displacement capacities, the maximum length limits for integral bridges subjected to cyclic thermal variations are calculated. It is found that the maximum length limit for concrete integral bridges ranges between 150 and 265 m in cold climates and 180 and 320 m in moderate climates and that for steel integral bridges range between 80 and 145 m in cold climates and 125 and 220 m in moderate climates.