Flexible Pile Head in Jointless Bridges: Design Provisions for H-Piles in Cohesive Soils

Abstract

Several methods are used to increase the lateral displacement capacity of the piles supporting jointless bridges, the most effective of which are predrilled holes and a flexible pile-cap connection. Depending on soil type and required displacement capacity, these two methods can be combined. This paper discusses a simple study carried out to demonstrate the efficiency of the flexible-head condition, and a finite-element analysis conducted on a prestressed pile. The model was first calibrated with the test results, and then a flexible detail was applied to the model. The results of this part of the study show that a flexible connection can increase the displacement capacity of embedded piles. Finally, nonlinear analyses were conducted using simulation software for compact HP piles. The results of these analyses revealed that strong axis bending results in larger displacement capacity compared to weak axis bending, although the stiffness is smaller in the latter case. Provisions are also developed to account for partial fixity. The paper concludes by providing design provisions for H-piles for the application of a pinned head detail that will allow the use of jointless bridges in conjunction with longer bridge lengths.