Verification of Bridge Foundation Design Assumptions and Calculations

Abstract

The Sagamore Parkway Bridge consists of twin parallel bridges over the Wabash River in Lafayette, IN. The old steel-truss eastbound bridge was demolished in November 2016 and replaced by a new seven-span concrete bridge. The new bridge consists of two end-bents (bent 1 and bent 8) and six interior piers (pier 2 to pier 7) that are founded on closed-ended and open-ended driven pipe piles, respectively. During bridge construction, one of the bridge piers (pier 7) and its foundation elements were selected for instrumentation for monitoring the long-term response of the bridge to dead and live loads. The main goals of the project were (1) to compare the design bridge loads (dead and live loads) with the actual measured loads and (2) to study the transfer of the superstructure loads to the foundation and the load distribution among the piles in the group. This report presents in detail the site investigation data, the instrumentation schemes used for load and settlement measurements, and the response of the bridge pier and its foundation to dead and live loads at different stages during and after bridge construction. The measurement results include the load-settlement curves of the bridge pier and the piles supporting it, the load transferred from the bridge pier to its foundation, the bearing capacity of the pile cap, the load eccentricity, and the distribution of loads within the pier’s cross section and among the individual piles in the group. The measured dead and live loads are compared with those estimated in bridge design.