Jane Addams Tollway I-90 Bridges over the Kishwaukee River - New standards for Integral Abutment Bridges

Integral Abutment Bridges (IAB) are widely adopted in the United States. The Federal Highway Administration (FHWA) and State Departments of Transportation are developing new design criteria based on temperature range, total length, material types, soil and foundation types and skew. The goal is to gain a more detailed knowledge of the behaviour of this type of bridges to support the increasing use of them.

This case study relates to two bridges for the Illinois Tollway that were designed while the Illinois Department of Transportation was in the process of developing new design guidelines for IAB. One of the project goals was to create a prototype to test the new standards and details. The design was developed in coordination with a research group that received a grant to instrument the bridge and collect data to study the behaviour of substructures and superstructures of long integral abutment bridges. The paper discusses the state-of-the-art of IABs in the United Sates and provides insight on what are the major issues that designers have to focus for future applications.