I-39 over Kishwaukee River

Rockford, IL · 2019–2023

Client: Illinois Department of Transportation (IDOT) District 2
Owner: IDOT District 2
Location: Rockford, IL
Year: 2019–2023

I-39 over Kishwaukee River — Rockford, IL

Project Overview

Description

Twin bridge structures constructed in 1979 and 1980, spanning the Kishwaukee River and carrying Interstate 39. These are 'first-generation' post-tensioned precast concrete segmental bridges featuring five continuous spans with 156 single-cell segments, total length 1,190 feet center-to-center. The structures have been the subject of extensive research over forty years, particularly regarding shear cracking in girder webs.

HBM's Scope

Scope of Work

In-depth NBIS-level Inspection
Non-Destructive Testing (NDT) of superstructure concrete, internal post-tensioned bars, and external post-tensioning
Installation of Optical Fiber System with distributed sensors
Live load testing using two sets of four trucks
Structural Evaluation (FEM) Analysis
Development of a Load Rating Tool for Overweight Permit Vehicle evaluation
Bridge Condition Report
Existing structures S.N. 101-0133 (NB) & S.N. 101-0134 (SB) carrying Interstate 39 over the Kishwaukee River south of Rockford
Five continuous spans — three interior spans of 250'-0" and two end spans of 170'-0", totaling 1,190'-0" center-to-center abutment bearings; 156 single-cell precast post-tensioned segmental concrete box segments with a single shear key at each web
Roadway section: two 12'-0" traffic lanes, an 8'-0" interior shoulder, and a 10'-0" exterior shoulder; overall out-to-out width 42'-0"
'First-generation' precast post-tensioned segmental construction; segments erected by launching truss and balanced cantilever — the first bridges of their kind in Illinois and first constructed by means of a launching truss in the United States
Live load testing using two sets of four trucks, procuring multiple testing vehicles weighing upwards of 150,000 lbs

Highlights

Project Highlights

Comprehensive multi-phase evaluation assessing structural health through instrumentation with vibrating-wire strain gauges, crack meters, LVDT deflection systems, and fiber optics during static load testing
Forty-year retrospective evaluation of post-tensioned segmental construction

Recognition