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HYDRAULIC EVALUATION
OF NEW OR RECONSTRUCTED BRIDGES OVER THE CHICAGO WATERWAYS Primary Investigator: Dr. Charles S. Melching Sponsor: Chicago Department of Transportation through consultants When any structure is built such that it blocks or changes
the hydraulic geometry of the floodway a hydraulic evaluation must be done to
estimate the change (usually an increase) in water-surface elevation because
of this construction. In Illinois
increases in water-surface elevation more than 0.1 feet for the 1 percent
chance exceedance (100-year) flood are not allowed and the structure must be
redesigned such that the increase is less than or equal to 0.1 feet. In the Chicago Waterway System (CW) during
high flow (flood) periods the flows and water-surface elevations throughout
the CWS are controlled by the opening of the sluice gates and turbines at the
Lockport Powerhouse and the Lockport Controlling Works (2.2 miles upstream
from the powerhouse). When the sluice
gates and controlling works are opened the water-surface elevation at
Lockport drops increasing the water-surface and energy slopes throughout the
CWS, and, thus, increasing flows through the CWS. Therefore, in order to determine the
water-surface elevation at a bridge site it is necessary simulate the flows
into and through the entire CWS not just upstream of the bridge site as is
typical of most bridge hydraulic analyses.
The DUFLOW model of the CWS developed at The bridges evaluated include: The Reconstructed Consultant: H.W.
Lochner, Inc., Chicago, Duration: April
2004-July 2006 Funding Level:
$14,090 The Proposed Bridge
over the South Branch of the Chicago River at Taylor Street Consultant:
Parsons Transportation Group, Chicago, Duration: February
2005-present Funding Level:
$7,907 The Reconstructed Bridges over the North Branch Canal and Chicago River at Division Street Consultant: Earth Tech Duration: November 2005-present Funding Level: $7,907
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