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You are here : eLibrary : IAHR World Congress Proceedings : 33rd Congress - Vancouver (2009) : Topic A: Advances in the Fundamentals of Water Science and Engineering : Hydraulic and scour analyses for the i-35w bridge replacement over the mississippi river
Hydraulic and scour analyses for the i-35w bridge replacement over the mississippi river
Author : L.W. Zevenbergen£¨1£©, D.W. Robinson£¨2£©£¬P.F. Lagasse£¨3£©
On August 1, 2007, the I-35W bridge over the Mississippi River in Minneapolis,
Minnesota, failed catastrophically, killing 13 people and severing a vital link in the
Minneapolis-St. Paul transportation network. As cleanup was underway and
investigators searched for the cause of the collapse, the Minnesota Department of
Transportation (Mn/DOT) began to focus on rebuilding, knowing how critical it was
that traffic flowed smoothly as soon as possible. Ayres Associates performed the
hydraulic and scour analyses for the replacement bridge as part of the design team led
by Figg Bridge Engineers for Flatiron-Manson, on this design-build project.
Even though the extremely aggressive construction schedule required the hydraulic
analysis be completed in less than three weeks, Mn/DOT required two-dimensional
(2-D) numerical modeling in addition to the standard HEC-RAS modeling for ¡°No-
Rise¡± certification. Several factors dictated the use of 2-D modeling. The I-35W
bridge is immediately downstream of a Mississippi River lock and dam. During
extreme floods the distribution of flow may vary depending on the operation of the
lock chamber and gates. As a result the flow distribution at the bridge also varies.
Mn/DOT also required that there would be no adverse hydraulic or scour impact on
the 10th Avenue bridge located immediately downstream of the I-35W bridge. A
downstream impact can only be assessed through 2-D modeling. Other potential
impacts were also evaluated at two major storm tunnel outlets located at the crossing.
This paper highlights the results of the two-dimensional modeling that provided
detailed information on hydraulic conditions throughout the bridge reach and
demonstrated that the new bridge would not adversely impact other structures. The 2-
D modeling was also used to determine the scour potential for the new bridge design.
File Size : 1,461,664 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 33rd Congress - Vancouver (2009)
Article : Topic A: Advances in the Fundamentals of Water Science and Engineering
Date Published : 21/08/2015
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