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I-90 Mississippi River (Dresbach) Bridge

Donated by Ames Construction in cooperation with Minnesota DOT

Original Location: Over Mississippi River between La Crosse, WI, and Dresbach, MN     

Opened: October 1967

Replaced in 2016

Structure Type: Welded Plate Girder (Two-Girder Design)   

Total Length: 2,490 ft

Longest Span: 450 ft

Deck Width: 67.3 ft
Under Clearance: 62 ft

Deepest section: 21 ft 10 in

The MNDOT web page stated that although the current bridge had no weight restrictions and operated at an acceptable level of service, there were a couple of problems with the bridge and surrounding roadways that motivated its replacement.  Such as:

  • Current interchange geometry created difficult and unsafe traffic movements for commuter traffic.

  • Bridge structural deficiencies – had no structural redundancy (that could be accounted for by current guidelines); portions were beyond useful life; fatigue cracking had occurred

  • Narrow bridge shoulders – did not meet state/federal standards; no emergency vehicle bypassing or stalled vehicle storage

  • Traffic buildup during parts of the day

  • Traffic safety concerns – I-90 curve had higher crash rate; northbound Hwy 61 to eastbound I-90 had pattern of crashes

  • Riverfront access – no access to riverfront from southbound Hwy 61; no access to riverfront from eastbound I-90

  • I-90 as regional river crossing – nearest crossings are five miles south and 24 miles north

The bridge specimens donated to S-BRITE showcase simple and effective retrofits that were performed at the intersection of welds on the lateral gusset plate details.  This retrofit was most likely performed following the fracture of a girder on the Lafayette St. Bridge near St. Paul Minnesota in 1975.    

Figure 1. I-90 Mississippi River Bridge before demolition (Source: MNDOT)

 

Figure 2. Elevation view showing 21'-10" tall haunched section of the main girders (Source: MNDOT)

 

Figure 3. View showing floor system on the two-girder design (Source: MNDOT)
 
Figure 4. Dresbach girders and lateral gusset plate details at S-BRITE Center 

 

Figure 5. Dresbach pin & hanger detail being used at S-BRITE during professional training course
 

Historic Documents:

1964 Dresbach Design Drawings