Lansing, IA new Mississippi bridge

[triplemultiplex]

I was genuinely surprised to learn that a new bridge over the Mississippi River at Lansing, Iowa is going to be a cantilever truss bridge.

https://iowadot.gov/lansingbridge/New-Bridge-Design-Overview



I associate this style bridge with a bygone era in the mid 20th Century when steel was cheaper and function over form was the order of the day.  I am not aware of any recent bridges of this style being built.  Perhaps others are? 
All recent new bridges over the upper Mississippi have been like cable arches or cable stay spans.  Or just boring viaducts (like the recent new bridge for I-90).  So it's interesting to see them go with a 'retro' design for this minor crossing.

[Big John]

A lot of reasons that new truss bridges are rarely built is that any expansion is very difficult, and moreover so that they are fracture critical making them more susceptible to collapse.

[Rothman]

A lot of reasons that new truss bridges are rarely built is that any expansion is very difficult, and moreover so that they are fracture critical making them more susceptible to collapse.

Gussetless trusses are safer than the old trusses with gusset plates.  NYSDOT is building one starting this summer north of Syracuse -- US 11 over Oneida Lake.  State Historical Preservation Office required a truss to replace the old truss.

[froggie]

I was genuinely surprised to learn that a new bridge over the Mississippi River at Lansing, Iowa is going to be a cantilever truss bridge.

Q: Is the bridge at Lansing historic?

    A: Yes, the Iowa DOT determined the current bridge at Lansing eligible for the National Register of Historic Places in 1995. The Iowa State Historic Preservation Officer agreed and confirmed that determination in 2016. This historic designation helped drive the design of the new bridge to closely resemble the old bridge.

[TheHighwayMan3561]

A new bridge would cost far less over time than a major retrofit of the existing Black Hawk Bridge.

The "don't replace" option also wasn't feasible because the nearest adjacent crossings are 40 miles in either direction at La Crosse to the north and Prairie du Chien to the south.

[JREwing78]

A lot of reasons that new truss bridges are rarely built is that any expansion is very difficult, and moreover so that they are fracture critical making them more susceptible to collapse.

It's highly unlikely traffic on this new bridge would ever reach a point that requires widening. Lansing, IA has fewer than 1,000 residents. A Kwik Star is probably the closest to a commercial chain establishment it has. The nearest emergency room is in Waukon, IA, about 25 miles away via twisting back roads. Ditto for the nearest Dollar General. The nearest McDonalds or Culver's is 30 miles and 45 minutes away. Suffice it to say that Lansing is an isolated town.

I am disappointed that there wasn't more consideration made for pedestrians and bicyclists. The 8-foot shoulders on each side are fine, but there's no guardrail or anything else to separate vehicle traffic from pedestrians or bicyclists. At the planned posted 25 mph speed limit, maybe that's not strictly necessary.

[triplemultiplex]

At the planned posted 25 mph speed limit, maybe that's not strictly necessary.

I assume that's cuz they don't want traffic to pick up a head of steam coming into Lansing.

[Big John]

The current bridge is indefinitely closed until a thorough inspection can be done to determine its structural integrity.

[JREwing78]

The current bridge is indefinitely closed until a thorough inspection can be done to determine its structural integrity.

That's disconcerting. Construction on the new span has been underway for a few months now.

https://www.wxow.com/news/top-stories/iowa-dot-lansing-bridge-closed-due-to-slight-movement-of-the-bridge/article_305ecbfe-d42d-11ee-a93a-1b98e7d100a4.html

[Big John]

The inspection found movement in 2 piers. Stabilization efforts have begun but the bridge could be closed for up to 2 months.

[triplemultiplex]

Damn, should've started the new bridge a year earlier.

[JREwing78]

Damn, should've started the new bridge a year earlier.

I doubt it would have mattered. The piers didn't suddenly start moving until construction on the piers for the new bridge was underway.

[JREwing78]

The fix for the (old) Lansing bridge: pull out the bridge deck, replace the existing piers with new steel ones, and then put the bridge deck back.

Meanwhile, Iowa's DOT is working on a water taxi and van pool for folks who need to make the crossing.

Work underway to repair Mississippi River bridge at Lansing
https://www.radioiowa.com/2024/03/08/work-underway-to-repair-mississippi-river-bridge-at-lansing/