The Stillwater Bridge Story Part 2: Design Revisions and the Future of Downtown Stillwater

September 5, 2016 at 7:24 pm | Posted in Bridges, Streets, and Highways | Leave a comment
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Now that the decision had been made to build the bridge, project development became more refined.

Aesthetic Treatments and Engineering Revisions

Bridge 12

Very early sketch from an internal Mn/DOT publication

Since the selection of an extradosed structure (is basically a hybrid of a girder bridge and a cable stayed bridge), the aesthetic design has also been refined since these alternate designs from 2005:

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2005 Rendering, “Organic” Design

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2005 Rendering “Hull” Design

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2015 Rendering “Portal” Design

Although not present in the very earliest concepts, three supports were thought necessary and included in initial designs.

Bridge 16

Later rendering showing center piers.

Bridge 172007 rendering switching to the buff color but still with center piers

As engineering advanced, design reduced the number back down to a pair of columns for each pier location, then one set of piers entirely, which lightened both the aesthetics and the construction costs. (The widely thrown out figure of $700 million has always been derived by taking the high side of initial estimates and rounding up). Despite spending an extra $6 million for the Minnesota approach work because the lowest bid wasn’t politically correct enough, overall costs have been revised downward several times as engineering advanced and as construction has progressed without incident and contingency funds are released.

The piers are designed to resemble reeds (although my sister said they looked more like tuning forks). Some visualizations show it as a stark white (and which may have been an early proposed finish), while it will actually be a duller buff color. My own theory is that buff was chosen as a compromise between blending into the sky, like a bright color would, and blending into the ground, like a darker color.

Bridge 18

Design showing buff color and reduced number of piers

Lighting will be Mn/DOT standard davit (curved top) poles rather than WisDOT standard trusses as seen on the Hudson Bridge. In keeping with the theme of “understated elegance” as I like to put it, there will be cool white LED accent lights inside the piers. Some roadway lighting will spill onto the south set of cables; a technicolor light show like I-35W or Lowry isn’t planned, although blank conduits are going to be installed to leave the option open in the future.

My opinion on the aesthetics is that although I like the way the bridge looks from the roadway, in profile the overall height of the bridge looks a bit too high relative to the cables. Part of me really wants to see a true cable-stayed bridge closer than the Great River Bridge in Burlington, IA and I’m not sure it would have been entirely inappropriate here. An extradosed bridge is already quite modern looking and there are many other man-made structures outside of the Saint Croix Valley, so I’m not clear about the objections to seeing the cable. But at the same time, it’s exciting to see one of the first extra-dosed bridges in the US. Despite periodic rehabilitation work, Duluth’s Blatnik Bridge won’t last forever and a contract to study its eventual replacement was let last year, so perhaps that will be where Minnesota’s first cable-stayed bridge will be built.

Some Roadgeek Trivia

The new bridge poses some interesting questions. MnDOT is, at least in theory, supposed to maintain all and only the highways as specified in the Minnesota constitution as the Babcock Amendment, later copied into Minn. Statutes §116.114, and those highways specified in later statutes, Minn.Stat. §116.115, §116.117, and §161.12. The present MN Highway 36 leading to the lift bridge being replaced is known legally as Constitutional Route 45, with the following description:

Beginning at a point on the west bank of the St. Croix River at Stillwater and thence extending in a southwesterly direction to a point on the easterly limits of the city of St. Paul, affording Stillwater, Lake Elmo, St. Paul and intervening and adjacent communities a reasonable means of communication, each with the other and other places within the state.

Therefore MnDOT is in theory legally obligated to maintain a trunk highway to the “west bank of the Saint Croix at Stillwater.” However, there are two series of “secret” trunk highways, the 800A series of highways MnDOT intends to maintain but does not mark, and the 900A series they maintain and want to get rid of such as Robert Street/MN 952A as a notable example. So the lift bridge will likely be designated with a 800A series number, say MN 836A. But it’s doubtful that the two blocks of Chestnut Street will continue to be a trunk highway, and may not even continue to be open to cars, so MN 95 will have to be close enough to the “west bank of the St. Croix” to fall under the requirement. In 2013, Legislative Route 339 was created as the formal number for the highway between MN 95 and the state line on the bridge. Also of note, MnDOT has simply ignored legal requirements in the past, for example those “Mr. Locally Important Person Memorial Highway” signs now need to be paid for by someone else, but in practice MnDOT would remove them if there was no outside funding sources even when they were theoretically obligated to maintain them.

What the Loop Trail Could have Been

Although the saving the lift bridge and the conception of the Loop Trail were two of the better results the project delays, the Loop Trail itself has a couple of major issues. First, there will be a gap in the trail in Houlton, Wisconsin, “filled” by shoulders on the old WI 35, and “Share the Road” signs on the old County E. As one of those people who won’t ride a bicycle on a road for any reason, I don’t care what the sign says or what the paint says, this is major problem for me.

Second, the west side along the river will be pleasant and the river bridges will be spectacular.  However, a large portion will be right next to the freeway with a 70 mph design speed in an area destined to become housing developments.  But in an alternate reality, it could have been built it along property lines on new alignment to the old County E. Beyond that point, the state of Wisconsin owns the property (shown in green) that could pull the trail away from freeway up to the bridge itself (this property was bought for the 1995 alignment).

Also of note, the properties in purple are publicly owned. The history of the land next to the DOT property along the river is unknown, but the ones on either side of the lift bridge are a former Stillwater city park that’s been closed for years. I sketched an idea for a pedestrian trail shortcut in brown, although I don’t know whether this is feasible or desirable. Another option to consider would be inquiring if the landowners might be interested in conservation easements as a buffer for the trail.

Bridge 19

Loop Trail in red, a better loop trail in yellow, possible pedestrian trail in brown

Some closing questions

Why the interchange at County E?

Although it seems odd to put the Wisconsin interchange at County E rather than the existing WI 35, there were really two reasons for that. The first is that it better serves the area east of Houlton and south of Somerset along County E, that’s already started to develop. The second reason is they wanted to discourage “inappropriate” development at the top of the bluff.

What about closing the bridge?

It was never studied, but the idea of just simply closing the bridge and not building a replacement has been brought up; in fact, in 2011 the city of Stillwater demanded that the bridge be closed. My opinion is that any dollars spent on highway projects are good, even if it might not have the highest benefit to cost of all the possibilities. But assuming all the dollars would transfer to other projects, it’s fair to ask what else we could do with $330 million. For example $237 million would rebuild the I-35W/I-494 interchange (Presumably Wisconsin would use its share to build a new north-south freeway east of Hudson to connect the WI 64 freeway to I-94). Perhaps the residents on the Wisconsin side, which is now mainly planned for residential, would want a Walmart and Applebee’s built near Houlton to replace the ones they can no longer easily access, so such a plan might backfire if the goal is to reduce the impact of development. Closing the bridge would cost $34 million a year in lost time.

Similarly, options to reduce traffic were studied and found to be ineffective. An origin-destination study indicates most weekday traffic is heading from Wisconsin to Stillwater or the northern suburbs with very little to downtown St. Paul and points convenient to I-94. And drivers are already avoiding the bridge at peak times to the extent practical so further attempts at reduction would be ineffective.

Bridge 20

Interesting graphic of where weekday bridge traffic comes from and goes from the 1995 Final EIS

Will history repeat?

It will be interesting to see what happens a generation from now. On the public bridge viewing cruise I went on, the DOT representatives were peppered with questions like “Why are you only building it four lanes wide?” and “Can it be expanded to more lanes in the future?” Official traffic projections are in the 40,000 range, which can still comfortably be handled by a four lane freeway, but 30 years later it’s obvious the New Cedar Bridge is inadequate, as is the Bloomington Ferry Bridge after 20 years. More likely in this case, I think the stoplights remaining on MN 36 will become a traffic apocalypse. Just like on sections of US 169 and MN 252, it was in large part the cities’ actions which caused interchanges not to be built initially. In both these cases, the cities changed their minds when they saw what a disaster traffic had become, so we’ll see what happens in Oak Park Heights.

There was already a 2013 request for the “Corridors of Commerce” grant funding that would have built an interchange at Osgood Avenue in Oak Park Heights, as well as at the four remaining signals west of Stillwater Blvd.  At least the Oak Park Heights intersections are being built with multiple turn lanes and flashing yellow arrows so capacity will be better than what it was.

The Downtown: Grow, Stagnate, or Die

The most obvious question with the future of downtown is what’s going to happen when 17,600 cars each day suddenly disappear. There’s plenty of examples of old traditional downtown that have been bypassed. Hopkins, Shakopee, Hastings, and Anoka come to mind, although US 169 still goes through Anoka despite years of efforts of local agencies north of the river to get a new bridge built there. None of these seem to be doing quite as well as downtown Stillwater, and downtown Shakopee is downright sleepy. The downtown buildings are certainly much more impressive than Hopkins, there are more of the types of stores to draw tourists, and there is the river. Shakopee has the river too, but it’s separated from downtown by the kind of wide suburban style roads that were once proposed to separate Stillwater, and frankly the Minnesota River isn’t as attractive.

There are some interesting statistics from the 1990s origin-destination studies. First of all, only 8% of the shoppers in downtown Stillwater are from Wisconsin. Of these, a large percentage are probably people that would continue to shop there anyway- the new bridge is only a couple of miles out of the way- and not impulse stops from through traffic. Second, of the cars that do not have a destination in the Stillwater area, only about 8%  stop (total 579 on weekdays and 464 on Sundays), and that includes anywhere in Stillwater, not just downtown.  That fits with my personal experience, when I’m stuck in traffic I’m not in the mood to make an impulse stop for an ice cream cone or an antique glass bottle and if I’m going to stop it will be at the McDonald’s.

Clearly the cars stopping in downtown that will now bypass it are small, relative to both the number already going through without stopping, and the overall shoppers already downtown. Periodically the bridge closes to be patched up or when it’s flooded out, and some of the businesses actually reported an increase in sales as residents weary of the incessant traffic started venturing out. Stillwater has already been Wal-Marted, so most of the “go pick up light bulbs” traffic has already left for the commercial strip.

Bridge 21

Typical Backup

Bridge 22

Imagine how much nicer downtown will be without these cars

I’d also throw out my opinion that the new bridge is probably the best option for downtown. A new bridge adjacent to the existing location would still bypass the core downtown, preclude the loop trail and severely impact or preclude the new parks south of downtown, and be a major new structure near the historic buildings blocking the view of the river (for navigation it would need to be 60 feet high). Closing the bridge would completely eliminate the possibility of through traffic stopping (even if not a lot of it does). Maintaining the existing bridge would result in it simply wearing out sooner rather than later and pedestrians still being restricted to the narrow sidewalk.

Downtown is being pro-active at preparing for change. Specific suggestions have been to highlight the old buildings with illumination, better signage illustrating local history, being aggressive in promoting new business opportunities, and filling empty holes in the streetscape.

The New Parks

Adjacent to downtown, an obvious improvement that will draw people will be new parks extending along the river both north and south. As mentioned before the 17 acre Bridgeview Park extends south from downtown almost to the new bridge. Now that the Terra-Terminal building has been demolished (as mandated by the Memorandum of Understanding mitigation), developing it into a visitors center and picnic shelter are no longer options. Instead focus is on building a municipal boat dock, additional parking and access, and a boat launch, as well as what to do with the Shoddy Mill buildings. They are a subject of a separate study. A restaurant would require too much parking even with the additional parking being built, so suggestions have been a coffee shop, bicycle shop, and a possible operations and maintenance facility for the boat dock. Development costs are estimated at $10.7 million over five phases. MnDOT is paying for about a third (paving the trails and constructing some accesses), the boat launch and dock are about half.

Future bicycle trail in Bridgview Park

Future bicycle trail in Bridgview Park

Shoddy Mill Buildings in their new home

Shoddy Mill Buildings in their new home

To the north, in 2014 the 15-acre Aiple property with a half mile of shoreline was purchased for $4.3 million. Planning is still in the preliminary stages, but I’d expect it to be left in a more natural state. Apart from the homestead itself, it’s a lot more natural than Lowell or Bridgeview Parks, where the more intensive uses will be accommodated and are more disturbed from past industrial use.

The Browns Creek and Gateway Trail Connections.

The 5.9 mile Browns Creek Trail has opened on the former Northern Pacific Railroad right of way that formerly went to White Bear Lake. For the first time it will offer bikers a gentle grade (2 percent) out of the valley. Linking up with the Gateway Trail and thus to downtown St. Paul, it is one of the most exciting additions, with an estimate of 75,000 users a year. Downtown Stillwater will have gone from “zero” to “a lot” of real bicycle trails (as defined as something more interesting than a multi-use path next to a wide suburban-style road) in a few short years.

Bridge 25

The Brown’s Creek Trail through the Aiple Property. In the hour I was there I saw dozens of users. This was the first really nice day it was officially open.

Bridge 26

New Stillwater parks (in green), the Browns Creek and Loop Trails (red) and the multi-use path along MN 36 (white).

Theoretically it would almost be possible to ride around the edge of Stillwater using portions of the Browns Creek, Loop Trails, and the unnamed new trails along the MN 36 frontage roads and along Manning Ave, but realistically it’s not a type of place one thinks of as a recreational bicycle trip, featuring some of the spectacular scenery shown below.

Bridge 27

Frontage Road trail

Restoring the Bridge

The current plan for the existing bridge is to have the bicycle trail down the center, with pedestrian paths on either side. The long-removed acorn lights will be replaced, supplemented with overhead lighting. The bridge will be returned to its original green color (it was repainted grey in WWII).

 

Surface Parking

One thing is evident: There’s a sea of lot of surface parking and a gasoline station between the historic buildings and the riverfront parks.

Bridge 28

A Sea of Parking

Bridge 29

Downtown Stillwater: Existing Surface Parking = Yellow; Existing and proposed bicycle trails = Red. Before I found the actual plan, I highlighted existing and my idea of potential structured parking in purple, which lined up closely with actual proposals.

There’s appropriate places for a sea of surface parking lots, but between a historic downtown and the riverfront parks is not the Shakopee Walmart. (Parking is such an issue that the city even has a specific parking committee.) The city is at least being realistic in that people are not going to park in some remote lot in Oak Park Heights and ride a slow bus downtown, so the plan is to replace it with structured parking that has street level retail along the 2nd Street north corridor that’s an easy walk from Main and the river.

In this map from the comprehensive plan, existing and proposed garages are outlined in blue. Having the city subsidize the garages to encourage people to travel downtown may preclude setting parking rates at what it actually costs, although developing some of the surface lots could help offset it. The uncertainty about where and if a new bridge would be built might be another reason the lots are still there. Recently the city has proposed charging fees for the remaining free lots, which has not gone over well with local businesses.

As for what will replace the surface lots, it’s unclear. North of the bridge, the plan for the surface parking east of the bicycle trail seems to be to add it to Lowell Park, but west of the trail I’ve seen various proposals to build structured parking on some of all or it, or else allow commercial development. (The 2004 North Main Street/Lowell Park Plan had the entire thing as a parking deck), a later parking study had a much smaller portion as a parking ramp, and the above graphic doesn’t mention any. From south of the bridge to Nelson Street the lots are mainly private, and don’t seem to be the subject of any plans. The southernmost lot will remain for parking for the new park, and as mentioned above, more paved parking for the park will be added.

Lane Removal

With the oncoming reduction in traffic, there is also opportunity for pedestrians to reclaim some of Main Street. There’s a current proposal that would convert Chestnut Street leading up to the bridge to a pedestrian mall, which means that the massive left and right turn lanes leading up to it would be completely unnecessary. It’s been confirmed that on the north side, at least, this space will go towards wider sidewalks, and I’d expect this to be discussed for the south side also.

Bridge 30

Uneeded Stilllwater Lanes

The Area Highway System

Thinking more broadly, it might also be time to start having conversations about the future of the highway system in the area, not just what gets built, but who owns it. Like is it still even appropriate for Main  Street to be a trunk highway? The long term goal is to have state ownership coincide with principal arterial status. Right now only MN 36 and I-94 are principal arterials, but 5, 95, and 96 are still trunk highways. At least in the short term transferring them all isn’t reasonable, considering there’s so many other dubious highways around. But I’d consider moving MN 95 onto Manning (which would require legislative approval since right now MN 95 must go through Bayport), and turning back existing MN 95 and MN 5. Manning is rapidly becoming the preferred major north-south route in the area, and there’s plans to rebuild the junction with MN 5 to favor north-south traffic, as well as expand Manning to four lanes in order to handle the anticipated 25,000 daily traffic volume. As Part One notes, this was actually proposed decades ago (although I certainly don’t think at this time the shortcut on new alignment north of MN 96 is needed.)

Bridge 31

Functional Classification Map

Time of course will be the ultimate judge, but personally think downtown has a very bright future.

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