The I-35W Bridge Collapse 10 Years Later

August 1st, 2007 was Minnesota’s day of infamy, when one of the most heavily used bridges in the state collapsed into the Mississippi River. Looking back 10 years and a month later, it’s time to reflect on some of the changes since then.

It Ended the “Funny Money” Era at MnDOT

The 1990s were a time of stagnation for MnDOT. After the 1991 opening of I-394, meaningful investment in badly needed capacity expansion came to an end. The gas tax was raised in 1988, but was not indexed to inflation, so the impact continued to erode. The congestion problem worsened as metro lanes filled up, and more and more signals were put up on formerly free-flowing outstate expressways. The coming of the Jesse Ventura administration was a mixed bag, although it got the train rolling for light rail, as well as new enthusiasm for preserving outstate mobility with the “Moving Minnesota” and “Interregional Corridor” programs. At the same time a $189.00 cap on tab fees was instituted. The came the Tim Pawlenty administration. Lt Governor Carol Molnau was appointed commissioner of transportation and a culture of penny pinching arose.

It was questionable whether MnDOT should have spent $10,750 to bring in a keynote speaker to detail the rise and fall of Harley Davidson. Getting rid of such government waste and bloat is admirable, but the cheapskate attitude went beyond that and started affecting one of the core functions of government – building and maintaining transportation. To appease their suburban Republican voter base, Pawlenty and Molnau came up with all kinds of creative ways to shift money around to build high profile new roads without actually raising taxes.

The archetypal example of this was a bonding plan primarily for highway expansion, the 2003 Pawlenty-Molnau Transportation Finance Package To pay back the bonds, the proposal was to cut MnDOT staff, closing a large number of rest areas, and not painting stripes on state highways so often. One Democratic senator, whose name I unfortunately don’t remember, derided this all as “Funny Money” in a state transportation committee hearing.

Bonding for roads isn’t necessarily a bad thing. Government bonds are usually good investment risks and thus yield low interest rates, the interest is offset by eliminating construction inflation. And you reap the benefits of reduced crashes, smoother pavement, and reduced congestion immediately. But you must have a solid, appropriate funding source to pay it back.

Although the root cause of the bridge turned out to be a design flaw from the very beginning, a lot of wrath fell on MnDOT and the administration.  Democrats convinced enough Republicans to join in and raise taxes over a Pawlenty veto. The veto forced the money that Molnau didn’t want onto MnDOT, with the bulk of it directed at major structurally deficient bridges. Known as “Minnesota Law 2008; Chapter 152”, the law provided a sustainable revenue stream by eliminating the aforementioned cap on tab fees.  Secondly, it raised the state gasoline tax from 20 to 25 cents a gallon. The law directed that the money go to replacing structurally deficient bridges (known informally as “Chapter 152 Bridges”). Molnau was then fired by the state senate for not advocating for needed funding for the state’s transportation infrastructure.

It led the the replacement of countless structurally deficient bridges:

With the Chapter 152 funding, there was a crash program (pardon the pun) to replace the state’s structurally deficient and/or fracture critical bridges. They were divided up into tiers:

Tier 1. Consists of any bridge in the program that has an AADT > 1,000 and has a
sufficiency rating that is at or below 50; or is identified by the commissioner as a priority
project.

Tier 2. Consists of any bridge that is not a Tier 1 bridge, and is classified as fracture
critical, or has a sufficiency rating that is at or below 80.

Tier 3. Consists of any other bridge meeting the program criteria (structurally
deficient) that is not a Tier 1 or Tier 2 bridge.

The sufficiency rating is a scale of 0-100 graded 55% on the structural evaluation, 30% on the obsolescence of its design, and 15% on its importance to the public. Fracture Critical means that if a single minor part like a beam or a gussett plate fails, the whole bridge will also fail. Generally bridges were required to be replaced, but there were two exceptions:

A) The bridge is on the national register of historic places. In this case rehabilitation rather than replacement was allowed if it was feasible. There was a requirement that consideration be given to modifying the design to be non-fracture critical, but in no cases was this actually done due to impacting the historic status and/or not providing a 75 year design life in return for such a large investment.

B) The bridge is relatively modern. Engineers learned a lot about steel fatigue in the mid 1970s and started using better materials and construction techniques. The “New Cedar Bridge” built in the 1980s is an example. While more highway capacity and extending light rail across the river has merit, replacing the existing structure just because it’s technically fracture critical would be dumb since it’s in good shape and has many decades of service life left. Some routine maintenance was recently done which fulfilled the requirements of the program.

Some of the major bridges covered are as follows:

The Hastings Bridge. Although it was a scene of daily congestion and structurally deficient, it kept getting pushed farther back, up to the 2020s at one point, with the possibility of just keeping it, much to the chagrin of many people in Hastings. Although the structure was historic, it was opted to replace it rather than build a twin span and rehabilitate the old one for motor vehicles. Nor did the city of Hastings or Dakota County want the old one, so it was razed rather than preserved as a bicycle pedestrian structure. The bridge thus joined the spiral bridge in belonging to the ages.

The St. Croix Crossing was covered by the program (although replacement was in the works beforehand)

As was the Lafayette Bridge

And the Granite City Crossing in St. Cloud

Here’s a list of major bridges covered, italics are historic or relatively new bridges that are being rehabilitated rather than replaced.

• DeSoto Bridge (Now Granite City Crossing, MN 23 St. Cloud)
• Robbin-Drayton Bridbe (MN 11 over the Red River of the North)
• Hastings Bridge
• Lafayette Bridge
• Dresbach Bridge (I-90 at La Crosse)
• A number of I-394 at MN 100 and I-94 bridges
• St Peter MN 99 Bridge
• Cayuga Bridge
• New Cedar Bridge
• Stillwater Lift Bridge (Now the St. Croix Crossing)
• MN 243 Osceola Bridge
• Winona Bridge
• Sorlie Bridge, E Grand Forks
• MN 72 at Baudette
• US 61 at Red Wing
• US 14 at New Ulm

It Expedited the Orange Line.

People have been talking about transit along I-35W for a long time. There was a $1.2 billion proposal finalized 1993 that would have run light rail down the middle, between three general purpose and one HOV lane, would have redone a number of ramps, and taken out a row of houses along one side. (Reducing the general purpose lanes from 4 to 3 north of 46th was considered acceptable because it would eliminate the shock of the lane drop and all the substandard ramps, as well as light rail luring a number of suburban commuters that don’t like to ride buses.) This is why the HOV lanes in Bloomington were built as asphalt- they were supposed to be temporary until light rail came through.

Obviously taking that amount of right of way was not going to happen politically, nor was it politically possible to pay for something of that scale, and plans were dropped with the 1995 Met Council Transportation Policy Plan. Shortly after, the Richfield HOV lanes were built in 60 year concrete. But more modest transit was possible, and it took the Chapter 152 program to do something about it.

According to the law, all Tier 1 and Tier 2 bridges must be either addressed or under contract to be addressed by 30 Jun, 2018. Two bridges that you’ve probably noticed the decrepit condition of — northbound downtown exits to westbound I-94, and southbound I-35W over northbound downtown exits — are Chapter 152 bridges. Rather than just replace them as-is, the I-35W Access Project was formed to address these, as well as access desires of local businesses, and create a southbound lane and Lake Street station for the Orange Line. Although eliminating the weaves between Lake and 31st by moving the ramps to 38th St got dropped because of NIMBYS, and a plan to move the exit at Franklin was dropped presumably due to budgets it should be a substantial improvement.

We’re building an $50 Million Expressway for 4900 Vehicles a Day

Unfortunately the new law actually added in some wasteful projects. To lure in some Republican southwestern legislators to override the veto, a project was inserted to require Mn/DOT to finish building the MN 60 expressway. Traffic counts are 4900 for the middle and east segments, up to 6700 for the west.

It’s worth noting that 10,000 is the normal threshold where consideration is given to put additional lanes on rural highways. There’s some benefit for system continuity, reducing the strain of long distance travel, and economic development; after all, you can’t justify I-90 in Montana based on traffic volumes. But other constraints on the corridor limit the effectiveness as a shortcut between the Twin Cities and points southwest.

When I travel to the southwest I always found the slow speeds and traffic signals in Mankato and St. Peter a lot more obnoxious than the short, very lightly traveled two lane sections that are being upgraded. (Fixing these issues have been proposed but are a long ways down the road.) I much prefer the extra 15 minutes it takes to travel on freeway standard roads the entire way. But despite this extraneous project, from tragedy came new wherewithal to invest appropriately in Minnesota’s future.