Category Archives: Bridges

I-5 Bridge over the Skagit River collapses in Washington State

This is breaking news, and this blog post will be out of date.

The Interstate 5 bridge over the Skagit River has collapsed near Mount Vernon, Washington. A map shows where the incident happened, about half way between Seattle and the Canadian border.

As of this writing there are no confirmed details about the cause of the bridge collapse. The Seattle Times says it may have been because an oversized truck hit the bridge with its load. Three people were rescued from the water with minor injuries.

Some sources:

Scanner, via Broadcastify: Skagit County Police and Fire.  4400+ listeners at 8:19 p.m. 5/23/13. This is the initial police response, via Soundcloud and Alertpage.


Skagit Valley-News: Reports: Bridge collapses between Mount Vernon, Burlington

The I-5 Skagit River Bridge is a through-truss bridge that was built in 1955, according to the website It is the same basic type of design of the Interstate 5 Bridge over the Columbia River in Vancouver, according to the site.

Associated Press: I-5 bridge collapses in NW Wash.; people in water. I-5 Skagit River Bridge. Includes maps and photos of bridge.

National Bridge Inventory Database details follow, from The structural evaluation is "Somewhat better than minimum adequacy to tolerate being left in place as is".

State: WA
Place Name: Mount Vernon
County: Skagit
NBI Structure Number: 0004794A0000000
Route Sign Prefix: Interstate
Route Number: 5
Facility Carried: I-5
Feature Intersected: SKAGIT RIVER
Location: 0.7 N JCT SR 538
Year Built: 1955
Status: Functionally Obsolete
RecordType: Roadway is carried ON the structure
Level of Service: Mainline roadway
Owner: State Highway Agency
Highway Agency District: 01
Maintenance Responsibility: State Highway Agency
Functional Class: Principal Arterial – Interstate, Urban
Service On Bridge: Highway
Service Under Bridge: Highway-waterway
Latitude: 48 26 35.80 N
Longitude: 122 20 27.90 W
Material Design: Steel
Design Construction: Truss – Thru
Approach Material Design: Concrete continuous
Approach Design Construction: Tee Beam
Structure Length (m): 338.9
Navigation Vertical Clearance (m): 2.4
Approach Roadway Width (m): 21.9
Lanes on Structure: 4
Lanes under Structure: 4
Average Daily Traffic: 70925
Year of Average Daily Traffic: 2010
Design Load: MS 18
Scour: Bridge foundations determined to be stable for assessed or calculated scour condition.
Bridge Railings: Meet currently acceptable standards.
Historical Significance: Bridge is not eligible for the National Register of Historic Places.
# of Spans in Main Structure: 4
# of Spans in Approach Structures: 8
StructureFlared: No flare
Transitions: Does not meet currently acceptable standards.
Approach Guardrail: Meets currently acceptable standards.
Approach Guardrail Ends: Not Applicable
Navigation Control: Navigation control on waterawy (bridge permit required).
Navigation Horizontal Clearance (m): 33.5
Structure Open?: Open, no restrictions
Deck: Satisfactory Condition
Superstructure: Fair Condition
Substructure: Satisfactory Condition
Structural Evaluation: Somewhat better than minimum adequacy to tolerate being left in place as is
Sufficiency Rating (%): 57.4

 News coverage – this may change as time progresses:

KING 5 live coverage.

KIRO 7 live coverage.



E. Stadium Bridges Dedication Ceremony is Tuesday, May 14, 2013 at 10 a.m.

Press release from the City of Ann Arbor


E. Stadium Bridges Dedication Ceremony is Tuesday, May 14, 10 a.m.

ANN ARBOR, Mich., April 11, 2013 — A brief dedication ceremony for the City of Ann Arbor’s E. Stadium Bridges Replacement Project will be held at 10 a.m., Tuesday, May 14, 2013 near 1501 S. State Street, next to the E. Stadium Boulevard Bridge over S. State Street. Congressman John Dingell will be joined with representatives from the national Department of Transportation, as well as officials from MDOT, Washtenaw County, City of Ann Arbor, project contractors, neighbors, and the general public. Temporary public parking will be available on the UM Red Lot adjacent to the bridge over S. State Street.

Within 12 months, the E. Stadium Bridges Reconstruction Project built two new bridges, on-street bike lanes, a new sidewalk on the south side–and a widened sidewalk along the north side–of E. Stadium Boulevard, a new sidewalk along the west side of S. State Street with a signalized pedestrian crossing of the railroad tracks, two staircases connecting E. Stadium Boulevard to S. State Street, ADA-compliant facilities with an accessible path between S. State Street and E. Stadium Boulevard, storm water quality
improvements, new water mains, improvements to Rose-White Park, landscaping, and many other features.

The City of Ann Arbor received funding from the United States Department of Transportation (USDOT) for $13.9 million in TIGER II Discretionary Grant Funding, and about $1.67 million and $1.20 million, respectively, in Local Bridge Program and Transportation Enhancement Funding. All told, the City received about $16.8 million (or about 73 percent of the total estimated project costs) in state and federal funds to complete the project. The remaining 27 percent of the project was funded via various city sources including the Ann Arbor voter-approved Street and Bridge Resurfacing & Reconstruction Millage as the required local-match for the grants. Public notifications of developments in the E. Stadium Bridges project have been posted at

The previous E. Stadium Bridges were built in 1928. The bridges carry more than 24,000 vehicles per day.

Visit the Ann Arbor Bridges website:
Follow project updates on Twitter:!/AnnArborBridges
Become a fan on Facebook:

Stadium Bridges to reopen!

Ann Arbor's Stadium Bridges are reopening on Wednesday, November 14, 2012 after about a year of being closed for reconstruction, according to messages from the city. The latest information that I have is that the bridge will open at 5:00 p.m. Wednesday, but that there will be intermittent lane closures for the rest of the week to finish up the job. City engineer Mike Nearing emailed me to say that "at least one sidewalk will be open while our contractor works to clean and finish the work on the roadway and bridges."


Photo credit:

Our neighborhood had a block party to celebrate the end of construction last weekend, and was on it. Distinguished visitors included Rep. John Dingell and Mayor John Hieftje, plus a host of neighborhood kids (my boys included) who ran, scootered, and bicycled on the brand new structure.

We'll all be glad that the detours that made our west side neighbors seem like they were far, far away will be gone, and as an added surprise bonus the bridge will be ready for the final football game vs. Iowa.

More reading:

Bridge Inspection Program Reduced Weight Postings for E. Stadium Boulevard over S. State Street File No. 2006-014.17

Thanks to Alan Pagliere for unearthing this memo, entitled "The Bridge Is Falling".  Note the date.  Alan says "read it, appreciate the dates and the content, and when you pick your jaw up off the floor, contact the City of Ann Arbor before driving confidently under or over that bridge."


DATE:    February 26, 2008

TO:        Homayoon Pirooz, P.E.
Manager, Project Management Unit

FROM:    Michael G. Nearing, P.E.
Senior Project Manager, Project Management Unit

RE:        2006-2007 Bridge Inspection Program
Reduced Weight Postings for E. Stadium Boulevard over S. State Street
File No. 2006-014.17 (mgn)

We are writing to inform you of the recent investigation and
analysis that was performed on the E. Stadium Boulevard Bridge over S.
State Street.  We are also reporting on the condition of the bridge and
providing information regarding possible short- and long-term solutions
for the E. Stadium Boulevard Bridge over S. State Street and the E.
Stadium Boulevard Bridge over the Ann Arbor Railroad tracks.

Attached, please find a Traffic Control Order (TCO) that
recommends a reduction in allowable gross vehicle weights for the E.
Stadium Boulevard Bridge over S. State Street in accordance with the
limits contained in this memorandum.


On December 29, 2007, our Field Operations forces were called
out to the E. Stadium Boulevard Bridge over S. State Street as
medium-sized pieces of concrete were falling off of the bottom of one
of the box beams that support the roadway.  These pieces of concrete
were large enough to damage passing vehicles, if they were to strike
them.  Our Field Operations and Safety Services personnel closed one
lane of traffic at a time and removed the remaining loose concrete from
the underside of the box beam.  No injuries due to the falling concrete
were reported.

As a result of the concrete removal, we reviewed the structure
again and were concerned about the condition of one of the box beams. 
In early January 2008, a meeting was held on-site between Project
Management Unit, our bridge inspection consultant, and bridge design
personnel to review the condition of the bridge and (1) determine what
possible courses of action could be taken to help prevent further
damage to the bridge and (2) identify possible repair strategies.

We directed our consultants to re-analyze the bridge structure
given the section loss that had just occurred.  As you may recall,
effective January 1, 2008 we lowered the weight limits due to section
loss that was discovered during the biennial inspection that was
performed in late October 2007.  Based upon the new analysis that was
performed in January 2008, it is recommended that we reduce the weight
limits on this structure again.
Condition of the bridge

The existing bridge is composed of 16 pre-stressed concrete box
beams that are laid side-by-side.  They are “tied” together with steel
post-tensioning rods that connect pairs of beams together.  The beams
are overlaid with an asphalt wearing surface.  There is a concrete
sidewalk that has been cast on top of the two northernmost beams.  The
bridge does not provide sufficient vertical or horizontal clearances
and is considered structurally deficient and functionally obsolete.

One of the box beams has developed a severe longitudinal crack. 
This is the beam that our field personnel had to hand-chip to remove
the spalled concrete in late December 2007.  There are other beams that
are developing longitudinal cracks, as well.  Other beams have several
broken pre-stressing strands and the abutments that support the beams
are in poor condition.  Note that the pre-stressing strands are the
primary elements of the bridge beams that provide structural strength. 
Based on these deficiencies, the bridge, viewed as a whole, is
considered to be in poor condition.  The beam that is severely cracked
is considered to be in serious condition.

Upon review of the “as-built” drawings of the structure, we
believe that it is not possible to repair the severely cracked beam in
any manner that can restore its structural integrity.  This is due to
the location of the beam itself, and the location and configuration of
the post-tensioning rods that tie the box beams together.  The severely
cracked beam is the fifth beam in from the south side of the
structure.  Due to the manner in which the bridge was constructed, it
is not possible to replace only this beam. In order to repair the beam,
we would have to cut the post tensioning rods on each side of the
beam.  We would not be able to access the needed areas of the beams to
re-install the post-tensioning rods, however, effectively leaving the
beams to function individually.  This would be unacceptable.  There is
also one other beam that contains small cracks that currently are not
as severe as the beam described above, but we believe that it is likely
that it, too, will crack in a similar manner.  AS A RESULT, WE BELIEVE

Exacerbating the problem is the condition of the remaining
beams.  We believe that it is likely that the tops of these beams have
begun to spall.  It is apparent to us that salt-laden water has seeped
between the asphalt layer covering the beams and the beams themselves. 
Water routinely leaks around the beams and runs down the abutment
walls.  Over time, this moisture and salt will cause the concrete to
disintegrate.  Given the length of time this has been occurring, we
have reason to believe that it is possible that the tops of the beams
are damaged to the point that they may not be able to be repaired, if
we were to attempt it.

We also believe that any attempt at performing a repair itself
would be expensive.  We do not have detailed costs at this time, but we
estimate that it would cost at least $250,000 to attempt to replace the
five to eight south side bridge beams.  Also, it would take at least
one month to perform the needed construction.

At your request, we could prepare a more thorough and detailed
estimate of the repair costs and other possible options that could be
implemented should funding for the replacement of the structure not be
available in the foreseeable future.  This evaluation would cost
approximately $15,000 to retain the services of a structural engineer
to analyze and review various options.  We also recommend that about
$10,000 be budgeted for our Field Services personnel to assist in the
performance forensic investigations on the bridge in order to better
determine the extent of deterioration of the existing bridge beams and

We do not believe that it is possible to repair the bridge over
S. State Street cost effectively, however.  This is due to the
extensive deterioration of the existing beams, abutments, and
asphalt-wearing surface.  As mentioned previously, the bridge is
considered structurally deficient and functionally obsolete.  These
deficiencies cannot be easily remedied.  We will, of course, continue
to monitor the condition of the bridge. Should it become necessary, we
are prepared to repair the structure in order to allow the bridge to
remain in service.

Proposed Short-term Action

In order to help minimize damage to this structure and prolong
its life span to the greatest extent possible, we are recommending that
the weight limits be lowered.  We have prepared the following table
that compares the existing and proposed weight limits for the three
classes of trucks that can use the structure:

Vehicle        Existing
Posted Load
(since January 1, 2008)    Proposed
Posted Load    Reduction in
Load carrying capacity
Single Unit Truck        31 tons    19 tons    39%
Two-Unit Truck        39 tons    24 tons    39%
Three-Unit Truck        44 tons    26 tons    41%

The proposed Traffic Control Order (TCO) recommends a reduction
in gross vehicle weight for the three types of trucks that can travel
on Michigan roadways without special permits.  They are one, two, and
three-unit trucks.  A single-unit truck is any truck without a
trailer.  A single-unit truck can be any number of common vehicles. 
Some examples of this would be a school or AATA bus, moving van, or in
the worst case, a fully loaded concrete truck.  A two-unit truck can be
most easily described as a semi-truck with one trailer.  Note, a
pick-up truck or car pulling an “ordinary” trailer (such as the
trailers that lawn maintenance companies would use) would not be
considered a two-unit vehicle. Finally, a three-unit truck can be most
easily thought of as a semi-truck pulling two trailers.  An example of
this would be the large sand or gravel hauling trucks that bring
materials to construction sites.

The recommended gross vehicle weight reductions are
significant.  Also, the overall condition of the bridge has declined
measurably over the course of the last calendar year.  We expect that
the condition of the structure will continue to decline as the
structure is nearing the end of its useful life.  Based on the rate of
deterioration that we have observed over the course of the last few
years, we believe that the structure has approximately three to five
years in which it will be able to carry trucks.  We also expect that
additional weight limit restrictions will be necessary in the future.

Proposed Long-term Actions

As you may recall, we have begun a project to perform the
preliminary design of the replacement for this structure, as well as
the E. Stadium Boulevard Bridge over the Ann Arbor Railroad tracks. 
The bridge over the Ann Arbor Railroad tracks is located about 300 feet
to the west of the bridge over S. State Street.  We believe it makes
sense to consider replacing both bridges at the same time, although it
is also possible to replace the two bridge structures at different

We have not able to move forward on the preliminary design of
the bridge over S. State Street or the Ann Arbor Railroad tracks
because we are waiting for the 4th Ward City Council members to
nominate and confirm a Citizens Advisory Committee to assist us with
the public engagement process.  It has been our experience with
projects of this nature that it is important to consider and review all
aspects of the proposed design with the citizens in order to make sure
the project that we deliver meets community expectations.  This process
will also help us to avoid conflicts later in the design process as we
will have already confirmed the design approach and aesthetics of the
project with the public and City Council.  Finally, this preliminary
design process will allow us to better estimate the cost of the project
based on a more complete picture of all project elements.

We have estimated that it will take about 2 to 3 years to
prepare for bridge replacement including the public engagement and
internal project review process; the preliminary and final design of
the bridges and needed approach work; and the development of a funding
plan for the project.  We have prepared a tentative schedule for this
project such that its construction could be started shortly after the
University of Michigan’s Football Stadium Renovations are completed. 
We are also planning and coordinating this project so that it is
compatible with the planned improvements along W. Stadium Boulevard. 
Attached, please find a drawing that we have prepared that locates all
of these planned improvements and their anticipated starting and
completion dates.  Also attached, please find the tentative project
schedule that details the required tasks and estimated durations of the
required activities to complete the project’s design.


Fortunately, the reduction in weights that we are proposing does
not yet affect most of the everyday users of this structure.  However,
we believe that when it is again necessary to reduce the posted weight
limits, both AATA and the Ann Arbor Public Schools will be impacted by
this change.

The proposed change will impact the trucking and construction
operations that use this corridor as they, most probably, will not be
able to route trucks through this portion of the E. Stadium Boulevard
corridor between S. Industrial Highway and S. Main Street.  These types
of trucks will have to find an alternative route around this portion of
E. Stadium Boulevard.

We are also working with the Communications Office to prepare a
press release notifying the appropriate agencies of the proposed change.


HP:MGN:mgn (e stadium weight reduction memo 080225.doc)

“The Bridge at Mackinac”, David Steinman

Aerial view of the roadway deck work
Aerial view of the roadway deck work, 1957.

Photo from Mackinac Bridge Authority. Digital materials in the Upper Peninsula Digitization Center collections are either in the public domain, according to U.S. copyright law, or permission has been obtained from rights owners. The digital version and supplementary materials are available for all educational uses worldwide. For further information contact the Superiorland Library Cooperative staff (

In the land of Hiawatha,
Where the white man gazed with awe
At a paradise divided
By the straits of Mackinac

Men are dredging, drilling, blasting,
Battling tides around the clock,
Through the depths of icy water,
Driving caissons down to rock.

Fleets of freighters bring their cargoes
From the forges and the kilns;
Stones and steel – ten thousand barge-loads –
From the quarries, mines, and mills.

Now the towers, mounting skyward,
Reach the heights of airy space.
Hear the rivet-hammers ringing,
Joining steel in strength and grace.

High above the swirling currents,
Parabolic strands are strung;
From the cables, packed with power,
Wonder-spans of steel are hung.

Generations dreamed the crossing;
Doubters shook their heads in scorn.
Brave men vowed that they would build it –
From their faith a bridge was born.

There it spans the miles of water,
Speeding millions on their way –
Bridge of vision, hope and courage,
Portal to a brighter day.

2100 photos of the construction of the Mackinac Bridge in 1957 are in the collection of the Upper Peninsula Digitization Center.

Dummerston Bridge, near Newfane VT

Get more details from the Vermont Covered Bridges site.

We took this bridge on the way to the wedding from Putney to Newfane. You go on East-West Road over a good-sized hill and at the bottom there’s a river with this lovely covered bridge over it. Make sure you put your lights on when you cross since it can be hard to see oncoming traffic.

There are swimming holes on the river this crosses but we didn’t get to stop in to test the waters.

Newfane itself is small and very lovely, there’s a courthouse on the town green and the Congregational church is right there.

It was hot, hot, hot – 98 degrees in nearby Brattleboro. But not so hot as it would seem in the church since it had thick walls.

Mackinac Bridge border control for emerald ash borers

From the Marquette Mining Journal:

State plans checkpoint at Mackinac Bridge

ST. IGNACE (AP) – With summer tourism season getting under way, government inspectors have set up a checkpoint just north of the Mackinac Bridge in hopes of keeping the emerald ash borer and bovine tuberculosis out of the Upper Peninsula.

Northbound motorists hauling non-coniferous firewood, products made of ash wood, and livestock including cattle, goats and farm-raised deer will be required to stop at the checkpoint. It is located in the state welcome center parking lot northeast of the bridge toll booths, officials said Thursday.

The firewood will be confiscated, in keeping with a state ban on taking it into the Upper Peninsula. Wood products such as lumber will be inspected, and livestock haulers will be required to show bovine TB test records and other documentation about the animals they are transporting.

Ash borers are a huge problem in Ann Arbor, killing lots of city trees – it will be disaster when they hit the UP forests.