Ambassador Bridge in just "fair condition" - secret report says

The Ambassador Bridge company fought so fiercely the release of an annual engineer's inspection report it was bound to get huge media attention when it was released today by veteran Michigan congressman John Dingell. Two courts had rejected the bridge company's efforts to invoke national security and proprietary data to keep under wraps the report by wellknown bridge engineers Modjeski & Masters.

We've got a 12 pages  "Summary and Conclusions" of the report from Dingell's office. As a bridge company spokesman Phil Frame said beforehand the report doesn't reveal any "smoking gun" or single threatening condition.

But it certainly paints a picture of an old bridge, that needs a lot of work done on it if it is to be kept in use longterm.

Overall fair, not poor, but not good

M&M describe the bridge as "in overall fair condition."

That's a notch up on poor condition but a notch below good condition and two notches below excellent condition.

Deficiencies in the main cables are listed that require "priority attention." These involve cracked paint and missing caulk that allow moisture to penetrate and rust the steel. So far however the interior condition of the main cables was found to be "generally very good."

The main cables are the primary structural element of any suspension bridge.

About a third of suspender ropes had to be replaced in work that occurred at the time of the report and a number contain broken ropes.

Anchorages are described as in good condition despite cracks, spalls, exposed rebar and efflorescence "throughout the anchorages."

Substructure shows signs of aging.

The suspended structural steel of the mainspan "ranges from fair to good," the report says. Many repairs have been done recently but "many deficiencies remain." Stringers are separated from deck floorbeams and there is some severe corrosion and cracking.

Bearings in the truss and girder spans are generally satisfactory although a few are in bad shape.

The towers are in good condition though some of their ladders are not.

The mainspan deck is described as "in poor condition" with cracked, unsound and spalled concrete, exposed and significantly corroded rebar on top and bottom surfaces. Pressure relief joints aren't working, concrete is separating from the underside of the deck in places and some joint components are missing.

Approach decks are in poor to fair condition. The Canadian side is in worse condition - due to worse weather over there perhaps?

Railings are in "poor condition."

Some are so deteriorated they have "reduced capacity to  resist vehicular impact."

Railings are already scheduled for replacement, the engineers report.

Lighting and electrical systems are in "fair to poor condition." There are exposed wires and missing covers on junction boxes. Some lighting doesn't work.

Maintenance/inspection travelers are described as having operational and safety problems.

Reaction

In response to release of the report today bridge officials stressed that the report is from 2007 and they said some of the deficiencies have since been corrected. They said a complete redecking of the mainspan will begin next spring.

A 2008 report also calls the bridge "in overall fair condition," the same term used in the 2007 report.

COMMENT: Poor maintenance of the 1929 span is hardly surprising given that the bridge owners have been adamant they want to build a new span to replace it, and have started work on the approach on the American side. It would be a waste to pour a lot of money into a structure you expect to take out of service in a few years time.

Trouble is there is strong opposition to the new span which at six lanes would handle larger volumes of traffic than the existing 4-lane bridge. Authorities on the Canadian side where the bridge dumps traffic into a signalized mainstreet of Windsor - Huron Church Road - say they won't allow the new bridge to be built.

The Canadians want a new bridge to be built a couple of miles downriver. Parkway style and depressed expressway standard approaches to the downriver bridge are already permitted there and the land is acquired.

Trouble is it is quite unclear whether the downriver bridge is financially viable. On the US side opinion is strongly split between support for a replacement span for the Ambassador and the downriver bridge.

A traffic and revenue study is being done by Michigan DOT to prepare the way for a possible toll concession to raise private funds to build the downriver bridge - if the numbers pencil out. That is far from clear since Michigan is an economic disaster area.

Here is the M&M summary and conclusions we worked from:

http://www.tollroadsnews.com/sites/default/files/Sum&Concls5.pdf

TOLLROADSnews 2009-10-15