View this page "Raining Bricks"

[Rex]

Before, I begin to expose this process to the entire APA UD Committee
I would appreciate feedback.

Talk about Infrastructure (on page link below) is like that old joke
about the cousin that thinks he's a chicken. When asked if you are
getting him help, the answer is No. Why not? Well, we need the
eggs. Feel free to invite all of your friends and cousins to
participate. Point them to "looking for ideas", lots of issues to
choose.

Click on http://groups.google.com/group/urban-design-committee/web/raining-bricks
- or copy & paste it into your browser's address bar if that doesn't
work.

Thank you for your indulgence.

Rex

[holly@city college]

This is a good list of infrastructure failures. I happen to find
infrastructure very sexy, but that's because in my house growing up we
talked structural steel and re-enforced concrete at the dinner table.
In political circles, there's no photo ops and ribbon cutting headline
news in painting, welding, or engineer's drawings, so fewer and fewer
funds find themselves in our maintenance budget, but there are other,
more intractable, communication bumps in the road to effective and
safe infrastructure standards and maintanance.
Re: the I-35 Minneapolis Bridge collapse. I have a little story to
relate.
My Dad is a retired NYSDOT Civil engineer, whose specialty was and is
bridges. He lives in the UP in Michigan now, and when that bridge
came down he was furious, because he knew it was a design flaw.
He told me that years ago he was sent out to check out a call from
troopers that a large stone had been thrown to the ground on the
Interboro Pkway.
>From the site of the missing stone, there was no discernible reason
for this to have happened. It was a torsional force that spewed that
stone from its place and it shouldn't have happened.
Following the stresses far upstream however, he found that the 4"
expansion joints in the overpass had completely filled with sand and
caused the deck to torque, causing the stone to be thrown.
As a result of that inspection and my father's report, NYState design
standards call for 25' expansion joints!! 25feet! My father contends
that the Egyptians building pyramids knew about this and designed for
it.
My Dad accessed Minnesota DOT inspection records and looked at the
inspection reports. Similar 'incidents' had been reported and
inspected, yet no cause was found and no significant actions were
taken.
My Dad got in the car and drove 400 miles to the bridge, where a
police officer stopped him from entering the site and photocopied his
drivers license.
He stayed over night in a motel and the next day returned to the site,
when he was surrounded by police cars, removed from his car and
arrested. After an hour or so harangue and interrogation, my father
was told to leave the state and not return. He thinks that the cops
wanted to get their hands on an engineer after fishhing bodies out of
the Mississippi River, but I am thinking cover up, as the story seems
to have mostly disappeared (he called the NY Times and they said they
had taken their reporter off the story).
My father's concern is that when checking Minnesota design standards,
he found that their expansion joints were the mere 4" in length. He
wonders how many other states have this error in their standards, and
he is trying to get the word out. I am pasting his 2 page report, at
the end of which my father cites his agenda, which is as a public
servant, a post I find rarely filled these days, although I thankfully
work with many who are truly public servants:
I 35W over Mississippi River Bridge #9340
> > > August 15, 2007
> > > Bill Kallman, PE
> > >
> > > Investigation of Collapse by Kallman Engineering
> > > On August 1, 2007 at 6:05 pm the subject bridge completely collapsed, from
> > > abutment to abutment. The bridge consists of approach spans consisting of
> > > stringers, and a 3-span deck truss over the river. Completed in 1967, this
> > > bridge has had major repairs since then, and in-depth inspections since 1997.
> > > Two engineering reports, one by University of Minnesota Civil Engineering
> > > Department in 2001, and the other by the URS Corporation in 2006 attempted to
> > > explain faults discovered in the field inspections made by Mn-Dot for over 30
> > > years. The complete file is found on the Mn-Dot website
> > > http://www.dot.state.mn.us/i35wbridge/history.html and we have read all of this
> > > material and visited the actual bridge site in Minneapolis.
> > >
> > > We conclude that the approach pavements on-grade shoved the bridge during the
> > > replacement of the transverse joints on the trussed section, hard enough to
> > > destabilize the upper chord members, detach the deck, and drop the center span
> > > at the points of contraflexure. Less than a second later all the other spans
> > > fell towards the river.
> > > The very warm weather preceding August 1, 2007 and the deck joint removal
> > > defined the timing of the collapse. The “frozen†bearings, cracked and
> > > misaligned approach span members, early deck repairs, the tilted north pier,
> > > distressed condition of the on-grade highway pavement joints leading to the
> > > bridge, all point to severe pavement shove as the cause of collapse.
> > >
> > > Quite often, and erroneously so, the phenomena of joint widening in P.C.
> > > concrete pavement is associated with traffic loads, age, and water infiltration.
> > > NOT SO. As the concrete slabs expand and contract with temperature change,
> > > sub-grade material forced up into the joints ejects the joint filler and
> > > gradually widens the joint. This causes a general movement of the pavement
> > > slabs (downhill usually), often relieving the pressure by “blowing up†at a
> > > joint during hot weather. An asphalt repair is then made by a highway
> > > maintenance crew to be permanently replaced by concrete at a later date, which
> > > in turn increases the shove forces.
> > > Any bridge in the way of this pressure will have its bearings displaced. Later
> > > the abutment backwalls are sheared off at the bridge seats, decks rotated, and other signs of distress appear.
> > >
> > > During my 35-year career with the New York State DOT, a pavement detail was implemented prior to the 1964 Worlds Fair in Queens, NY, where a 5-foot expansion joint was introduced into the at-grade concrete pavement. This joint was ordinarily asphalt on the sub-grade and served well, but required removal the resultant “bump†, annually. I recall later lengthening it to 25 feet for ease of construction and maintenance. These joints were called Stress Relief Joints. I know of no experimental work on this phenomena, however measurements of compression within pavement slabs have approached 8,000 p.s.i.. I believe this pavement shove affects many, if not most, bridges and should be eliminated by appropriate details in highway pavement design.
> > >
> > > With great respect for the responsibility to our clients – the highway travelers who in this case have been killed by our ignorance, I consider it our duty to inform the public of the cause of the collapse, our regret for the lives lost,
and our program to see that this doesn’t happen again.
> > >
> > > Bill Kallman
> > > Structural Engineer
> > > 310 Mesnard Street
> > > Hancock, MI 49930
> > > Phone: (906) 482-5202
> > > Fax: (906) 482-5202 (call first)
> > > E-mail: billk...@charter.net
> > > CT 16546 MI 41074 NY 40760