Back when the New York Central Railroad built the overpass at North Clinton Avenue, likely around the late 1800s, they had no idea the I-beams under the tracks would eventually look like this:
The longitudinal I beams have more iron and haven’t corroded through:
But the footing under that beam doesn’t look very good at all:
I think that Lego brick is a nice touch …
We drove the van along I-90 to Rochester and passed many bridge repair operations. The NY Thruway isn’t all that old and the rebar has been corroding out of the concrete pylons for years.
Nowadays, we use exactly enough material to carry the anticipated loads and not one gram more; fast forward a century and our structures won’t be around.
Those pictures were taken from the platform just west of the covered section.
The Smell of Molten Projects in the Morning 
Comments
7 responses to “Rochester NY Railroad Station: The Merits of Overbuilding”
And they can’t use red lead paint anymore. Probably the reason the old structures lasted as long as they did.
The house came with a gallon can of genuine red lead primer that I handed in at a hazmat collection day: they don’t make paint like they used to and that’s a good thing!
I got a look at some of the bridges, both under repair and awaiting (I hope!) as I was driving along I-94 in southern Michigan. Lots-o-rust… I think that I-beams fell out of favor 40+ years ago and were replaced by wide-flange beams, which have more steel in the flange section. Still, with harsh weather, they go away.
OTOH, my neighbor is working on his barbed wire fence. I know the guy who put it in the first time, in 1945(!). Much of the wire has been replaced, but the original bits are still intact, if brittle. I doubt the 1945 stuff was galvanized. One advantage of living in a semi-arid climate.
I wonder what construction fault lets (salty) water inside the concrete column, where it corrodes the rebar, which expands and spalls chunks off the surface. It’s obvious on pretty nearly every Interstate overpass between Albany and Rochester, with repaired patches just making the damaged areas even more conspicuous.
Porous concrete? Cracks while curing? Poor rebar installation?
I’ll have to ask my friend. He built the fence, but is also a retired concrete engineer; worked for California DOT and consulted on some huge projects (three rivers dam in China, for one).
Taking a SWAG, the concrete should be porous to an extent–that’s partly how it deals with water. I’ve noticed that the current practice for bridge rebar is to use an epoxy coating. It’s not perfect (said friend witnessed somebody welding, using the coated rebar as a ground return, so the pinholes must be fearsome), but it’s going to be better than nothing.
Poor installation would consist of getting the bar too close to the surface. Possible, and maybe likely if the work is sloppy. Rebar was frequently the mystery meat of steel, too, so poor alloy usage would be an issue, too.
In Michigan, the spooky part was seeing the rust on the bottom flange of the beams. Judging by the rusted fenders, I suspect the state uses a whole lot of salt.
Could be the dreaded Alkali-Silica Reaction ( http://en.wikipedia.org/wiki/Alkali%E2%80%93silica_reaction ) which is disolving the Raleigh beltline and forcing the removal and rebuilding on the southern half of the beltway. Yeah, traffic stinks.
Wow, that’s nasty!
We lived north of Raleigh in the mid-90s, when they were hammering the north part of the Beltway through the woods. I vaguely recall a story about one of the high entrance ramps, where they used the wrong kind of gravel fill, and had to re-do the whole thing.
The bridge columns I’ve seen around here don’t show that alligator-skin pattern, but I admit to passing at a pretty good clip. Some have exposed & corroded rebar maybe an inch under the (missing) surface, surrounded by a spalled crater, which seems like something wrong with the rebar.