Q: I am sure you have addressed this before, but I never saw an answer. We have always been told that the grates on the Hokendauqua-North Catasauqua Bridge were installed upside-down. I sometimes think this is an urban legend. How about it?
— Jim Miller, Whitehall Township
A: I have heard of this tale, Jim — somewhere, at some time. I can't remember if it was an email query like yours, or something related in a phone call, or what. I haven't previously mapped a route to the answer.
I think you're right: It's a safe bet that this is, indeed, an urban legend — or in this case, a tall suburban tale.
Spanning the Lehigh River, this county bridge was built in 1908, according to PennDOT. Other references put the date as early as 1893. Suffice to say the structure is so old; nobody knows for sure how old it is.
The bridge clearly was refurbished in 1947 — a plaque attests to this — and Mike Bednar of Hokendauqua, who lives near the bridge, said the steel grates replaced a wood surface at that time. Bednar, 64, said his late father clearly recalled the grating replacing a wood-plank surface.
One other certainty: It's a rickety old bridge at this point, with a three-ton weight limit, and the supports for the sidewalk attached to the north side are so weak that the walk is closed and pedestrians forbidden.
So it's no big surprise that the bridge is scheduled for $13.5 million worth of demolition and replacement, with work to begin in December, shutting down traffic in both directions for two years.
After more than a century of service, "I'd say we got our money's worth out of it," said Lehigh County General Services Director Glenn Solt.
With the wrecking ball coming down the road, we better gear up to answer the pressing question of the upside-down grates before it's too late. It's not clear how the rumor got started, or when, but many people say they've heard the allegation for many years.
PennDOT spokesman Ron Young said he's been asked about the upside-down grates "fairly frequently," mostly by people who say they'd heard it from " 'old timers' who were there when the grates were installed." However, officials including former PennDOT engineers Gerry Fry and Don Lerch (both of whom have since moved on to jobs with private firms) have told Young it's not true.
PennDOT engineer Dennis Toomey hadn't heard it before, and said he considers it "far-fetched."
Solt has heard the rumor "many times" over the years.
"I've always heard that, and I can tell you it's not true," he said. The tale has even come up informally at meetings, and engineers always agree the grates could not have been installed upside-down, Solt said.
He tried to help me understand how an engineer, contractor, or experienced construction worker could tell the grates are right-side-up. A regular warrior might be able to figure it out, too, and I'm proof of that, because I got the basic concept — later confirmed by Solt — during my site visit.
I hope today's photograph helps explain the principle, though without seeing the grates in person, it could be a rough road. Basically, the diamond-shaped grates are riveted to the horizontal steel strips, and the strips rest on vertical I-beams. The grates are riveted to the top edge of the strips, such that they're positioned "up," as much as an inch above the I-beam surface that the strips rest upon.
If you were to flip the grate-and-strip assembly completely, turning it upside-down to replicate the rumored blunder, the bare steel ribs would be sticking up, an inch above the grating, such that the road surface would consist of the top edge of the all the steel strips, running in the direction of traffic. The strips would be spaced about two inches apart; there'd be virtually no traction.
It simply could not have been done that way, Solt said. An anonymous post on a blog site suggested construction workers must have enjoyed a liquid lunch at a nearby watering hole, but even a whole crew of drunks could not have perpetrated this blunder; the design of the bridge components renders it physically impossible.
The matter of what might have prompted this urban legend presents an interesting turn in the road, Jim. Nobody I asked, even those familiar with the rumor, could say, but one theory came to me as soon as I drove onto the bridge while investigating the question.
Some steel-grate bridges can produce an unsteady ride for motor vehicles, seeming to "push" the car a bit from side to side. This effect is extremely pronounced on the Hockey-North Catty bridge, or at least, it seems that way to me. I drove across it several times to make sure I wasn't imagining things, and the grates really seem to "throw the car around."
My car is less than a year and barely 8,000 miles old, with no worn tires or suspension problems or anything of that nature. It's one of the smallest cars on the market, but it's normally very stable with good handling.
I surmise that motorists started talking about this effect at some point — here's where a watering hole could have factored in — and speculation on the cause slowly progressed to upside-down proportions. A fanciful suggestion morphs into "such-and-such said," which becomes "they say," which ends up as "they installed the grates upside-down!" Isn't that the way this stuff develops?
As it turned out, my idea wasn't new. I came across this anonymous website post from 2008: "Rumor always had it that when that bridge was built, the workers put the metal grates in upside-down. That's why your car always shimmies back and forth while you drove across. I don't know how true that story is (I've heard it several times), but I definitely don't doubt it."
He definitely should have.
We may never know what prompted this piece of folklore, Jim. But our vital search for truth has proved to be a fun ride.
Road Warrior appears Mondays and Fridays, and the Warrior blogs at mcall.com. Email questions about roadways, traffic and transportation, with your name and the municipality where you live, to firstname.lastname@example.org, or write to Road Warrior, Box 1260, Allentown, PA 18105-1260.