
props for possibly my fav comment on AO3 ever

props for possibly my fav comment on AO3 ever
Bridges aren’t supposed to have weight restrictions on them. That is, they don’t come with weight restrictions on them when they’re new. So a bridge with a weight restriction on it is a sign that something has gone wrong and the bridge does not meet current standards.
The maximum weight that a vehicle is allowed to carry on the Interstate System per federal law is 80,000 pounds gross vehicle weight (with a max of 20,000 pounds per axle). That’s 40 tons. That limit applies to every inch of pavement, not just the bridges. Since this is a known cap, a new Interstate bridge will be designed to accommodate an 80,000 lb GVW load on it. You could say the bridge’s weight limit is 80,000 lb/40 tons but that doesn’t really have much meaning, because a load higher than that would be illegal to transport on public roads anyway, and the road leading up to the bridge has the same weight restriction. (In practice, the bridge doubtlessly will be designed to have a little bit of let to it just in case some idiot tries to squeak by a few hundred extra pounds.)
Now, note that that law applies to the Interstate System only, because the federal government only has a governing interest in the Interstate System (and other roads that together make up something called the National Highway System) because they partially fund it. Most long-distance roads are owned and funded by the states. The states could theoretically set lower standard weight limits and/or design bridges with lower weight limits…but in practice they don’t.
One, because all of that 80,000 lb GVW traffic on the Interstate system has to go somewhere when it exits the system.
Two, because a group called the American Association of State Highway and Transportation Officials (AASHTO, who are best known for picking the road numbers) maintains a catalog of standard components for making bridges that meet Interstate System requirements. Engineers are expensive on a per-hour basis, so if you can direct your engineer to use standard components and make a standard bridge, that’s a lot cheaper than having them design a bridge from scratch to go over the creek in Nowheresville. As a result, most new bridges meet Interstate standards and have an 80,000 lb GVW rating even if they aren’t on the Interstate system. (This is also why all new bridges kind of look the same, but we’re not worried about how boring the bridges are for the sake of this post.)
So a bridge only has an explicit weight limit if it has been damaged in some way (through failure to properly maintain it usually) or because it predates the application of Interstate System standards and the standard AASHTO bridges.
Older bridges often have other problems in addition to the weight limits: many older designs are what we call “fracture critical”, which means that if one component of the bridge fails the whole thing collapses. Modern bridge designs have redundancy designed into them so that if one beam fails the other beams will carry the load until the damaged beam can be replaced. Older bridges also often don’t meet other standards, like height (16 ft clearance) and width (12 ft per lane plus 14 ft for shoulders) requirements.
Biden isn’t advocating eliminating weight limits and letting it be a laissez-faire free-for-all where trucks can just go wherever they want. He’s advocating for replacing bridges that carry weight limits with new ones that don’t have them.
wow i got absolutely schooled thank you for all this this is really informative. i have learned so much
This is a great explanation of what the fuck Biden was talking about in his tweet. because I will freely admit that I also went “…….wtf?????” when I read it. So thank you.
Today I learned about civil engineering.
shoutout to all the aces that used to think they were bisexuals/pansexuals. i was there too
ID: a digital comic that consists of three panels, featuring an anthropomorphic cat. In the first panel, the cat is doing some math in their mind, their thought bubble reads "Attraction to boys = 0; attraction to girls = 0; 0 = 0". In the second panel, the cat smiles at the camera while raising their index finger, saying "I'm bisexual!" with a bisexual pride flag below. The third panel has the cat turning around and moving their fists thriumphantly, shouting "Yes! I figured it out!"; on their back, an asexual pride flag is stuck with tape, but they don't realize. Yet. End ID.
My dad was in Canmore last week and visited the Burgess Shale. He found this fossil there (didn’t take it obviously just took a picture of it) and I’m hoping someone on Tumblr might be able to help us ID it. He’s thinking it might be a juvenile anomalocaris (I have doubts but I don’t know enough to say for sure).
I’m sorry but no modern comedy will ever top this
Watching them start losing it is half the joy.

went to see if my late package maybe showed up without being scanned

but the post man yesterday said it would be here at ooooooooooone

is 9…………. post office closing time……. no pkg……………………………………………………… >:C

well at least i can skip my post office visit tomorrow

i mean what did i expect really
a package?
too unrealistic

amazon sent me a replacement for my lost package and it “arrived” today


omg she recognized me immediately and got nervous with me while checking the system using my name
she was just as distraught as me when it turned up “arriving tomorrow” again but then she had another idea
mail is dumb
The mail lady saying “NO. I REFUSE to say it again” was more climactic than the Braveheart speech.
oh my gosh, op’s bio says “The package was a laptop” which gives SUCH a new perspective
Imagine an alien sharing a cool human fact they just learned like ”hey guys did you know that the silvery markings on humans actually aren’t true stripes? They’re called stretch marks, they happen when the human is growing fast enough to actually outgrow their skin, which is apparently something that just fucking happens to almost all of them at some point of their life.”
and another one is like ”wait so you’re saying humans don’t have stripes.”
”actually they do, but the stripes are invisible. There’s genetic code that’d give them stripes but they’re just the same colour as the rest of the skin. So the visible stripes are not real stripes and the real stripes are invisible.”
”I swear if you tell me one more weird human thing today I’m beating your ass.”
The human in the room looks up and goes "Wait I have stripes?"
"what do you mean cats can see them, but I can't?"
what do you fucking mean cats can see them
NO NO ITS NOT "IT THINKS I HAVE THEM"
BECAUSE WE DO APPARENTLY
SO ITS ACTUALLY A VERY DISTRESSED "MY CAT THINKS I KNOW I HAVE STRIPES?!?!?!"
AND I THINK THATS A BIT WORSE TO BE COMPLETELY HONEST
@beenovel @messiambrandybuck these are the variants
WHAT
I NEED TO KNOW WHAT PATTERN OF STRIPES I HAVE AND THE CATS WON'T TELL ME
They’re called Blaschko's lines!!!
The reverse can also be true ... kinda.
I remember reading somehwre the human eye can see more shades of green than any other colour. I just googled it and the human eye can see 10 Million different shades of green.
So human could see stripes and patterns on, say, a reptillian race who maybe can’t see as many colours as we do, and think they’re just one boring shade of green.
Human: We have stripes?! I wish I could see them. I hope they look like yours.
Reptile Alien: Wait, I HAVE STRIPES!
*mutual excitement all around*