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RE: Longevity of freeways, our 110 freeway is 70 years old... perhaps the misalignment of expansion joints is just from the constant pounding of millions of cars running down the road?
Jim also has a good point, our freeways were designed with 50's-60's automobiles in mind |
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Then it started getting a little rough over the years until it got pretty bad. In the 90's they cut grooves in the concrete squares at the joints and installed metal connectors and epoxied them in and ground the surface to make it smooth and stay that way. Then they ground the surface smooth again a few years ago. |
Remember when the speed limits were changed to 55 and there were concerns that the distance between the expansion joints were tuned to the trucks going 70 and were tearing up the hwy's.
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. Since many states are near broke, the states often can't come up with the state share of the match, ie, Feds kick in 80%, States and locals kick in the other 20%. The sad thing is sometimes projects don't get let to bid because the States can't cover their 20% share and the Fed dollars can get re-allocated elsewhere. This is especially true in states with big, fat social programs and hungry mouths. The road money goes to feed the poor because highways don't protest to the politicians. So some big highway maintenance jobs don't get done timely and then those needs just get worse, and the pavements completely fail. And on and on. |
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See the photos I posted. In the first photo, see those damn ridges behind the little silver car? Those damn thing is what I am talking about. It even more prominent in the second pic. Its all over the entire fwy. All those sections are new. This isn't settling over 5-10 year beating to hell by big trucks, its new?
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Thankfully, I don't have to drive that big old truck often. Once a month to keep things running. loaded up isn't hat bad. That's my Alaska road trip truck. My poor wife will be in it for more then a month:D She's gonna to be pissed:cool: |
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She tells me that she has been on enough road trips with me to last three more marriages
We started it back in college. Poor girl |
She must be a saint. :)
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A lot of the expansion joints are because they didn't have the technology to lay long, continuous stretches of concrete at the time.
Oldest freeway I know of is the Pasadena freeway out of down town LA. My dad said he used to drive on it when he was out here in '48 in a Model A Ford. |
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There are date stamps along the fwy if you look closely. It was known as the Arroyo Parkway. They even changed the name on some of the signs confusing some people. Remember our fwys had names not just numbers and everyone used them? When I was a little boy, older folks would say, take the Harbor fwy to San Pedro or the Hollywood Fwy, Pasadena, Santa Ana and the San Diego fwy. We were at someplace about 3 months ago and I saw an old bumper sticker that said "The Santa Ana Fwy sucks" Bet that was printed before they widened it. I still say those names to my wife and she would correct me with the numbers and tells me no one will understand me. :D |
We used to go to my aunt and uncle's place when they lived in Eagle Rock. We drove on the Pasadena fwy, before they paved it with asphalt. It had some great expansion joints as the concrete seemed like it was poured in 20-30 foot long sections. The on ramps really allow you to test the 0-60 time of your car as they are shorter than short. You can really tell it was designed with Model A's in mind.
Before the 405 was built, we'd go to my aunt and uncle's down in Torrance via Sepulveda Blvd. Hawthorne Blvd had strawberry fields on either side of it thru Torrance. |
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Your pictures looks like an old highway when they cut the slots at 90 degrees. |
I remember watching them widen and expand the short stretch of road from 526 to the port in Mount Pleasant.
The concrete had to be at least 16” deep and had massive amounts of rebar in it. Probably #8. When I built my first house, it was on a hill. We poured the driveway with wood expansion joints. The concrete slumped just a little at every expansion joint and drove me nuts driving on them. Bump! Bump! Bump! |
Here is a link of many found on the subject....
https://www.fhwa.dot.gov/pavement/t504030.cfm Nov 30, 1990 - TRANSVERSE CONTRACTION JOINTS. The primary purpose of transverse contraction joints is to control the cracking that results from the tensile and bending stresses in concrete slabs caused by the cement hydration process, traffic loadings, and the environment. |
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They are there on purpose. The idea is that with the grooves it takes longer for the concrete to "polish" to the point where it becomes to slick in the rain. They aren't trying to drain the water, just to provide longer lasting texture on the surface. FYI - they don't care about the ride for our sportscars or stiff trucks. |
Okay - I think I see what you are taking about. There are groves running in the direction of travel that are about 1-2 inches apart. In the case of that road there could be two goals: improve wet traction and/or reduce noise. We have similar groves in Hwy 85 here. In our case the original idea was to reduce noise by grinding the surface to a pre-determined smoothness, I think the groves were added to improve wet traction (because of the smooth surface) and also improve noise generation or at least not increase the noise generation. Hwy 85 is a good place to test if your tires are out of balance, the road is as smooth as I've experienced.
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So here is the theory -
Traction on concrete is mostly controlled by "micro-scale" roughness. The problem is that at this micro-scale the concrete pretty rapidly gets polished by the action of tires, then acts like a terazzo floor. By cutting those grooves the wear of the concrete is continually exposing rough concrete going down the sides of each groove. The large grooves aren't only annoying with sportscars, motorcycles and some tread designs - they reduce the traction surface under your tire contact patch. The highway engineers have decided that the longer maintenance interval is worth it. They used to use a rough "broom" finish or similar - but that ends up polished more quickly. When the travel lane is so smooth the Joe Public is hitting the guardrail in every rainstorm, the highway department needs to do work. So the grooved surface wears a bit faster in terms of inches per year, but it maintains traction longer. |
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