Fine for creating a wake: $27,500
 

Greg,
BTW - Is it cheaper per trip if you get one of those bar code stickers
to allow you to pass through without having to throw coins in the basket, if
so, do you know by how much? Just curious.

I don't have a clue. When I lived there in the early 80s a ticket book worked
out to 50 cents a trip. I think it is around the same price per trip, plus a
hundred bucks or so for the sticker. They try to keep the riff raff out.

Fine for creating a wake: $27,500
 

Very well put. Look at rusting cast iron pipes. There are big sheets of
rust. Figure how much air is between those sheets. Same reason rebar
expands if the rust can not flake away.
Bill

"DSK" wrote in message
...
Paul Schilter wrote:

Bill,
When rebar rust it expands?

Yes, it sure does.

Anything I've seen rusted was diminished in
size, eventually to nothing.

Well, if the rust flakes away, then sure it does. However, if the rust is
encapsulated along with the original material, the the whole thing
expands.


I thought if the rebar was encapsulated in
cement it wouldn't rust due to lack of oxygen.

That's the idea, yes. But it doesn't always work perfectly.

I thought the purpose of
rebar was to strengthen the concrete and keep it from cracking.

The purpose of the rebar is to give the concrete some strength in tension.
Concrete is enormously strong in compression, but has almost zero tensile
or
torsional strength.

The concrete can still crack from a number of causes... impact, water
penetration (especially during freeze-thaw cycles), etc etc.

Hope this helps

Doug King

Fine for creating a wake: $27,500
 

"Greg" wrote in message
...
Greg,
BTW - Is it cheaper per trip if you get one of those bar code
stickers
to allow you to pass through without having to throw coins in the basket,
if
so, do you know by how much? Just curious.

I don't have a clue. When I lived there in the early 80s a ticket book
worked
out to 50 cents a trip. I think it is around the same price per trip, plus
a
hundred bucks or so for the sticker. They try to keep the riff raff out.

When I used to use the ticket book, working and going to SFSU was cheaper by
about 10%. Now is just more convenient. Up to 3 transponders there is no
deposit for the transponder. You just give them a credit card number and
they charge the card $30. When the amount is reduced to some lesser amount
($10 I think) they charge the card again. For a check, I think you get a
bill. You get FastTrac only lanes and also the FastTrac is good in any
lane. Takes only a short time towing to use up that $20-30. Is $2 for a
car and $6.25 for 4 axles. Tandem axle boat trailer gets the $6.25 kiss.
The pass is good on all the bay area bridges except the Golden Gate. And we
have about 8 toll bridges.

Fine for creating a wake: $27,500
 

Same reason rebar
expands if the rust can not flake away.

All of those oxygen atoms gotta go somewhere.

Fine for creating a wake: $27,500
 

DSK wrote in message ...
Paul Schilter wrote:

Bill,
When rebar rust it expands?

Yes, it sure does.

Anything I've seen rusted was diminished in
size, eventually to nothing.

Well, if the rust flakes away, then sure it does. However, if the rust is
encapsulated along with the original material, the the whole thing expands.


I thought if the rebar was encapsulated in
cement it wouldn't rust due to lack of oxygen.

That's the idea, yes. But it doesn't always work perfectly.

It doesn't work perfectly, because CONCRETE (NOT cement) is porous.

I thought the purpose of
rebar was to strengthen the concrete and keep it from cracking.

The purpose of the rebar is to give the concrete some strength in tension.
Concrete is enormously strong in compression, but has almost zero tensile or
torsional strength.

The above is true, to an extent. There are a number of things rebar
does in concrete, ONE of which is provide tensile strength. Another
important design consideration is temperature-shrinkage control.

The concrete can still crack from a number of causes... impact, water
penetration (especially during freeze-thaw cycles), etc etc.

Concrete will develop stress cracks just from the loss of water when
curing. Slab cracking, for one thing, is VERY hard to control.

Fine for creating a wake: $27,500
 

"Paul Schilter" paulschilter@comcast,dot,net wrote in message ...
bass,
Forgive me, but I have a hard time with your statement, not withstanding
a wave caused by an underwater earthquake, which I think sets up a wave that
goes quite below the surface, I don't understand what the difference is
between a wind generated wave and a boat generated wave. Depending on the
wind and fetch or the size and speed of the boat one could be equal to the
other. In short I think they should build the construction strong enough to
last normal conditions that the bridge sees and perhaps even hurricane
conditions for these occur as well.
Paul

Paul, it all has to do with frequency, and dynamics. Wind swept waves,
in a protected area like under a bridge, are minimal. The waves from
wind will most likely be coming from somewhere beyond the bridge,
especially if they are perpendicular to the abutements. So, these
waves will be well below there initial strength when they get to the
abutement. When a boat plows through making a huge wake, five feet
from the abutement, that huge wave is almost at it's original
strength, which is likely many times greater than the wind generated
wave.

Fine for creating a wake: $27,500
 

"Paul Schilter" paulschilter@comcast,dot,net wrote in message ...
bass,
I don't claim to know bridge construction, but wouldn't it be founded on
bed rock, or at least huge caissons?

Nope, not at all, Paul. Restrained soils in that area are safely able
to handle somewhere in the vicinity of of 3,500 pound per square inch
pressure. Also, being mostly sand, they are not subject to
expansion/contraction. All this to say that, no, there is no reason to
found on bedrock, or caissons. Even if the soils were crappy, and it
were founded on caissons, likely the caissons in that area would not
be founded on bedrock. They would use skin friction to support the
design loads.

Fine for creating a wake: $27,500
 

"Calif Bill" wrote in message thlink.net...
"basskisser" wrote in message
om...
"Calif Bill" wrote in message
news:wEOyb.23809
Damn! It is a concrete bridge. Shame on the locals and the state for
letting it get in such deplorable condition that the wake from a 21'
boat
would cause it to come down.

Who said that a wake from a 21' boat was going to "make it come down"?
From that statement, I take it you don't understand a thing about
concrete (HOW much does it weigh?) or you'd certainly know that it is
a HUGE problem. Not on just this bridge, but all over. They just
completed a few billion dollar rehab on the bridge over Lake
Ponchetrain in La. because the piers were eroding, and not just in the
ship channel, just the wave action will do it over time.

From 99% of your posts, you prove you do not know ****! Sure, wear and tear
from the water eroding the concrete causes problems. Even bigger problem
you do not seem to understand is the rebar rusts and expands and breaks the
concrete. Normal wear and tear.

Haaahaaa!! I know more about concrete than you will EVER know!! My
thesis was on composite reinforcing in concrete!!! Now, your idiotic
"rust" issue. That is NOT an inherant problem if constructed properly.
EVENTUALLY, yes, the rebar will rust. BUT, if constructed following
normal guidelines, and following ACI 318, which CLEARLY details
minimum coverage for a given situation, and is backed by years and
years of research, you will find that it is not an issue.

But the USCG and the locals going for a
$27,000 fine for causing a wake? IT IS THE BRIDGE OWNERS RESPONSIBILITY TO
MAINTAIN THE BRIDGE! They have used the revenues from the bridge for non
bridge items. No reserve to fix the bridge. Bridge is unsafe for boats.
Boaters should sue the local bridge district. If a boater gets a $27,000
fine, would be cheaper to sue the bridge owners than paying the fine. Just
like the San Francisco Bay Bridge. Toll $2. maintenance costs for bridge
less than 25 cents per car. Local politicians want an election to raise the
toll some more for mass transit, etc. Screw the minority who has to travel
over the bridge. They get outvoted.

I could care less about the politics. As for the technical aspect, YOU
are the one who doesn't know ****.

Fine for creating a wake: $27,500
 

You still know less than ****. Well, you do know ****! Rust and expansion
is a major item for rebar in concrete bridge construction. Actually I know
a lot about rebar. My buddy, who we debate some construction issues, is the
son of the owner of the last american owned rebar manufacturer, and still
sells rebar, now that the foundry's have been sold.
Bill

"basskisser" wrote in message
om...
"Calif Bill" wrote in message
thlink.net...
"basskisser" wrote in message
om...
"Calif Bill" wrote in message
news:wEOyb.23809
Damn! It is a concrete bridge. Shame on the locals and the state
for
letting it get in such deplorable condition that the wake from a 21'
boat
would cause it to come down.

Who said that a wake from a 21' boat was going to "make it come down"?
From that statement, I take it you don't understand a thing about
concrete (HOW much does it weigh?) or you'd certainly know that it is
a HUGE problem. Not on just this bridge, but all over. They just
completed a few billion dollar rehab on the bridge over Lake
Ponchetrain in La. because the piers were eroding, and not just in the
ship channel, just the wave action will do it over time.

From 99% of your posts, you prove you do not know ****! Sure, wear and
tear
from the water eroding the concrete causes problems. Even bigger
problem
you do not seem to understand is the rebar rusts and expands and breaks
the
concrete. Normal wear and tear.

Haaahaaa!! I know more about concrete than you will EVER know!! My
thesis was on composite reinforcing in concrete!!! Now, your idiotic
"rust" issue. That is NOT an inherant problem if constructed properly.
EVENTUALLY, yes, the rebar will rust. BUT, if constructed following
normal guidelines, and following ACI 318, which CLEARLY details
minimum coverage for a given situation, and is backed by years and
years of research, you will find that it is not an issue.

But the USCG and the locals going for a
$27,000 fine for causing a wake? IT IS THE BRIDGE OWNERS RESPONSIBILITY
TO
MAINTAIN THE BRIDGE! They have used the revenues from the bridge for
non
bridge items. No reserve to fix the bridge. Bridge is unsafe for
boats.
Boaters should sue the local bridge district. If a boater gets a
$27,000
fine, would be cheaper to sue the bridge owners than paying the fine.
Just
like the San Francisco Bay Bridge. Toll $2. maintenance costs for
bridge
less than 25 cents per car. Local politicians want an election to raise
the
toll some more for mass transit, etc. Screw the minority who has to
travel
over the bridge. They get outvoted.

I could care less about the politics. As for the technical aspect, YOU
are the one who doesn't know ****.

Fine for creating a wake: $27,500
 

bass,
Okay, thanks, you seem to have a handle on this bridge construction
thing, way more than I know about it. But don't you think that they can
build bridges that aren't bothered by normal wave action, for at least one
of our life times? For example, when I lived on the lake, my sea wall was
strong enough that normal storms didn't phase it. It had to be strong enough
for the normal storm, so a boats wake didn't really bother me. On the other
hand I could only have had a boat if I had a hoist. I didn't have one but my
next door neighbor did, he could only launch or retrieve his boat if the
waves were calm. If he left when they were calm, and he returned when the
chop was up, he docked his boat at the neighbor across the street who lived
on a canal. That hoist will beat your boat to death before you get it up.
As a side note; I asked the neighbor on my other side who didn't have a
hoist either. I was admiring my other neighbor's hoist and asking my second
neighbor about it. He was telling be that it cost around $8,000. I
commented that I didn't think that was too bad it that in the long run it
would be cheaper than in a marina. He said, "Yea they're nice, we used to
have one. At least until one spring when the ice flows blew in here and
took out the hoist. Than he explained that you can't insure against ice
damage. Well I never put in a hoist. :-(. But such is the sea, and Lake
Saint Clair is a small sea.
Paul

"basskisser" wrote in message
om...
"Paul Schilter" paulschilter@comcast,dot,net wrote in message
...
bass,
I don't claim to know bridge construction, but wouldn't it be
founded on
bed rock, or at least huge caissons?

Nope, not at all, Paul. Restrained soils in that area are safely able
to handle somewhere in the vicinity of of 3,500 pound per square inch
pressure. Also, being mostly sand, they are not subject to
expansion/contraction. All this to say that, no, there is no reason to
found on bedrock, or caissons. Even if the soils were crappy, and it
were founded on caissons, likely the caissons in that area would not
be founded on bedrock. They would use skin friction to support the
design loads.