build a bridge to build a bridge.....
 

Seems like the old way is better.

http://www.pddnet.com/news-photo-of-...bridge-010511/


Thank You,
Randy

Remove 333 from email address to reply.

build a bridge to build a bridge.....
 

Randy wrote:
Seems like the old way is better.

http://www.pddnet.com/news-photo-of-...bridge-010511/


Thank You,
Randy

Remove 333 from email address to reply.

is that the project where they're only using chinese steel?

build a bridge to build a bridge.....
 

On 1/7/2011 6:28 AM, Randy wrote:

Seems like the old way is better.

Well as per the video, the suspension bridge is self anchored, not
anchored to shore. Maybe that has something to do with seismic issues,
designing to survive "the Big One"...

I almost always take the Benicia-Martinez that crosses the Carquinez
Straight when returning from the SF Bay Area. It's also being replaced
and I've seen that crane fairly close as I drove past. It is MASSIVE!


Jon

build a bridge to build a bridge.....
 

On Jan 7, 5:13*pm, Jon Anderson wrote:
On 1/7/2011 6:28 AM, Randy wrote:

Seems like the old way is better.

Well as per the video, the suspension bridge is self anchored, not
anchored to shore. Maybe that has something to do with seismic issues,
designing to survive "the Big One"...

I almost always take the Benicia-Martinez that crosses the Carquinez
Straight when returning from the SF Bay Area. It's also being replaced
and I've seen that crane fairly close as I drove past. It is MASSIVE!

Jon

Technically that new bridge is NOT a suspension bridge, but a cable-
stayed bridge.

As far as I can tell from the video there are no suspension cable
catenary; all cables from the towers go directly to the road deck.
Hence cable-stayed. There are quite a few bridges of this type in the
USA and the world.

Wolfgang

build a bridge to build a bridge.....
 

On Jan 8, 2:52*pm, Joe Cool wrote:
On Jan 7, 5:13*pm, Jon Anderson wrote:

On 1/7/2011 6:28 AM, Randy wrote:

Seems like the old way is better.

Well as per the video, the suspension bridge is self anchored, not
anchored to shore. Maybe that has something to do with seismic issues,
designing to survive "the Big One"...

I almost always take the Benicia-Martinez that crosses the Carquinez
Straight when returning from the SF Bay Area. It's also being replaced
and I've seen that crane fairly close as I drove past. It is MASSIVE!

Jon

Technically that new bridge is NOT a suspension bridge, but a cable-
stayed bridge.

As far as I can tell from the video there are no suspension cable
catenary; *all cables from the towers go directly to the road deck.
Hence cable-stayed. *There are quite a few bridges of this type in the
USA and the world.

Wolfgang


To carry on: This type of bridge can and has been built without the
"support bridge" to hold it up. I seem to recall that a similar
bridge was built some years ago across the Mississippi River without
support steel; but I could be mistaken.

To do so the towers are built first (as usual) and the road bed
sections cantilevered out from each side of the tower while supported
in position by a crane. At this point the cable stay for that section
is installed on each side of the tower to keep things in balance. The
crane is then moved to hoist the next section into position. Rinse and
repeat as required.

Why the constructors chose to go with this "auxiliary bridge" routine
one can only guess at.

If anyone here knows of the reasons for this construction methodology
I'd be pleased if it is pointed out here.

Wolfgang

build a bridge to build a bridge.....
 

On 1/8/2011 3:47 PM, Joe Cool wrote:

Why the constructors chose to go with this "auxiliary bridge" routine
one can only guess at.

Pure speculation on my part, but there is still a fairly large volume of
good size container shipping passing under the bridge. Maybe, just
maybe, this approach lets the lifting barge get out of the way sooner as
they only need to get it onto the support bridge and don't have to stay
there hold up the section while the support cables are installed.
And maybe given the size of the sections and height, there might not be
two such lift barges available to keep the load balanced?


Jon

build a bridge to build a bridge.....
 

On Sat, 8 Jan 2011 15:47:13 -0800 (PST), Joe Cool
wrote:

Technically that new bridge is NOT a suspension bridge, but a cable-
stayed bridge.

Not quite. It is a sort of a hybrid between the classic suspension
bridge and the cable stayed bridge. If you look closely at the
pictures, you can see that all cables except the outer ones attach to
the outer cable. Here is a picture of another such bridge, where the
cable are clearly visible:

http://www.newsworld.co.kr/cont/0207/50.html

To carry on: This type of bridge can and has been built without the
"support bridge" to hold it up. I seem to recall that a similar
bridge was built some years ago across the Mississippi River without
support steel; but I could be mistaken.

The tallest bridge in the world, the Millau Viaduct, is a cable stayed
bridge. It was built using support towers between the actual towers,
but no support bridge.

To do so the towers are built first (as usual) and the road bed
sections cantilevered out from each side of the tower while supported
in position by a crane. At this point the cable stay for that section
is installed on each side of the tower to keep things in balance. The
crane is then moved to hoist the next section into position. Rinse and
repeat as required.

In the case of the Millau Viaduct, the road sections were slid in
place using a hydraulically operated wedge system, sliding on Teflon
bearings. This is probably why the intermediate support towers were
necessary.
--
RoRo

build a bridge to build a bridge.....
 

On Jan 9, 9:54*am, Robert Roland wrote:
On Sat, 8 Jan 2011 15:47:13 -0800 (PST), Joe Cool

wrote:
Technically that new bridge is NOT a suspension bridge, but a cable-
stayed bridge.

Not quite. It is a sort of a hybrid between the classic suspension
bridge and the cable stayed bridge. If you look closely at the
pictures, you can see that all cables except the outer ones attach to
the outer cable. Here is a picture of another such bridge, where the
cable are clearly visible:

http://www.newsworld.co.kr/cont/0207/50.html

To carry on: *This type of bridge can and has been built without the
"support bridge" to hold it up. *I seem to recall that a similar
bridge was built some years ago across the Mississippi River without
support steel; *but I could be mistaken.

The tallest bridge in the world, the Millau Viaduct, is a cable stayed
bridge. It was built using support towers between the actual towers,
but no support bridge.

To do so the towers are built first (as usual) and the road *bed
sections cantilevered out from each side of the tower while supported
in position by a crane. *At this point the cable stay for that section
is installed on each side of the tower to keep things in balance. The
crane is then moved to hoist the next section into position. Rinse and
repeat as required.

In the case of the Millau Viaduct, the road sections were slid in
place using a hydraulically operated wedge system, sliding on Teflon
bearings. This is probably why the intermediate support towers were
necessary.
--
RoRo


After having another look at the OP video on a large screen, I concur
that it is indeed a true suspension bridge that is being constructed.

Nonetheless, I still question the need for the "auxiliary" bridge to
support the road deck. Perhaps it is for scheduling reasons ie. it
permits faster erection with less impediment of the shipping channel.
Or perhaps the tides and/or currents are too great for the stability
of the free-floating crane.... Just conjecture I agree.

The first large-scale suspension bridge is the Brooklyn Bridge in New
York, built in the 1880's now over 120 years old! This bridge was
erected without an "auxiliary" bridge. The construction of this
bridge is an interesting story in itself. Compare this bridge to the
Tacoma Narrows Bridge!

Wolfgang

build a bridge to build a bridge.....
 

Joe Cool wrote:
On Jan 8, 2:52*pm, Joe Cool wrote:
On Jan 7, 5:13*pm, Jon Anderson wrote:
On 1/7/2011 6:28 AM, Randy wrote:

Seems like the old way is better.

Well as per the video, the suspension bridge is self anchored, not
anchored to shore. Maybe that has something to do with seismic issues,
designing to survive "the Big One"...

I almost always take the Benicia-Martinez that crosses the Carquinez
Straight when returning from the SF Bay Area. It's also being replaced
and I've seen that crane fairly close as I drove past. It is MASSIVE!

Technically that new bridge is NOT a suspension bridge, but a cable-
stayed bridge.

As far as I can tell from the video there are no suspension cable
catenary; *all cables from the towers go directly to the road deck.
Hence cable-stayed. *There are quite a few bridges of this type in the
USA and the world.

To carry on: This type of bridge can and has been built without the
"support bridge" to hold it up. I seem to recall that a similar
bridge was built some years ago across the Mississippi River without
support steel; but I could be mistaken.

To do so the towers are built first (as usual) and the road bed
sections cantilevered out from each side of the tower while supported
in position by a crane. At this point the cable stay for that section
is installed on each side of the tower to keep things in balance. The
crane is then moved to hoist the next section into position. Rinse and
repeat as required.

Why the constructors chose to go with this "auxiliary bridge" routine
one can only guess at.

If anyone here knows of the reasons for this construction methodology
I'd be pleased if it is pointed out here.

Union labor, on the taxpayer dime.

Cheers!
Rich