Then is there still some rain in the vicinity? Seems as though if things had dried out again, the river would have fallen all the way?
That design of tug has always had me curious. It would seem as thought they'd be awkward, top heavy. Are they ballasted to keep from trying to tip?
They were still letting water out of reservoirs way up in North Texas a couple weeks ago. Although it takes a while for it to get down here. Things may be down to normal in a week or so. Till the next flood anyway.
Yeah, but the diesel, fuel and other machinery are set low in the hull along with other ballast. The superstructure is relatively light weight. As long as there is no strong wind to make it act like a sail, they are OK.
If I recall that particular incident..... This was one, about same time frame, but I don't think this was it: http://www.professionalmariner.com/...e-after-drunk-bridge-tender-lowered-the-span/ This is it: April 28, 1979 — the CAHABA Tombigbee River, the Old Rooster Bridge
Still work going on around the bridge site. Cross bracing is being welded between the steel pilings on both pier sets. The old masonry piles are pretty much demolished. The river level is down enough that they can add bracing farther down. The large barges appear to be made up of sections that can be trucked in and then hauled away again on the highway. You can see one detached section half way up the bank on the right. You can see the superstructure of one of the little tug/tow boats way up on the bank on the right. I guess those were trucked in also in pieces.
Oh, yeah. Full speed, no slow orders. Bridge workers beware. The locomotives do blow a series of very short blasts as they go by.
Back in train order days, they would issue an order which said to the effect of "sound horn and ring bell freely while passing through these limits".
These days there's something called a Form B where you have to call the foreman in charge. He'll then tell you whether you can pass and at what speed. Track warrents for bulletins are issued to every train to advise them of Form Bs and other track conditions. Flags are also placed by the work crew at the limits of their work zone and usually two miles before that, too.
Here is a shot showing about where the old river bank was before it washed away in the last flood. You can see some sticks coming up out of the water where vegetation was growing along the water's edge. Many cubic yards of dirt washed away in a matter of hours exposing the bridge abutment and the trestle bents leading up to it. The water flow eventually scoured out below the second pier out that was normally at the water's edge.
If they don't re-fill that lost area, it would seem to me the current will be impacting piers at an angle much different from the method they'd normally be installed against a stream.
This shows the old cut stone pier that is still in place. It has a huge concrete footing at its base to diminish scouring during flood events.
With the round pipe piers, I would think the direction of the current would not have as much effect as it did with the solid flat masonry piers.
I seriously doubt it. Bedrock is over 1/4 mile down. They probably go down a few hundred feet, much deeper than the original piles placed over a hundred years ago. I was talking to a friend who is an architect about these pipe piles. He said there was a algorithm for calculation how deep a pile had to go to support a given weight depending on the type of soil. The sky scrapers in down town Houston are all supported only by piles driven into the sediment a calculated depth. The adhesion of the side surfaces of the piling to the soil provide a whole lot of the resistance along with the cross section of the base. The pipe piles can be driven much farther down because the relatively thin walls provide little cross sectional resistance when driving them down. On a bridge pile application, they fill them with concrete to a few yards below the soil surface and rely on the column of compacted sediment below that to support weight. The upper concrete fill provides lateral strength to keep the pipe from bending above the ground as well as providing anchor support for the cast concrete cross beams.
They are pulling up the piles that were supporting the crane platform beside the bridge. They attach the shaker/vibrator to the top, get the pile dancing, and then jerk it out of the mud.
