Another engineering question... (extra credit)

[Mr Bogus]

Below is a "water bridge" it was a solution for a waterway that had to cross another waterway.. It is only meant to carry barges and other watercraft..

So, here is the question..

As engineers design the supports for this "waterbridge" they must evaluate and build for the loads they will take from the waterway..

Now what loads do they need to take into consideration:

1. The weight of just the bridge
2. The weight of the bridge and the water
3. The weight of the bridge, the water, and the traffic crossing the bridge.

 

[theskaz]

at first i thought that it would be just water and the bridge itself since anything floating would dispace the water and not caused any extra weight. Upon rereading what i wrote that sounds retarded. if you have a bowl of water on a scale and add anything with weight that would actually float, the scale will show an increased weight.

at least i think so.....

 

[zellabusa]

I would think number 2. The weight of whatever craft crosses the bridge will just displace the water, right?

 

[theskaz]

I would think number 2. The weight of whatever craft crosses the bridge will just displace the water, right?

i thought about that too. but if the water weighs so much.... ok scratch that..

you might be right. if the water displaces at either end (not over the sides) it will cause less total water to be on the supports. If a boat is there and displaces so many gallons of water, does the boat weigh more or less than the dispaced water? it might be equal. ok as of right now i change my answer to my original thought.

 

[F=MA]

at first i thought that it would be just water and the bridge itself since anything floating would dispace the water and not caused any extra weight. Upon rereading what i wrote that sounds retarded. if you have a bowl of water on a scale and add anything with weight that would actually float, the scale will show an increased weight.

at least i think so.....

The water should be displaced to an area where the bridge does not support it...#2.

 

[badazgtp]

They would have to take into cosideration of the pressure of the water caused by the object in the water. The object is taking space and causes the water to move to a different location, which puts pressure on the walls of the bridge. Hope that makes sense.

 

[theskaz]

They would have to take into cosideration of the pressure of the water caused by the object in the water. The object is taking space and causes the water to move to a different location, which puts pressure on the walls of the bridge. Hope that makes sense.

actually i dont think it would add pressure to the walls because it would be easier for the water to back up or go forward than to push on the wall. if that makes any sense.

 

[Mr Bogus]

Yes it is number 2... if it was a "closed" pool supported soley on the piers, yes all 3 but it is an open water way so displaced water goes up/down stream.. I missed this question on an exam... sort of stuck with me..

 

[badazgtp]

actually i dont think it would add pressure to the walls because it would be easier for the water to back up or go forward than to push on the wall. if that makes any sense.

Gotcha. Makes sense. I was just thinking of the wake also from the water being pushed, but I guess if they stayed at a low enough speed, it wouldn't be a problem. OH Well, I tried

 

[Poppy]

I would think number 2. The weight of whatever craft crosses the bridge will just displace the water, right?

I'll agree with this......

 

[turbobusa2000]

Wouldn't they have to consider all 3 because even though the water is being displaced, the weight of the vessel could be heavier than the water it's displacing.

 

[jdsbusa]

Wouldn't they have to consider all 3 because even though the water is being displaced, the weight of the vessel could be heavier than the water it's displacing.

Not unless it was enclosed like stated above. Think of it like a river vs a swimming pool. Water can go infinitely (to a point) forward or back in a river, not so in a pool.

 

[theskaz]

Wouldn't they have to consider all 3 because even though the water is being displaced, the weight of the vessel could be heavier than the water it's displacing.

buoyancy. the vessel will sink until it displaces enough water to equal out.




i think.....

 

[jdsbusa]

buoyancy. the vessel will sink until it displaces enough water to equal out.




i think.....

correct, assuming the object is designed to float - a steel ball doesn't float too well. If it's meant to float, design plays a major role to produce the displacement, otherwise the water makes its way over the top and well.....it sinks.

 

[Mr Bogus]

correct, assuming the object is designed to float - a steel ball doesn't float too well. If it's meant to float, design plays a major role to produce the displacement, otherwise the water makes its way over the top and well.....it sinks.

hence the careful wording of the question..

 

[dadofthree]

You got us doing your homework dude ?

 

[Projekt]

Excellent! We learn something new everyday at hayabusa.org.

 

[BusaWizard]

And to think; most of you got it without a 3.8 GPA. Ooooooooooooops did I say that?

 

[chrisjp]

uhhhhh ok.....

 

[Dino]

Isn't a "Water Bridge" commonly known as an Aquaduct?