Does anyone know how to estimate the forces imparted to a bridge pile bent due to waves under hurricane winds?
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Forces due to ocean waves in high wind 8
- Thread starter Polecat
- Start date
msquared48
Structural
I believe that there is a Nafac publication on that subject. I will see if I can find it.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
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3
- #3
For specific or detailed information you may need to talk to an ocean engineer. The base water level during a hurricane may rise (storm surge), assuming waterway is connected to the ocean. In open water, the wave height & period that is generated is a function of wind speed, wind direction & duration. Waves are modified (higher & closer together) as they approach shore and water depth decreases. You may be able to find this "design wave" information for your location, try the local officials, disaster or hazards documents.
Forces can then be estimated for a design wave height. Will depend on pile/pier diameter, primarily. The "Shore Protection manual" by the Corps of Engineers will cover all this.
Forces can then be estimated for a design wave height. Will depend on pile/pier diameter, primarily. The "Shore Protection manual" by the Corps of Engineers will cover all this.
- Thread starter
- #5
Thanks to all of you for your response.
M^2, I'd be interested in that Nafac publication if you find it ---- CarlB, I'll try to obtain the C of E publication on shore protection. Thanks for the tips.
Ron, I did back into the number and that's what jolted me.
This is a frame consisting of two 24" sqr prestressed piles connected at the top by a tie beam such that a full moment connection is developed there. I chose a point about ten feet below the sea bottom that would approximate the maximum moment developed in the pile and backed into the load that would be required near the top to simulate the force imparted to it by the wave action.
The result was a load that was less than 1/3 of the number that appeared on the original design drawing, leading me to question how that number was arrived at originally. In this case, "originally" means 1959.
M^2, I'd be interested in that Nafac publication if you find it ---- CarlB, I'll try to obtain the C of E publication on shore protection. Thanks for the tips.
Ron, I did back into the number and that's what jolted me.
This is a frame consisting of two 24" sqr prestressed piles connected at the top by a tie beam such that a full moment connection is developed there. I chose a point about ten feet below the sea bottom that would approximate the maximum moment developed in the pile and backed into the load that would be required near the top to simulate the force imparted to it by the wave action.
The result was a load that was less than 1/3 of the number that appeared on the original design drawing, leading me to question how that number was arrived at originally. In this case, "originally" means 1959.
Polecat...your original post led me to consider something besides concrete, since you indicated that it bent.
Your number might be closer than you think, since the wave action likely caused some scouring, thus fixity would be achieved at a lower depth than was perhaps considered in the original design.
Is the actual water depth the same now as when they were constructed? If so, is it possible that fixity was considered in the original design to be higher than we would currently.
Your number might be closer than you think, since the wave action likely caused some scouring, thus fixity would be achieved at a lower depth than was perhaps considered in the original design.
Is the actual water depth the same now as when they were constructed? If so, is it possible that fixity was considered in the original design to be higher than we would currently.
Here's a lecture with an example on application of the Morison equation:
I assumed "bent" was used to describe a structural member/shape, rather than past tense of "bend".
I assumed "bent" was used to describe a structural member/shape, rather than past tense of "bend".
- Thread starter
- #9
CarlB, you were correct. I meant to describe a "rigid frame bent," rather than a "bent pile." Guess I'm just too much old school.
And thanks for the lecture info. I downloaded the ppt presentation and will take time to absorb it later. Looks like just what I need.
Many thanks.
And thanks for the lecture info. I downloaded the ppt presentation and will take time to absorb it later. Looks like just what I need.
Many thanks.
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5
- #10
Since the I-10 span collapses due to Ivan and Katrina, I've found this document to be helpful.
Regards,
Q
Regards,
Qshake
![[pipe]](/data/assets/smilies/pipe.gif "[pipe] [pipe]")
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
Regards,
Q
Regards,
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
Why thank you Ron. I needed a purple star for the Christmas tree!
Did you put up the palm tree this year?!
The way the weather is in the central midwest, the snow is only a figment of my imagination and so is the fact that I've walked uphill to and fro school. If I tell that story nowadays, I get strange looks and not for the obvious reason. It's all that hot-air from politicians causing midwest warming!
Regards,
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
Did you put up the palm tree this year?!
The way the weather is in the central midwest, the snow is only a figment of my imagination and so is the fact that I've walked uphill to and fro school. If I tell that story nowadays, I get strange looks and not for the obvious reason. It's all that hot-air from politicians causing midwest warming!
Regards,
Qshake
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
- Thread starter
- #14
Very good report on Katrina, Q, it will be quite useful. Thanks.
Dik, what articles are you refering to, the same ones that were mentioned above in this thread, or something else?
I really appreciate you guys responding to this.![[thumbsup2]](/data/assets/smilies/thumbsup2.gif "[thumbsup2] [thumbsup2]")
Dik, what articles are you refering to, the same ones that were mentioned above in this thread, or something else?
I really appreciate you guys responding to this.
Polecat... if you modify the URL for the site and change it to lecture20, 18,... etc. There's a whole course of instruction on wave action...
I often do that when I get a good link... sometimes even end up in the directory with more stuff...
Dik
I often do that when I get a good link... sometimes even end up in the directory with more stuff...
Dik
msquared48
Structural
Sorry, but I could not find the specific Navfac publication. I do have a 100 page printout of the wave force section, but it's probably 30 years old or more.
Sounds like you have solved your problem though. Good luck.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Sounds like you have solved your problem though. Good luck.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
I believe the NAFAC publiations Mike refers to are DM-26 series. Many can be found at
"classic" 1984 Shore Protection Manual(SPM):
Coastal Engineering Manual, which supersedes the SPM:
"classic" 1984 Shore Protection Manual(SPM):
Coastal Engineering Manual, which supersedes the SPM:
- Thread starter
- #18
Many thanks to all of you for inundating me with all this valuable info.
Looks like it's back to school again for a while.![[smarty]](/data/assets/smilies/smarty.gif "[smarty] [smarty]")
Looks like it's back to school again for a while.
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