Quantcast

Determining Bridge Clearance?

Help Support Engineer Boards:

mudpuppy

Charter Member
Joined
May 16, 2007
Messages
5,759
Reaction score
1,607
Location
Michigan
Asking for Mrs. mudpuppy....  how do you determine the minimum clearance of a bridge above a navigable waterway?  She says some of the waterways have a published height by the Coast Guard, but the one she's working with does not.

As an EE I'm totally lost here.

 
Last edited by a moderator:

kevo_55

The Beer Baron
Joined
Dec 22, 2006
Messages
5,724
Reaction score
1,698
Location
MSP
The AASHTO Bridge design code should have it in there.

I'm a buildings guy though.

 

bwin12

Member
Joined
May 8, 2017
Messages
99
Reaction score
25
I was involved in Design Build project in Alaska once. I wish I could find the direct quote from the Forest Service but it went something along the line of "This river is known to have iceberg travel due to calving from the nearby upstream glacier. The nearby downstream Railroad Bridge has but affected by glancing blows periodically, so please design this bridge slightly higher than the RR Bridge. We opine that height will be sufficient.".

My answer, based on experience- guess, then go a little higher for safety.

 

mudpuppy

Charter Member
Joined
May 16, 2007
Messages
5,759
Reaction score
1,607
Location
Michigan
I was involved in Design Build project in Alaska once. I wish I could find the direct quote from the Forest Service but it went something along the line of "This river is known to have iceberg travel due to calving from the nearby upstream glacier. The nearby downstream Railroad Bridge has but affected by glancing blows periodically, so please design this bridge slightly higher than the RR Bridge. We opine that height will be sufficient.".

My answer, based on experience- guess, then go a little higher for safety.


My wife was finally able to get a hold of someone from the Corps of Engineers yesterday and this was basically their answer.  Except they don't know how high the next bridge over is.  Apparently the Coast Guard is the ultimate authority on this (for navigable waterways), but they're furloughed.

 

P-E

Member
EB Supporter
Joined
May 21, 2014
Messages
21,504
Reaction score
1,972
Location
Boston
This method works  


nope not enough

 
Last edited by a moderator:
Joined
Dec 13, 2016
Messages
522
Reaction score
99
Location
New Jersey
Asking for Mrs. mudpuppy....  how do you determine the minimum clearance of a bridge above a navigable waterway?  She says some of the waterways have a published height by the Coast Guard, but the one she's working with does not.

As an EE I'm totally lost here.
Whoever governs the waterway should be able to provide the answer. They should know what the other bridge heights are and what suze water crafts usually travel that water path.  Ideally,  you would want to at least match or be higher than the next bridge up and down stream from where you are.

 

Latest posts

Top