How to enter the Sea surface and Sea-bed floor, and current profile depths into an AutoPIPE model?
Given the following example model of piping connected to equipment resting on the sea-bed floor and Water Depth is 50 ft:
What are the values entered into the Wave Load case dialog for each of the following:
a. Water Elev ?
b. Depth ?
c. Water Depth for current profile and marine growth assuming 5 equal distances ?
First start with a hand sketch, Draw a horizontal line on the page, label this Origin vertical axis ( assume vertical axis is Y, Y = 0)
From the example model, piping is resting on sea-bed floor, Global Y = -25, draw another horizontal line on the diagram representing the sea-bed floor and label it:
Next locate Water Surface (ex. Sea-bed location [ Y = -25] + Water Depth [50] = Water Surface [Y =+25]) or Sea-bed relative to the Water Surface, draw another horizontal line, label line as Water Surface level and enter the vertical axis value where this imaginary level occurs:
To locate the Current and Marine growth, divide the depth into 5 sections(ex. 50 / 5 = 10). Add depth values consecutively:
Water Depth #1: 10
Water Depth #2: 10 +10 = 20
Water Depth #3: 20 +10 = 30
Water Depth #4: 30 + 10 = 40
Water Depth #5: 40 +10 = 50
Enter values into Wave Load dialog screen:
What part of the piping is above the sea-bed floor?
What part of the piping is below the sea-bed floor?
What part of the piping is above the Water Surface?
Is the Wave load Water elevation and Depth located correctly?
Not sure, than let us look at a graphic representation of the Wave load,
Using AutoPIPE CONNECT 11.x and higher
Show Ribbon> Labels> click on "Water Surface and Sea Level" icon
Using AutoPIPE CONNECT 10.x and lower
View> Show Options> Properties listing> Enable Water Surface and Sea Level option, push OK button
A Blue translucent box is displayed to show exactly where the Water Surface was located and where the sea-bed level was located. Any piping inside of the box is assumed to be affected by the Wave load case. Any piping above or below the blue box is not affected directly by the Wave loading.
If the Wave load case height or depth has been modified use Show Reset button to remove the blue box and perform the steps above to again display the blue box.
In this example, clearly see that the highlighted red piping is half in the box and half below the box. That is because the pipe radius was NOT taken into consideration when calculating the sea-bed floor, the equation for pipe resting on sea-bed should have been:
Global Y value of piping center-line + radius of pipe = sea-bed floor(-25 + .5 = -25.5)
The Water Surface an Sea-bed are imaginary elevations in the model similar to the ground elevation for Wind loads. Both the Water Surface and Sea-bed floor can occur at any point along the vertical axis elevations. Drawing a sketch, to clearly locate the Origin, Water Surface, and Sea-bed floor relative to the pipe is important before opening the Wave dialog. To make things easier, use origin elevation Y = 0 as either the Water Surface or Sea-bed floor, then measure in the respective direction to find the other elevation and locate pipe accordingly. Using the "Water Surface and Sea Level" show option is a great tool to verify the Wave location relative to piping.
"Wave" Load Case
Bentley AutoPIPE