I am trying to figure out how to quickly calculate a surcharge depth based on FG at CL to OG along a corridor. Attached is an example of what I'm trying to figure out.

Surcharge depth is based on the difference of FG to OG times 0.45. And as you go up and down the corridor the depth changes. The way I was able to get close seems entirely to difficult. Also, not exactly correct. I remember something similar we did at PUG. But with the wall height times 0.80 to get the excavation width.

I attempted to create a quick model with a alignment/vertical and a OG surface. In my example I was able to get my nodes to move up and down and in and out based on depth as shown as node 1 and 2. Node 3 is a mirror of 1 and 2. But that is where I am stumped. How to calculate the x 0.45 of the variable depth without going through all of the additional steps. And get it exact not just half the depth like in the example. (I'm pretty sure thats what I came up with).

Any help from the pro's out there would be awesome!!

Tysen

Tysen - Great Question and I will also add this to the Advanced Corridor Modeling Blog as a follow up here

What I would do is use the "Test Shot Approach" (similar to the strap length for MSE Walls concept) which involves taking the Top of Wall and Base of wall points and doing a Slope Slope intercept where the Slope of the line from Wall Top is at 0.8:1 (assumes Strap Length is 0.8x Wall height) and the slope from the base of wall is 0%. This computes you a node X that you dont include in a material layer. Now when you want to create an Offset /Elevation from the Inside Base of Wall which is that 0.8x the height of wall you can use Node to Node for the offset and measure the first node as X and the second Node as the base of wall (outside) point - this gives you the distance - either a positive or negative value - reverse the nodes if you need the opposite of what you got. then for Delta Elevation you enter 0 to maintain the base of wall elevation.

Now in your case you want the following (I think I read this right ...)