Shoring Suite Question

[Guest090822]

Does anyone have experience with area loads in the Shoring Suite software?

The user manual section 9.4:

9.4 Area Loads

"Buildings and large equipment are typical area loads. When they are placed near a sheet pile wall, the lateral pressure distribution on the wall can be calculated as shown in the figure below. The lateral pressure due to an area load can be calculated by using integration of Boussines equation (Reference: Poulos & Davis, “Elastic Solutions for Soil & Rock Mechanics”, Page 54). However, the Boussines equation is an elastic solution, which generates a relatively higher lateral pressure. Since soils are plastic materials, we think Teng Equation for strip loading is more suitable for the shoring calculation. Therefore, [highlight #FCE94F]a length factor[/highlight] is added to Teng Equation for area loading calacultion. When the length (L) is infinitive long, the equation is the same as that for strip loading."

They are taking the basic equation for a strip load and reducing it somehow because the load has a defined area. I've never come across this method and am curious about it. I was checking the pressures for a project by hand and was consistently off by a lot so I looked in the manual and found this information.

Is anyone familiar as to how they determine this factor?

 

[r13]

You might have to ask the developer of the program, since he is the one made the assumption and made up a factor, which does not seem widely used. Also ask, and check his references.

 

[PEinc]

Contact Civiltech at supportatCiviltechdotcom. Ask for them to send you the verification hand calcs for the surcharge analyses. Be specific about which type of surcharge load you want (e.g., strip, area, line, point, etc.).

http://www.PeirceEngineering.com

 

[Guest090822]

I guess this same question was asked on this forum back in 2009. The answer below explains it, and I was able to match the program:

We use the following equations:


1. Pstrip = k* Q/pi * (beta-sin(beta)*cos(2alpha))

where k=1 for very flexible wall. k=2 for rigid wall

This equation can be found in P16 of USS manual. It is modified Boussinesq equation and widely used for shoring design. It called Wayne & Teng Equation. Wayne & Teng Equation is widely used in shoring design. We found that using Boussinesq equation to calculate Area Loading and Pint Loading do not match the results from strip loading calculation of Wayne & Teng Equation. We have to modify Wayne & Teng Equation for area loading to keep the results consistent.

Following are our equation:

2. Parea = f * Pstrip
Where f is length factor:
f = 1- 1/(0.25 * L/(X+1) +1)
L - length of area loading; X - Distance to the wall.
When L is infinitive, f = 1, Parea=Pstrip

We plotted curve from Boussinesq equation and use this curve to scale down to fit Wayne & Teng Equation. Then we get the above equation.

3. Ppoint = Parea when Length=1 and Width=1.