How do I add a new soil layer?

1. Open the Soils page of the define box by double clicking the soil on the active side of a design.
2. Click the New Layer button:
3. Enter the depth of the top of the layer in the depth box.
4. Select a soil from the database by clicking the down arrow to the right of the Name box. The soil parameters may be edited. Alternatively, enter a new soil name and properties in the relevant boxes without selecting from the database.
5. Click the Apply button:
6. The new layer is not added to the design until the Apply button is clicked.

 

How do I place a support above ground level?

1. Open the Wall page of the define box by double clicking the sheet pile.
2. Enter an Upstand in the box provided (eg. 1.0).
3. Open the Supports page of the define box.
4. Enter a negative value for the support position (eg. -0.5). The support must be within the upstand.

 

How do share load between two supports?

1. Open the Supports page of the define box by double clicking an existing support.
2. Place two frames close together (0.5m or nearer) using the Frames grid.
3. Select the lower of the two supports in the grid.
4. Click the Share load check box. The total linear load on the two frames is shared equally. A link is displayed in the main design diagram to indicate that load is being shared.

 

How many levels of wales may be entered?  And what's the difference between braces and walers?

Twenty (20).  The options between braces and walers is really for presentation purposes; it informs the installer what kit is being installed.   However, the waler does allow angled struts/anchors which the brace does not (but note that the displayed load is the linear load on the waler/brace, not a strut load).

 

Why does the pressure remain constant when a design is edited?

Changes in soil parameters, water tables, etc sometimes produce no change in the calculated net pressure.

This is probably due to the presence of soils with a high cohesion. In such cases, the calculated soil pressure may be negative, and the pressure values are being calculated using the minimum equivalent fluid pressure, MEFP.

 

How do I change units?

You can change units in the Setup page of the define box.  The best time to do this is when you first open a job.  Doing so later can create problems with the database; the only way to deal with it then is to reinstall the program.  If you work consistently in U.S. units, the best way to switch over is to do as follows when you first use the program:

1. Open a new job.
2. Double click on the center of the screen, in the drawing.
3. Click the "Setup" tab in the define box that appears.
4. Click on the "Imperial/U.S." button.

You can then proceed to enter the rest of the job information.  If you do have to reinstall the program and have made entries to the database, you can do the following:

• Select the unit setting which gives metric VALUES (eg. E should be 2.1E8).
• Exit the software.
• Copy the files Client.db, Sheet.db and Soil.db from the Pile Buck\Data folder to another location. These will hold metric values.
• Uninstall SPW911 and ensure the folder Program Files\Pile Buck is deleted.
• Reinstall SPW911. It should be already set to metric units.
• Copy the files Client.db, Sheet.db and Soil.db, which you copied above, back to the Pile Buck\Data folder.

 

How do I model soldier piles using SPW 911?

We have an article on this subject.
Please contact us for a downloadable PDF.

 

What kind of surcharges can be input into the program?

Only uniform surcharges can be input into the program.  The program does not consider point loads, strip loads, etc.

 

When driving a cofferdam to rock (for keying bridge bent footings into rock), how do I show this in the define soil layers screen?

Define a new soil with appropriate properties for rock, e.g., high cohesion, etc.

 

Does SPW 911 handle broken back fills?  Horizontal loads to be applied to the sheeting to model guardrail impacts?

No.

 

I have a situation where the soil at the base of the sheeting is sloping down and away from the base at a 3:1 (3 horizontal, 1 vertical) slope.  How can this be modeled in SPW 911?

It depends very much on the ground. In cohesionless soils, you could draw a line from the bottom of the wall at an angle of phi (angle of internal soil friction) to the horizontal.  Draw a horizontal line from where this meets the slope on the passive side back to the wall.  The distance from this point to the original point (where the soil meets the wall) is the height "X" which you can ignore. With cohesive soils, the problem is not so acute, where the shear strength is much higher.  Some provisions would probably need to be made in the case of soft clays, but it would be up the judgment of the engineer.

 

Can SPW 911 be used to design wood or concrete sheeting walls?

Yes, if they enter appropriate properties (E & I values especially).

 

I entered data for a new sheet pile section into the database while analyzing a wall design.  While analyzing the wall, I realized I needed to change some of the sheet pile properties.  But there's no change in the results from the program.  What's going on?

You need to either a) save the results, exit the analysis and restart it or b) change the sheeting momentarily to another section, then change it back to the one you're working on.

 

Can I work to elevation vs. depth?

No, the datum is fixed at ground level.  To change this would interfere with the calculation methods of the program.

 

Why would the anchor force for a single propped or anchored bulkhead be greater than the maximum shear?

Any concentrated force on a beam -- and this is what you're basically dealing with with a sheet pile -- creates a discontinuity in the shear diagram equal to the magnitude of the concentrated load.  Thus, the difference between the two shear values immediately on either side of the support will equal the magnitude of the support load. Inspection of the shear force diagram will show that this is so.

 

We are noticing that the same input is giving us different results.  For example: We input data (soil types and properties, surcharges, depth of excavation, etc....) and the program gives us results (toe, bending, wale forces, etc.......). We then change our data to see what different results we get. That is fine but when we change back to the original data we will get different results than what was input before.  What's going on?

The soil K values have probably been modified inadvertently. Check  the K values before and after the changes - they must be the same if the same  results are to be found.   For example, load Demo2 and note P, waler load, toe, etc. Print the  Input/Output page. Open the Excavation page, and select a 20 degree slope -  P, etc all change. Now select level ground again - they change again, but do  not go back to what they were. Print the Input/Output page and compare the  soil K values with the previous page - they are different. This happens  because the K values are recalculated to their theoretical values, based on  phi, when slope or level ground is selected. However, the K values in the  Demo2 file do not agree with the theoretical values, calculated from phi  (they don't agree because they were set differently in the original source of  this example - see below). Similar things can happen when the pressure model  is changed.

To summarize: if toe, frame load, bending moment, etc change, then it's a  result of a different pressure graph. If the pressure appears to have  changed, then check the K values at each depth.   Email us if this does not solve the problem.

 

The steel piling have a limiting stress of 25 ksi for maximum bending moment.  The sheeting I am considering will allow more.  How can I change it?

The 25 ksi value was placed for conservatism.  You can change this value in the database for each individual section.

 

Can the active and passive soil properties be entered as separate layers?

No; all layers in SPW 911 are horizontal.

 

I am designing a wall with a sloping backfill. I have changed the water level. If I change the pressure method to, say, Coulomb and then back to Rankine, the pile length reduces significantly. What's going on?

The soil coefficients are changed when you switch from Rankine to Coulomb and back again. Each time you switch, the K values revert to their theoretical values under the selected model. The pile length used when you switch back to Rankine is because a different pressure is being calculated due to the changed soil coefficients.

 

How can I add different sections to the sheet pile database and not lose the information?

You need to "post" a change after making a new entry, by selecting another record or clicking the "tick" button on the navigation bar - see the Help file, under "Databases - Database editing" for more details.