Appendix F: Complex Composite Structures

How to Design a Complex Composite Structure

Any cross section can be analyzed as a Complex Composite Structure. In order to analyze a Complex Composite Structure a user must:

Select the section that will be a Complex Composite Structure while in the Section Design Screen.

The next step is to modify the section so that it is not a typical design section. This will cause the program to start evaluating that section as a Complex Composite Structure. This can be achieved using any one of the following methods.

1. Gravity wall above geogrid reinforced soil mass
   1. Simple Gravity Wall
   2. Double Block Gravity Wall
   3. Fieldstone Long Anchoring Units (LAU) Gravity Wall
2. Two Different Reinforced Masses
   1. Longer Grid on Top
   2. Double Block Gravity Wall
   3. Shorter Grid on Top
3. No Fines Concrete (NFC) and Geogrid Reinforced Soil Mass
   1. NFC above Grid Below
   2. NFC Bottom Grid Above
   3. NFC Bottom Gravity Wall Above
4. No Fines Concrete with Two Different Mass Depths

Method 1

1. Gravity wall above geogrid reinforced soil mass
   1. Simple Gravity Wall
      1. Use the Edit Spacing button to start removing layers of geogrid at the top of the wall.
      2. This is done by clicking on the Edit Spacing button.
      3. Then by clicking the individual courses in the internal results table to modify the geogrid configuration.
      4. This causes the program to analyze the top of the wall as a simple gravity wall above a geogrid reinforced soil mass.
      
      
      
      
      
   2. Double Block Gravity Wall
      1. After the composite mass is created from (a) click the Double Block button.
      2. Click the individual courses in the internal results table to modify the blocks from Short Anchoring Units (SAU) to a LAU gravity wall.
      
      
      
      
      
   3. Fieldstone Long Anchoring Units (LAU) Gravity Wall
      1. After the composite mass is created from (a) click the Double Block button.
      2. Click the individual courses in the internal results table to modify the blocks from Short Anchoring Units (SAU) to a LAU gravity wall.
      
      
      
      
      

Method 2

2. Two Different Reinforced Masses
   1. Longer Grid on Top
      1. Edit two or more consecutive geogrid layer lengths at the top of the wall to be longer than the layers below them.
      2. This is done by clicking on the Edit Length button.
      3. Then clicking the individual courses in the internal results table to modify the individual geogrid lengths.
      4. When editing the length for the second geogrid check the “Allow this section to become a Complex Composite Structure”.
      
      
      
      
      
   2. Shorter Grid on Top
      1. Edit two or more consecutive geogrid layer lengths at the top of the wall to be shorter than the layers below them.
      2. This is done by clicking on the Edit Length button
      3. Then clicking the individual courses in the internal results table to modify the individual geogrid lengths.
      4. When editing the length for the second geogrid check the “Allow this section to become a Complex Composite Structure”
      
      
      
      
      

Method 3

3. No Fines Concrete (NFC) and Geogrid Reinforced Soil Mass
   1. NFC above, Grid Below
      1. Use the NFC / Gravity button to use either No Fines Concrete for a portion of the cross section
      2. This is done by clicking on the NFC / Gravity button
      3. Then clicking the course in the internal results table where the two structures will differentiate.
         
         
         
         
      4. This will bring a pop up window where the user can select whether they want a No-Fines Concrete structure on top and a geogrid reinforced soil mass structure below and specify a depth to the No-Fines structure.
         
         
         
         
   2. NFC Bottom Grid Above
      1. Use the NFC / Gravity button to use either No Fines Concrete for a portion of the cross section.
      2. This is done by clicking on the NFC / Gravity button
      3. Then clicking the course in the internal results table where the two structures will differentiate.
         
         
         
         
      4. This will bring a pop up window where the user can select whether they want a No Fines Concrete structure on the bottom and a geogrid reinforced soil mass structure above and specify a depth to the No-Fines structure.
         
         
         
         
   3. NFC bottom Gravity Wall Above
      1. Use the NFC / Gravity button to use either No Fines Concrete for a portion of the cross section.
      2. This is done by clicking on the NFC / Gravity button
      3. Then clicking the course in the internal results table where the two structures will differentiate.
         
         
         
         
      4. This will bring a pop up window where the user can select whether they want a No Fines Concrete structure on the bottom and a gravity wall structure above and specify a depth to the No-Fines structure
         
         
         
         
      5. For the case of a gravity wall above a No Fines mass below, once again the user has the option to select either a Double Block gravity wall or a Long Anchoring Unit (LAU) if using the AB Fieldstone product as explained in Method 1 above.

Method 4

4. No Fines Concrete (NFC) and Geogrid Reinforced Soil Mass
   1. This type of structure can be achieved by starting with a full No Fines Concrete design using the following steps.
      1. Start by clicking on the Design Parameters button in the lower left corner of the screen.
      2. Then select the Design Options Tab.
      3. Select the Design with No Fines Concrete to Yes and specify a depth for the No Fines Concrete mass.
         
         
         
         
      4. After clicking Hide click the Calculate button. Initially the section will be designed as a standard No Fines Concrete mass.
      5. To finish the design as a Complex Composite NFC Structure click the NFC / Gravity button and then select the structure configuration as shown in Method 3.