In this video, we are going to take a look on the different aspects of modeling and designing retaining walls in Autodesk Robot Structural Analysis.
(Great Discussion with our dear Subscriber Engr. Donald Khanye)
Questions:
1. The foundation “length” in the final RSA design is about 4.2 meters. Braja M Das proportioning dimensions guides for this length are 0.5 to 0.7H (1.5 to 2.1 meters). I am concerned that 4.2 meters does not “feel right, it feels too long” are you not worried about this dimension?

2. @ about 30h11 you explained the importance of the soil weight above the heel; @ about 26h30 aren’t the reactions of the wall support you mentioned not only representing the HORIZONTAL components of the soil above the heel and not the VERTICAL components?

I am thinking that maybe the VERTICAL component of the soil weight above the heel should be model into the design of the retaining wall foundation somehow? What are your views

CEE:
As for Q1, I totally agree. The reason why the retaining wall was this large is because of the bearing capacity. The loads on the foundation are eccentric, and cause higher pressure on the toe and even uplift in the heel region.

Robot suffers in not taking some points about the heel into account. I will address this issue in a more detailed video in the future. This is also point 2

for point 2:
The reactions you see on the foundation horizontal soil pressure and moment.
the vertical force you see here is due to the weight of the wall.
This is what I mean by "there is no full module that designs retaining walls in robot, and the engineer has to make it in two pieces"

However, you gave me an amazing idea, and I will post something about this next week after doing some research.
I am betting that one can define the soils weight above the heel in the geotechnical soil characteristics by putting the soil height on one side 3meters.

I still have - however - to check the accuracy of calculations. I will prepare a video about this.

Your question is amazing, and I will put it in the description
Regards,
CEE


Timestamps:
0:00 Introduction
1:05 Modeling
4:37 Defining Soil Loads
13:35 Calculations and Results
16:37 Design of Wall
19:36 Provided Reinforcement of Wall
21:07 Drawings and Calculation Note
24:01 Foundation Design
26:12 Design Options
28:45 Calculation and Results
32:41 Reinforcement Details and Drawings
34:21 Outro