Offset Dead Load Surcharge
Offset Dead Load Surcharge
(OP)
I am looking for a simple mathematical solution for magnitude of offset surcharge above CMU block wall. The wall above is also modular block wall about 1.2m(4.0ft) high. The lower wall is about 6.0ft high. The offset distance is about 6.0ft.between walls. Do i have to included Dead load surcharge from wall above? If i am designing the wall as gravity wall and if yes by how much magnitude. Is there any equation to calculate this type of Load Geometric configuration.
Thanks for suggestion in advance
Thanks for suggestion in advance





RE: Offset Dead Load Surcharge
RE: Offset Dead Load Surcharge
But what I am trying to design is a Multidepth gravity wall system. So within the space limitations I can achieve 2 things eliminate need for geogrid and hence additional excavation. Do just enough excavation for placing the blocks and reduce the width of block as I stack up due to lesser earth pressure from top. I am not sure what type of analysis I should do in order to take the load from the wall above and multidepth gravity wall model since I am designing a gravity wall I will only to external analysis. I tried to model this situation in MSEW software (for geogrid walls) applying a strip surcharge of upper wall from behind. I am wondering if there is any mathematical equation for stress distribution at depth to calculate the soil/ offset dead load surcharge
RE: Offset Dead Load Surcharge
RE: Offset Dead Load Surcharge
The NHI Segmental Retaining Wall manual (2nd Ed) does address this case (Refer to section 2.5.4 Tiered Walls), as was previously noted by Boondog. The diagram shown in the NHI manual shows straps however paragraph 2.5.4 addresses how to modify the method for gravity walls.
I have also seen that certain wall manufacturers use an approximatation technique that will effectively neglect the surcharge of the upper wall if the setback is greater than the lower wall height and the upper wall height is less than the lower wall height. Seemingly the wall geometry you have described would satisfy these requirements.