bridge_engineer1
Structural
- Feb 13, 2023
- 1
Hi,
For abutment & retaining wall design AASHTO requires a live load surcharge.
My question is, is this load applied to the back face of the wall horizontally (ie no vertical component) or is the soil pressure applied at at angle due to angle of the wall and the soil-wall friction angle (like the soil pressure EH load is when using the Coulomb method)?
The equation in AASHTO for LL surcharge pressure is k * density * heq, where h equivalent is an equivalent height of soil for vehicular load, density is based on soil density and k is either at-rest or active depending on the wall flexibility. Since ka is based on coulomb earth pressure, which takes into account wall friction angle and wall angle, I usually assume the live load surcharge acts at an angle from horizontal equal to the wall friction angle and wall angle. I'm second guessing that because I found an example online that just applies it horizontally.
Thanks!
For abutment & retaining wall design AASHTO requires a live load surcharge.
My question is, is this load applied to the back face of the wall horizontally (ie no vertical component) or is the soil pressure applied at at angle due to angle of the wall and the soil-wall friction angle (like the soil pressure EH load is when using the Coulomb method)?
The equation in AASHTO for LL surcharge pressure is k * density * heq, where h equivalent is an equivalent height of soil for vehicular load, density is based on soil density and k is either at-rest or active depending on the wall flexibility. Since ka is based on coulomb earth pressure, which takes into account wall friction angle and wall angle, I usually assume the live load surcharge acts at an angle from horizontal equal to the wall friction angle and wall angle. I'm second guessing that because I found an example online that just applies it horizontally.
Thanks!