Arching effect of soil between vertical braces
Arching effect of soil between vertical braces
(OP)
How do you account for the arching effect of relatively stable (OSHA - Type B) soils between vertical braces in a shallow (less than 8' deep) braced cut with vertical braces spaced from 4' to 8' apart?





RE: Arching effect of soil between vertical braces
While leave the sides open and expose the works to falling objects from the side? Place a piece of sheet steel on teh back sid eof the vertical braces and you have no problem.
RE: Arching effect of soil between vertical braces
RE: Arching effect of soil between vertical braces
The project geotechnical engineer should be able to design the system or provide the loads.
If you provide more information about the nature of the project, we may be able to help.
RE: Arching effect of soil between vertical braces
The shoring system consisted of 2" by 6" maple heart vertical uprights with two ea 2" by 6" maple heart spreaders in a 7.5 foot deep trench. The bracing (sets) were spaced 4 feet apart along the tench.
The active earth pressure can be calculated using a number of methods including OSHA's. Cohesive soil has some ability to "arch" between supports, thus I am trying to develop some rational for applying a percentage of the total load between supports to each support. Any input would be appreciated.
RE: Arching effect of soil between vertical braces
There may be other articles that can lead you to an answer but if you have Tezaghi's "Theoretical Soil Mechanics" you can review arching and detremine lateral pressure which would be smaller than if you use an active coefficient of 1. Roughly you would probably be one third of the value computed. This would take care of the arching effect. However, you need to review the concept. Hope this helps.
You may also finf some info on this subject in other texts
RE: Arching effect of soil between vertical braces
If you are trying to say that the arching means that you only have to consider a 2 or 3 foot contributing error, I think you are out of luck.
If OSHA's point is that sheeting should have been installed between braces, then your only argument is that the cohesion was enough to hold the surface, and again you are probabily out of luck.
RE: Arching effect of soil between vertical braces