That was why I posted in the fist place, I felt my FS was too low. I was shooting for a min FS=1.5 for a safe design.
I am setting up a meeting with the contractor to look into different pit configurations, I agree with you PEinc, I do not think that the contractor's method is the best...
The contractor is using timber lagging with a steel waler and strut system for the pit. The concrete thrust block is actually located behind the jacking pit. He wants to construct the jacking pit, dig behind the pit and use the lagging to form the front face of the thrust block. I made the...
I have a similar project, 17' deep trench with (2) 300ton jacks (= 1,200 kip jacking force). The contractor wants to use lagging and not drive sheeting, so basically all I have is the concrete block to resist the force of the jacks. I checked the block by having a driving force of the jacks...
ahhh, details details, sorry about that, the trench varries from 5'to 20' deep and is pretty much set a 8' wide. Another thing to add in is that the water table is varies also.
thank you for the CA shoring manual that looks like a great starting point. I have to say the CA DOT always has...
the link I included shows the OSHA table and there loads are what I am basing my calcs off of. I even called OSHA about where they found there values, but they could not even find the table, not much help from them.
Does anyone have any tips on designing timber trench shoring. This should be easy, but I am missing something. The method of shoring the contractor has proposed is with vertical wood planking which are 3X8 or 4x6 douglas fir with a bending strength of 1500 psi. The system consistes of these...
