Trench Excavation Shoring.

[Daca02]

Looking for input on a timber trench excavation shoring.

The trench is up to 12' deep and 5' wide. The soil is "type B" and is mostly sand. The site is to be dewatered during excavation.

The vertical and horizontal spacing is 4' between cross braces. All material is lumber.

My calculations show the 3x10 horizontal lagging, 3x10 uprights and 6x6 braces should be OK. From what research I've done online most lumber shoring use upright planks for the "sheathing" or a soldier pile and horizontal lagging design.

See attached image for reference.

 

[oldestguy]

Assuming you are asking for a check on design adequacy, well this site is not to be used for design as I understand it and using any design verification from here may well not be of value in case of some failure on the job. I'd opt for a commercially made trench shield.

 

[dik]

OG:
In these environs, trench boxes would normally be used. In particular if 12' deep.

Dik

 

[PEinc]

daca02, you can check your timber trench shoring design with information in OSHA's trench safety manual.

http://www.PeirceEngineering.com

 

[DDBPE]

Agree with Dik, it would be much safer and easier to go with a trench shield/box. Typically they are 8' tall and can vary in width and length. The reason for the 8' typical height is for transporting without an over-width permit. They are easily rented for short term and come with the required engineering certifications. For your case we would get the 8' tall shield and then slope the top 4 feet. Also, as PEinc pointed out, OSHA has a good section on trench shoring, which would be the governing safety agency.

 

[PEinc]

If the trench has a number of relatively closely spaced crossing utilities, a trench box may not be suitable. In that case, vertical timber shoring might be a better shoring method.

http://www.PeirceEngineering.com

 

[chicopee]

If I remember correctly you can stack one trench box on top of the bottom one, however, double check on my statement as regulations may have changed.