Restrained shoring system specifications 1

[route166]

I'm working on a shoring system with a waler and raker and am looking for specifications on how much deflection is allowed in the components.
Would l/240 be a good assumption?

 

[Bagman2524]

Deflection is a servicability concern. If the shoring system is just supporting your structure you just need to make sure it's strong enough.

 

[PUEngineer]

I wouldn't be so quick to say that deflections in a shoring system are serviceability issues. Deflections of certain components will affect the soil forces that mobilize. That would probably be something that your geotechnical consultant could help with. Beside that issue, your question seems a little ill-defined for an appropriate answer.

 

[route166]

I'll try to better define my question for an appropriate answer.

Is there a governing code for temporary work like a restrained shoring system for earthwork? Would it be the International Code Council?

What does the code say with regard to deflections of walers in such a system?

 

[dcarr82775]

I don't think there is any 'Code' deflection limit on shoring systems. FHWA has various documents and there is the old NAVFAC design manuals that give recommended guidelines. I am not sure if AASHTO gives hard limits or not. It really depends on why you are digging the hole, what goes in the hole, and what is above the shoring.

If there is a building on shallow spread footings directly above the shoring you want to design for at-rest pressures so you need a stiff structure. If you have a shoring system that will be part of a one sided form you will need to coordinate with the EOR of the building to make sure your shoring deflections will not eat up too much of their wall thickness. If you have a hole with some extra space inside you can live with some sizeable deflections that will some with getting members right up to their design limits. It is up to you to decide if your shoring deformations are acceptable.

 

[PEinc]

I agree with dcarr82775. Good answer.

http://www.PeirceEngineering.com

 

[CANPRO]

I agree with what dcarr has to say, but I disagree that there are no code defined limits for deflection in shoring. I don't have the code infront of me but I'm fairly certain that the CSA code (Canadian Code) governing formwork has defined limits.

In addition to any limits within a formwork code, your governing code for the concrete design/placement should have allowable tolerances for the finished concrete that would be obvioulsy be affected by excess deflection in the formwork.

 

[route166]

it's an earth retaining system, not shoring for a concrete floor.