Ground bearing slab - Traditional Approach for Bearing Capacity?

[SLaryea]

Hi Esteemed members

May be basic for some but I am looking to determine allowable/safe bearing capacity for a material that will be subject uniform load from a slab at grade.

Is it wise to approach this assuming say its a large pad/strip and apply conventional bearing capacity theories.

Thank you for reading

 

[Ron]

I notice you're in Great Britain...you probably have a minimum prescriptive code requirement for bearing capacity. In the US it is often 2ksf (96kPa).
For analysis, yes, a conventional approach is fine.

 

[EireChch]

A large pad will likely have a bearing capacity (shear failure) of several hundred Kpa is placed even on moderate ground.

Allowable bearing pressure (based on a max settlement limit) is your dictating consideration.

 

[SLaryea]

Thanks for this both.

I am only just starting to speak the lingo.

Eirechch - are you a basically saying the same as Ron I.e the first paragraph?

 

[EireChch]

No, RON is discussing codes which provide guidance on typical (or maybe minimum) bearing pressures based on shear for different material.

I am saying that in most cases, the bearing pressure is typically limited to that of which gives you your max settlement criteria.

For example, you could have a 2 x 2m wide, 0.5m deep foundation which has an allowable bearing capacity (i.e. shear failure) of 300kPa.

However, if 25mm settlement is your max settlement limit. Say you place 220kPa on your foundation, and it settles 24mm, then this is the maximum pressure you can apply to the foundation.

The 300kPa allowable bearing capacity (based on shear) is irrelevant as your settlement bearing pressure of 220kPa is dictating things.