Ground Bearing Slabs on Fill

[engstructural]

We often used a guide set by the local authority and housing building association of changing to suspended slabs in a house when there is over 600mm Dp. of fill material.

I am now looking at a large factory building and will have aprox: 600mm - 1500mm of fill below the floor. I am considering using a ground bearing slab but producing a spec. for the quality and compaction required for the imported granular fill. Can any one advise where I can get detailed info on this for the UK?

 

[Ron]

I'm not familiar with specific British standards, but I know that they are similar to US standards for many things.

First look at your soil conditions and the type of fill material you want to use. You will use select structural fill, it should be granular, and should not contain more than 10 percent passing a 0.074mm sieve.

Next, the soil should be placed in loose layers that do not exceed 300mm, each. Compact the soil to at least 95 percent of the maximum dry density determined through an acceptable moisture-density relationship standard used for your soils in your area. Here, we specify at 95% of the Modified Proctor maximum dry density.

Place and compact each succeeding layer until you have achieved the fill that you need.

Look for British Standard BS 1377-4 on the compaction testing, both field and laboratory.

 

[BigH]

There is no reason you can't put a slab on fill IF the fill is engineered and constructed correctly. Typically for structural fill we would use road subbase type material as a minimum although I have seen well graded sand used successfully. Many engineered fills are much better than the ground on which they are placed (or replace). Of more interest given an engineered fill is the ground on which the fill is sitting.

 

[oneintheeye]

dot specs for highway works is good ref.

 

[Ron]

herewegothen...not good to use DOT specs for a building. Different reference standards and procedures. Can get you into a "standard of care" breach issue.

 

[dik]

and you can proofroll it.