Foundations on sloping sites.

Sunday, December 5, 2010

The natural surface of ground is rarely level to the extent that there may be an appreciable slope either across or along or both across and along the site of most buildings.

On sloping sites an initial decision to be made is whether the ground floor is to be above ground at the highest point or partly sunk below ground as illustrated in Fig. 15.

Where the ground floor is to be at or just above ground level at the highest point, it is necessary to import some dry fill material such as broken brick or concrete hardcore to raise the level of the oversite concrete and floor. This fill will be placed, spread and consolidated up to the external wall once it has been built. 

Fig. 15 Fill an cut and fill.

The consolidated fill will impose some horizontal pressure on the wall. To make sure that the stability of the wall is adequate to withstand this lateral pressure it is recommended practice that the thickness of the wall should be at least a quarter of the height of the fill bearing on it as illustrated in Fig. 16. The thickness of a cavity wall is taken as the combined thickness of the two leaves unless the cavity is filed with concrete when the overall thickness is taken.

To reduce the amount of fill necessary under solid floors on sloping sites a system of cut and fill may be used as illustrated in Fig. 15. The disadvantage of this arrangement is that the ground floor is below ground level at the highest point and it is necessary to form an excavated dry area to collect and drain surface water that would otherwise run up to the wall and cause problems of dampness.

To economise in excavation and foundation walling on sloping sites where the subsoil, such as gravel and sand, is compact it is practice to use a stepped foundation as illustrated in Fig. 17, which contrasts diagrammatically the reduction in excavation and foundation walling of a level and a stepped foundation.

Figure 18 is an illustration of the stepped foundation for a small building on a sloping site where the subsoil is reasonably compact near the surface and will not be affected by volume changes. The foundation is stepped up the slope to minimise excavation and walling below ground. The foundation is stepped so that each step is no higher than the thickness of the concrete foundation and the foundation at the higher level overlaps the lower foundation by at least 300 mm. 

Fig. 16 Solid filling.

The load bearing walls are raised and the foundation trenches around the walls backfilled with selected soil from the excavation. The concrete oversite and solid ground floor may be cast on granular fill no more than 600 mm deep or cast or placed as a suspended reinforced concrete slab. The drains shown at the back of the trench fill are laid to collect and drain water to the sides of the building. 

Fig. 17 Foundation on sloping site.


Fig. 18 Stepped foundation.

Related Posts by Category:




22 comentarios:

Unknown said...

I'm thinking about getting my contractor to come up with a design for adding onto our kitchen. We're going to get this add-on started as soon as we talk to a professional. I'm so excited to get this building constructed!
http://www.lugbillconstruction.com/about-us

slv said...

I have a house on a hill and the structural engineer designed a slopping foundation and not stepped, is that ok?

Sharon Smith said...

Awesome useful post ! this page is about fishing. to get fishing trips , click on the link. Thanks !

Hi. Have you ever tried granite worktops aberdeen - thehomexpert.uk? ;)

Unknown said...
This comment has been removed by the author.
Unknown said...

You really ought to check out the granite worktops in aberdeen, just as Marcelina said.

Unknown said...

Its a huge mistake!

Unknown said...

We are going to build a long building (200m) and ground slop is 1.25%. Is it ok to construct the building according to slope of ground? Or it should be stepped.

Unknown said...

An impactful article indeed..
I'm grateful

Muy buenos Tipos de cimentaciĆ³n y descripciones

huzaifashaikh said...

Pretty good post. I just stumbled upon your blog and wanted to say that I have really enjoyed reading your blog posts. Any way I'll be subscribing to your feed and I hope you post again soon. Big thanks for the useful info. Badger Trench Box

Unknown said...

The information is very useful and enlightening to people that have building project especially on
a sloppy ground !

KASHAF said...

Seawall repair Miami Thanks for taking the time to discuss this, I feel strongly about it and love learning more on this topic. If possible, as you gain expertise, would you mind updating your blog with extra information? It is extremely helpful for me.

Unknown said...

The depth of foundation differs, is it okay to have varying depth of foundation based on slope of land

Adi shaikh said...

Badger Trench Box I think this is an informative post and it is very useful and knowledgeable. therefore, I would like to thank you for the efforts you have made in writing this article.

Hadi shaikh said...

how to repair a house foundation I think this is an informative post and it is very useful and knowledgeable. therefore, I would like to thank you for the efforts you have made in writing this article.

mexwell said...

Wow, cool post. I'd like to write like this too - taking time and real hard work to make a great article... but I put things off too much and never seem to get started. Thanks though. trench shoring systems

excavation for house foundation you can carry out by getting the help of Allsite Developments Pty Ltd. We do what you deserve.
hire excavator attachments

excavation for house foundation you can carry out by getting the help of Allsite Developments Pty Ltd. We do what you deserve.Our teams are fully licensed and certified. We do excavation with safety rules and regulations.

At Allsite Developments Pty Ltd, we have a huge scope of earthmover connections. hire excavator attachments from us at cutthroat costs.
Allsite Developments Pty Ltd has numerous backhoes and different extras for some site improvement undertakings. Along these lines, employ tractor connections to improve your work. At our place, we have immense scopes of plants, instruments, gear and apparatus. You can make it accord to your requirements.

EzhilGeetha said...

Your blog is very useful. You shared civil construction-related information. If anybody wants to build your building with your plan, they must engage one building construction. You give tips for civil construction. Building contractors in Trichy also shared building construction information.

kushwaha said...

This blog is very useful. Your blog is explain about civil construction information. Building contractors in Hyderabad also shared building contractors related information.

Post a Comment

 
 
 

Labels