What Type of Footing or Foundation Will I Use?

You must provide the details of the site. Maybe you should just ask your instructor to provide details and drawings and see what he gives you.

Just adding to what lynlynch has said, you need a lot more information to design such a foundation. If I were designing the foundation, I would want the architect to supply conceptual drawings showing the plan layout and the depth of the basement or underground parkade if applicable.

I would then call a geotechnical firm to drill a number of test holes throughout the site and prepare a soil report. The soil report would contain logs showing the variation of soil types, the moisture content and blow count at various depths. It would contain a detailed description of the geology of the area. It would indicate areas of old fill.

Finally, the soil report would offer recommendations as to foundation type. If applicable, it would provide an allowable soil bearing value for shallow foundations, i.e. footings. It could offer an alternate using drilled piles or caissons and would provide the criteria to size those. Depending on what is found in the soil investigation and what type of equipment is available locally, driven steel or precast concrete piles could be suggested as options for the engineer to consider.

In your situation, you do not have all of this information, so you either have to get it from your instructor or make it up yourself. In the Philippines, you would have to consider seismic effects and possibly typhoons, both of which have an effect on the foundation of a fifteen storey building.

You should undertake to do the work yourself as best you can. If you run into difficulties, CR4 members would be pleased to offer suggestions, but please do not expect details and drawings from this or any other forum.

If this building is to be constructed on reclaimed land then a exhaustive Geotechnical study of the underlying soil mass needs to be undertaken of the condition there. This includes numerous soil borings being taken, sample of which will be bought back to the soils laboratory and tested and examined by a certified Geotechnical Engineer. This engineer will most likely issue a Geotechnical Engineering Report, also known as a Soils Report which will include recommendations for design and constructing a the building foundation system.

Of primary concern for a building being supported by a fill area is short-term and long-term soil consolidation (subsistence). In wet areas and landfill areas this can be substantial!

In your part of the world I'd be very worried about an earthquake event where the in-fill area liquefies and the foundation shakes like "Jello" and ultimately the foundation looses its support, thereby resulting in a catastrophic building collapse.

In this sort of scenario, I can envision that properly designed end bearing piles, either steel or precast concrete) be driven to bedrock below the fill area. Atop of a grouping of piles will rest a reinforced concrete pile cap. You can also construct cast-in-place caissons that extend down to the bedrock. Piles or caissons will resist the earthquake lateral forces and building resistance movements. The building columns and exterior bearing wall facade (if present) itself will rest on the pile caps. All of these structural foundation elements must be designed by a Licensed Structural Engineer.

Again, it is IMPERATIVE that a geotechnical study be performed or else you're asking for an ultimate collapse of the building, and will be eventually held and convicted in a court of law for gross incompetence etc. for any and all property damages and fatalities and injuries to the people effected by such a collapse. That is the real reality of the situation.

Good luck on your project!

thank you all for your suggestions il just stick with pile footings and study it. TY

you would need to have test results of the ground compaction before you can do any calculations. this is normally done by drilling test holes.