Dear Sharmin! You ask questions, answers to which can only be given by a professional. The work you are doing is very responsible. If the construction is built in violation of the rules, it will collapse and people will die. Let me offer you general laws for the construction of such structures (annex).

http://environment.uwe.ac.uk/geocal/foundations/Fountype.htm

This simple and quick field test will give you a rough idea of bearing capacity of soil.

If this a project withing a class you are taking, you can refer to a reference. I recommend Das Book " Principles of Geotechnical Engineering". It is a good book to start with.

If this is a practice project, the bearing capacity should be estimated by a professional because there are many factors that can control the decision. 

Esteemed Sharmin, 

Greetings, 

For the rock, it is quite complicated more than the case of soil. You have to obtain, first of all, the rock mass classification such as RMR, Q, and GSI, to convert the intact rock properties to the mass properties. There are several empirical methods to determine the influence depth of the foundation loads into the soil, however, in the case of rock, it is more sophisticated due to the arching effect. For quick judgment on the bearing capacity for the preliminary stage, you may find some correlations based on the RQD of rocks and the unconfined compressive strength of the J. E. Bowles book. Nonetheless, such an empirical value should be verified through the rock mechanics theories and equations, for more details kindly have a look at Goodman book and Practical notes for Dr. Hoek. 

http://webapps.unitn.it/Biblioteca/it/Web/EngibankFile/296074.pdf

https://www.amazon.com/Introduction-Rock-Mechanics-Richard-Goodman/dp/0471812005

https://www.rocscience.com/documents/hoek/corner/Practical-Rock-Engineering-Full-Text.pdf

The calculation of bearing capacity will depend on the data you have: Geotechnical profile of the soil? Results of laboratory tests (for the different layers of the soil)? Results of in-situ tests?

After the calculation of the bearing capacity, the settlements must be verified.

Dear Sharmin,

As you can see, it is a very commited resposibility to design an actual foundation. As Prof. Ali told, if you are doing an academic project, the Das book is a good aproach (telling about soils) but for the complexity of rocks you mus survey or know the rock mass properties (RQD, Q and GSI).

But talking as a professional, if you pretend to estimate the bearing capacity, you must take into account much more informations, such as the topography, location of the biulding, nearby constructions and their foundations, construction procedure, rock failures and some many considerations (e.g. if you have to improve the underground conditions).

In the second case (professional project), my recomendation is to first of all contact a geologist to obtain a geological study and then work on the rest the project.

Regards.

I recommend you tro read the RED BOOK from BEngt FEllenius. Is free to download at:

http://www.fellenius.net/papers/370%20The%20Red%20Book%20-%20Basics%20of%20Foundation%20Design.pdf

And you are right, the concept of capacity is basically erroneous (understood as final load) unless you are calculating shaft resistance of piles with absolutely no toe resistance. All the concept should go via a deformation analysis and the allowable load should be a consequence of that