24-07-2012, 01:00 PM
BUILDING CONSTRUCTION
FOUNDATION.pptx (Size: 209.75 KB / Downloads: 141)
INTRODUCTION
Every structure consist of the following two parts
1.sub structures or foundation.
2.superstuctures.
Generally sub structure is lower part of the structure, which is in direct contact with the sub soil and which transmits the loads of the structure to the sub soil is known as foundation or substructure.
Super structure is the part the structure which is above the ground level.
Requirements of good foundation
The foundations shall be constructed to sustain the dead and imposed loads and to transmit these to the sub-soil in such away that pressure on an it will not course settlement which would impair the stability of the building or adjoining structures.
Foundations base should be rigid so that differential settlements are minimized, specially for the case when super-imposed loads are not evenly distributed.
Foundations should betaken sufficiently deep to guard the building against damage or distress coursed by swelling or shrinkage of the sub-soil.
Foundations should be so located that its performance may not be affected due to any unexpected future influence.
SITE EXPLORATION
The object of site exploration is to provide reliable specific and detailed information about the soil and ground water conditions of the site which may be required for a safe and economic design of foundations.
Methods of site exploration, they may be grouped as follows
1.Open excavation
2.Boarings
3.Subsurface soundings
4. Geo physical methods
BEARING CAPACITY OF THE SOIL
A foundation should be designed to satisfy two essential conditions
1.It must have some specified safety against ultimate failure.
2.Settlements under working loads should not exceed the allowable limits for the super structure.
The bearing capacity of the soil used for the design of foundation is determined on the basis of above two criteria's.