How to construct roof?

WHAT IS FOUNDATION  ?

It is the engineering field of study which is applied  to the design of those structures which support other structures, most typically buildings, bridges or transportation infrastructure. It is at the periphery of Civil, Structural and Geotechnical Engineering disciplines and has distinct focus on soil-structure interaction.

It is also called as ground sill, which transfers loads to the ground. It is generally categorized into two types i.e

        1.Shallow foundation             2.Deep foundation

1.SHALLOW FOUNDATION:- A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths as does a deep foundation.

   

2.DEEP FOUNDATION:- A deep foundation is a type of foundation which transfers building loads to the earth farther down from the surface than a shallow foundation does, to a subsurface layer or a range of depth.

STEPS FOR A FOUNDATION WORK:
1.SURVEY WORK-This step is generally completed by a professional surveyor to determine the appropriate distances from the property lines. This ensures that the building will start out correctly and to code. The corners of the building will be marked using surveyor’s stakes. Then the surveyor will place offset stakes about two feet out from the surveyor’s stakes. The digging for the foundation will be done using the offset stakes as the guides. This allows for extra room so the exterior foundation walls can be worked on.

2.EXCAVATION-A structural engineer will determine the depth of the excavation. All surface soil needs to be removed to expose the soil that is compacted enough to bear the weight of the building. The depth will vary per building. The top of the footing must be below the frost line as this prevents the concrete from cracking when the freeze-thaw cycle occurs in the soil surrounding the building.

3.FOOTING-A footing is a poured concrete pathway that is used to spread the weight of the building from the foundation walls to the soil. They are wider than the foundation walls that they are supporting and form the perimeter of the building. In some instances, there are additional footings added inside the perimeter to support load-bearing walls.

4.DRAINAGE SYSTEM-Subsurface water is moved away from the foundation to prevent pooling water or flooding. The foundation drainage tile is made up of an uninterrupted run of punched drainage pipes that have been embedded in gravel along the foundation of the building. 

5.SUBSLAB-Generally, plumbing lines are run from the street to the building’s basement by going over or even under the footing. This is even the case for buildings that have their own individual sewage facility or drain field. These lines are covered with a poured concrete slab.

6.SLAB-A three to four inch thick concrete slab is poured between the foundation walls. This will help stabilize the base of the walls.

7.WALL-Foundation walls are poured concrete. They are poured using sets of forms that support the freshly poured concrete along with the appropriate bracings and hardware. Once the concrete walls are set and have achieved full strength, the form work is then removed.The engineer will determine the thickness of the wall by calculating the height of the wall and the load that the wall has to bear.

8.WATERPROOFING-A waterproofing sealant is applied to all of the exterior foundation walls that are below-grade. This is why the excavation of the foundation left room beyond the perimeter of the actual foundation. The sealant helps to stop water from coming in through the walls and into the building’s basement.

9.BACKFILL SOIL-Once the foundation is completed and the waterproofing seal is dry, backfill is pushed into the trenches around the foundation walls on the exterior. Some will backfill a third of the way with gravel and then top it will soil that drains easily. Backfill provides higher stability to the building’s foundation.

CEMENT USED FOR FOUNDATION WORK;-

(a) 33Grade cement---> used for plastering the walls

(b) 43Grade cement--->used for laying the foundation,to build the compound wall,for plastering,

(c) 53Grade cement--->mainly used for high raised building