VARIOUS  ELEMENTS OF BUILDING

PCCFOOTINGCOLUMNSSSMPLINTH BEAM

PCCThe Plain cement

concrete consists of cement, sand and a coarse aggregate

mixed it in suitable proportions in

addition to water.

PCC IS MAINLY USED FOR FOLLOWING PURPOSES

It is used as a protective layer for the RCC above so that water from the RCC is not absorbed by the earth below. 

Provides a base for the concrete and also helps workers to set out the structure above in a easier way

Act as a cover to reinforced cement concrete i.e. Resist corrosion of steel bars in footings

Moisture available in soil should not absorbed by R.C.C footings which causes corrosion of reinforcement

0the aggregate size is 40mm down size0the concrete should be mixed in the

top & placed it where we want it may be machine mixed or manual

0The depth of PCC depends on SBC of soil

0In our site they provided 150mm thick cement concrete bed

0In the ratio of 1:4:8 i.e., 1 part of cement, 4 parts of fine aggregates and 8 parts of coarse aggregates by volume were used in it.

FOOTINGS

0Footings are pads or strips that support columns and spread their load directly to the soil.

0At our site, spread footing and one combined footing are provided

0Spread footing are provided to support an individual column, it is called isolated footing

0Depending on the size and configuration of the building, spread footers can be buried just below ground level or several feet below the surface

0This type of footer design is highly beneficial to builders and homeowners

0 This design helps to minimize cracks and other signs of damage that occur as a building settles over time

0There are 44 footings and dimension of 2400 x 2000 x 600mm0At our site we learnt how the centering

for footing been done. First applying oil and checking for all tight joints at the corners.

0Combined footing are provided when the two columns are so close to each other that their individual footings would overlap.

0 A combined footing is also provided when the property line is so close to one column that a spread footing would be eccentrically loaded when kept entirely within the property line. By combining it with that of an interior column, the load is evenly distributed.

0A combine footing may be rectangular or trapezoidal in plan.

0Trapezoidal footing is provided when the load on one of the columns is larger than the other column.

0The use of combined footings helps spread out the loads out to the adjacent footings in order to minimize stresses in the footings and reduce the differential settlement between them.

COMBINED FOOTING @ OUR SITE

COLUMN0Columns are vertical members that

support loads from the beam or slabs. They may be subjected to axial loads or moments

0In our site they provided rectangular and circular columns

0The sides of rectangular column varies from

230mm to 600mm.0The diameter of circular column is

450mm.

Starter for columns

SSM- SIZE STONE MASONARY0The SSM is a substructure is the lower

portion of the building, which transmits the load of the superstructure to the subsoil

0SSM distributes the loads of the super structure, to a larger area so that intensity of load at its base does not exceed the SBC of the subsoil

0SSM provide levelled and hard surface over which super structure can be built

0The stability of the building ,against sliding and overturning ,due to horizontal forces such as wind earthquake etc. Is increased due to SSM

0The ratio of cement mortar is 1:6 i.e., 1 part of cement and 6 parts of fine aggregates(sand)

0Stepped SSM are provided in our site.0In our site undressed stones are used.0The grade of concrete used in SSM is M100In SSM as per code(IS1597 PART 1:1992) we

have to provide break @every 1m or 2m

IN OUR SITE THEY PROVIDED BREAK FOR EVERY 1m

PLINTH BEAM0It's the sheer wall load that needs to be

transferred to the foundation; as such, 4” thick plinth concrete is adequate

0In RCC frame structure, plinth acts as a tie, as a beam at ground level itself. More recently, after few disasters we have faced, RCC plinth beams are being recommended for their earthquake-resistant properties.

0In our site they used plinth beam of size 230 x 530mm

PLINTH BEAM UNDER CONSTRUCTION