The building
design is a very complex and scientific process due to higher required safety
for its residents so following procedures should be kept in mind during the
design of buildings, I am submitting an exemplary drawing to narrate every
procedure with visible references.
Need of Building and
Architectural Design.
Residential Building Plan (Fig no.1)
SIZING AND CAPACITY OF
BUILDING
The building
design is a very complex and scientific process due to higher required safety
for its residents so following procedures should be kept in mind during the
design of buildings.
Sizing of
rooms, Size of Doors & windows, Height of Building, Size of Overhead water
tank, Size of the Main gate, Size of sewer pipes, Size of Manholes, Size of
Septic tanks, Slope of Ramp in front of the main gate, Size of Porch, Size of
Bath Rooms, Size of Store, Location of Stairs, Number of Lights, Fans, Air
Conditioning, Number of Ventilators, Height of Parapet wall, Size of
Cantilevers, Size of Open to sky s. Size of Kitchen Cabinets, Kitchen Counters
and sizing of Kitchen Sinks, Location of Shower, water closets, Floor Traps,
Bib cocks, Hand Basins, Toilet Showers, Position of light plugs, Switch Boards,
Distribution boards, Size of Electric Cables, Size of Sewer pipes, Etc.
Design of Sub-Structure
and Super-Structure.
Design of
Sub-Structure.
Building
structures should be designed according to the availability of materials from
the local market because this is the main reason to control building costs.
The most
lower structure generally called foundation or Sub-structure should be designed
considering the bearing capacity of Ground-level where the foundation will be placed.
Normally it ranges from .5 Ton/Sft to 1.5 Ton/ Sft.
Let's say
after testing we availed Bearing Capacity 1Ton/Sft and now we have to design
our foundation structure considering BC of 1 Ton/Sft.
Take the
biggest square panel slab from a given plan that is Drawing room whose size is
(14'x14') where wall thickness is 9" having a good class of bricks, now we
will add one wall thickness in size of slab panel and our effective span will
be 14.75'x14.75'
Now we have
to do some simple calculations
Roughly Thickness
of slab for two-way slab panel = Effective Span/35 =14.75x12x1/35= 5" so
slab thickness will be 5 " for the entire slab.
Now the
width of foundation = (Weight of Structure) /(Wall Perimeter x Bearing Capacity)
Now we have
only the value of bearing capacity which is 1 Ton/Sft
Weight of
structure = Weight of Walls + Weight of
slabs +Weight of Foundation+ Imposed loads (Live Loads + Dead Loads)+ Load of
Finishing
Weight of
Walls = Perimeter of all walls x Height of walls x Thickness of walls x Density
of Brickwork
Note:-
Brickwork density = 120 Lbs/Cft
But in case
of solid block, walls density will be 140 Lbs/ Cft
Perimeter of
Walls = 50.75+50.75+30.75+30.75+30.75+30.75+4.75+10+4.75+11.75+14.75+10+5.75
=286.25 Rft (Dimensions are calculated from given plan)
Weight of
load bearing walls = (286.25x12x.75x120)
=309150 Pounds
Weight of
Load-bearing walls in Tons =309150/2240 = 138.01 Tons
Weight of
Slabs =Length x Width x Thickness of slab x Density of RCC
Dimensions
as per Fig no.1 = 50'x30'x5/12'x150 Lbs/Cft=93750 Lbs/2240= 41.85 Tons
Imposed loads
(Live Loads + Dead Loads) =40 Lbs /Sft
Total
Imposed Load = 50x30x40 PSF= 60000
LBS=60000/2240=26.78 Tons
Load of
Finishing= Weight of plaster +Weight of Roof Waterproofing
Weight of
Plaster =2 Times of perimeter of walls x Height x Thickness x Density
=2x286.25'x12x.06x50
Lbs/ Cft=20610 Pounds/2240=9.20 Tons
Weight of
Roof Water Proofing=50x30x 50 Psf=75000 Lbs/2240= 33.48 Tons
NOW putting
values in following Formula as also mentioned above
Weight of
structure = Weight of Walls + Weight of
slabs +Weight of Foundation+ Imposed loads (Live Loads + Dead Loads)+ Load of
Finishing
=(138.01
Tons+41.85 Tons+ 26.78 Tons+9.20 Tons+33.48 Tons) x 1.25 times= 311.65 Tons Say
312 Tons
Note 25 % of
total structure weight added for the weight of foundations
Factored
Load = 312 Tonx 1.5 Times = 468 Tons
Now width of
foundation = (Weight of Structure) /(Perimeter x Bearing Capacity)
To calculate
width of foundation putt values in the above formula
=468
/(286.25 x 1 )= 1.69 ft
We have
stepped footing in foundation so we can use 22.5" wide stepped layer in
Brick Work then 18 "then 13.5" wide and then 9" Bedding Concrete
of 30" wide may be laid under the brickwork.
1-We will
use section (b) for load-bearing walls as shown in the above figure adopting B=
30 inches c=3.75"
2-PCC
(1:3:6) The thickness of step 1- as
shown "B" = 30" and thickness "d"= 4"
3-Brick Work
(1:5) Width =22.5" Depth= 6"
4- Brick
Work (1:5) Width =18" Depth= 6"
5- Brick
Work (1:5) Width =13.5" Depth= 6"
6- Brick
Work (1:5) Width =9" Depth= Up to Roof slab bottom
7 -Depth of
Excavation = 22"
Section (a)
named as simple footing will be used for boundary wall having 9"
thickness.
Concluding
the above calculations I will narrate the foundation in the wording of
specifications as follows
1-
Excavation in all types of soils except rock and including lead of 50 ft and
lift of 4 ft for surplus soil, Average Size of excavation trench will be
(30"x22") complete in all aspects.
2-Provide
and Lay Pcc (1:3:6) 4" Thickness using Good class of cement, sand and
crush completely in all aspects.
3-Brick Work
(1:5) Using Good class of Bricks and cement sand mortar
4-DPC
(9" wide and 2" deep ) will be provided on FFL Using a (1:2:4) ratio
having three coats of hot bitumen and 2 layers of polythene sheet
Trenches
will be filled with surplus soil and will be compacted up to 100 % modified
proctor test and the lower area under flooring will be filled with sandy soils
and will be compacted layer by layer up to 100 % Modified Proctor value.
Design of
Super-Structure.
Super-structure
mainly includes load-bearing walls, Slabs, Lintel and beams, Overhead Water
tank, and Columns.
Design
justification of 9" thick walls is very simple here as the wall bears 50%
of brick strength and the brick strength for good bricks has been the standard
compressive value of 1800 PSI, It means we will use 900 PSI for or brick walls.
The top area
of all walls = Perimeter of walls x Width of walls
= 286.25
x.75 x144= 30915 Sq.Inch
The load-bearing capacity of walls = 30915 Sq.Inchx900=27823500 Pounds /2240 =12421 Ton x .33=4099 Ton (This is the overall bearable loading value of load-bearing walls whereas our total load is 468 Ton which is only 11.41 % of the total bearable load.
Design of
RCC Slab (1:2:4) 5" thick
Roughly
Thickness of slab for two-way slab panel = Effective Span/35 =14.75x12x1/35=
5" so slab thickness will be 5 " for the entire slab.
Now we will
formulate the following equation to find out the thickness of the slab and
required Steel spacing for the slab.
Moment of
Resistance= K.b.d1.d1
Where K is
factor value in Elastic Theory Design method
b= is taken
as 12 " which is constant for all slabs when adopting Foot Pound System.
d1=
Effective Depth
As we know
that MR (Moment of resistance) = Bending Moment
So Bending
Moment of square slabs =
wxlxlx12x1/16 --------------EQ.no A
w= 130 PSF
for residential buildings
l=14.75 ft
as effective span
so putting
values in EQ.no A
Bending
Moment= 130X14.75^2X12X1/16= 21212 lbs-in
Comparing MR (moment of resistance) = Bending Moment
K.b.d1.d1=21212
lbs-in
184X12Xd1^2=21212
lbs-in
d1= 3.04
inches say 3.5 " adding 2 concrete
covers of 0.75"+0.75"=5"
so overall
depth of slab is 5"
Now we will
calculate the area of steel
As= B.M/Fst
.la --------------Eq .no. B
La=.857d1
Fst =20000
Putting
values in Eq .no. B
As=21212
lbs-in/20,000x0.857x3.5" = 0.353 Sq.in of steel is needed in each foot of
slab.
Spacing of
bars using 1/2" dia bars =Area of 1/2" dia bar x 12 x1/As=
0.196 12
x1/0.353= 6.66 say1/2" dia bars @ 6.5 Inch Center /Center will be
used in both ways of 5" thick slab
having ratio of (1:2:4)Concrete.
use 50 % of
As in negative reinforcement so the area of negative reinforcement =
.50x0.353=0.1765
Sq.in
Using
3/8" dia bars ,spacing =0.11x12/.1765= 7.47 "
According to
British RCC code spacing should not be more than 1.75 times of Effective depth
(d1) of slab =so 3.5"x1.76= 6.125 say Use 3/8" dia bars @ 6 inch and
place holding bars % 12-inch center /center.
Note:-
Other slabs will be calculated with the same methodology or maybe roughly
calculated comparing other spans with the Larger span which is designed as above.
British Engineering design contains Load Factor and Elastic Theory Method which contains Factor of the safety of 3 Times.
Construction Procedure with all activities.
1- Leveling
of Ground Using Tractor with Blade.
2-Layout of
Building.
3-Excavation
in form of trenches.
4-Compaction in trenches.
5-Provide
and Lay PCC (1:3:6) in the trench using mixing machine and labor.
6-Provide
and Lay Brick Work(1:5) using Good Materials and Labor.
7-Vertical
DPC from Foundation Concrete to Finish Floor levels
8-Back
filling of trenches, Area under flooring, and 100 % modified proctor compaction
in layers not exceeding more than 6" thickness.
9-Provide
and Lay Horizontal DPC on all walls at Finish Floor Levels.
10-Provide
and lay PCC sub base for flooring except for washrooms and kitchens.
11-Provide
and Lay Brickwork and Lintels in Super Structure.
12-Scaffolding
and shuttering of Slab.
13-Steel
fixing in slabs and beams.
14-Supply
and Fixing of Electric conduits in Roof slab.
15-Pouring
of Rcc (1:2:4) Slab 5" thick.
16-Removal
of shuttering after curing time normally after 14 days because concrete reaches
up to 90 % of its strength and can support its own weight very easily but slab
should not be loaded within 28 days from pouring time.
17- Provide
and Lay Brick Work of Parapet wall
18-Supply
and Fixing of Electric Conduits and Boxes in walls including grooving and
placing of pipes in walls and finally filling of grooves with Mortar.
19- Supply
and Fixing of water Supply in walls including grooving and placing of pipes in
walls and finally filling of grooves with Mortar.
20-Provide
and Lay sewerage pipes at the inner and outer side of the building along with
the construction of Manholes and galley traps, and connection with main sewer
line complete in all aspects. The sewer line will include P-traps, Floor Traps,
bends, elbows, Unions, sockets as per requirements.
21-Plastering
of walls including fixing of Door and Window Frames.
22-Construction
of Boundary wall including Fixing of the main gate with concrete Pillars
complete in all aspects.
23-Construction
of Flooring including fixing of tiles on floors and fixing of tiles on bath
room's walls up to door heights.
24-Supply
and Fixing of Wooden cabinets, Doors, Windows (Aluminum made), Stair Railings
Etc.
25-Fixing of
Bath Accessory Set including Wc,s , Wash
Hand Basins or Vanities along with fixing of marble slabs, Showers, and Bib
Cocks.
26-Painting
of Doors, Grills, and railing.
27-Provide
and lay roof waterproofing along with the construction of overhead water tanks
and fixing of rainwater drain pipes.
28-Distemper
at inner walls and Weather shield at the outer side of walls with three coats
complete in all aspects.
29-Fixing of
Electric Accessories including Lights,Fans, Ac,s , Distribution boards, Earthling systems, Main
doorbell, Smoke detectors, Exhaust Fans, Complete in all aspects.
30-Construction
of Ramp for car porch in front of Main Gate.
31- False
Ceiling in Rooms
32-Construction of Floor beds including concrete work, Brick Work, Plastering and Supply, and laying of sweet soil for plantation.
Possibilities of Construction
Activities Quantities done by Manpower and Machines.
One Tractor
can Level 100 ft x 100 ft area with maximum volume of soil per day 5000 Cubic.
Feet.
Hourly
Fueling may be calculated with following formulas
Maximum
Hourly Fuel Consumption = Horse Power of Machine x 0.12=Liters
Minimum Hourly Fuel Consumption = Horse Power of Machine x 0.10=Liters
Surveyor is
Professional who is responsible for LayOut and Leveling process in
Construction Industries. Machines and tools used in Surveying are Leveling
Instruments, Theodolite, Total Station, Measuring Tapes, Etc.
In building
Construction One Surveyor Along with helper can easily Control process of
Layouts and Leveling in area of 15000 Sft /Day.
Shuttering for Pcc under the stepped footing of building
One
carpenter and Helper can do Shuttering to prepare the area of 150 Sft.
2 Masons
along with 15 Labors can do 1000 Cft.
For the construction of RCC slabs thickness from 5" to 7"
One
Carpenter and two labors can do 80 Sft of Shuttering in One day
One Steel
Fixing and one helper can do 500 Kgs of steel in 8 hours.
3 Masons
along with 18 Labors can do 800 Cft .in
8 hours using a mixing machine, Tower Lift in construction of slabs for single storied buildings.
Brick Work using cement-sand mortars.
One Mason
and 2 Helpers Can complete 70 Cft of brickwork in 8 hours, And Half day of 1
Carpenter and 1 Helper will be consumed to make formwork.
Cement Plaster.
One Mason
Along with 2 Labors Can complete 130 Sft of plaster And Half day of 1 Carpenter
and 1 Helper will be consumed to make formwork.
Tile Floors
One Mason
and 2 Labors can complete Fixing of tiles for the area of 100 Sft in 8 hours.
Distemper
One Painter
and 2 Labors can complete an Area of 450 Sft in 8 Hours With the Application of 3
coats.
Weather
Shield
One Painter
and 2 Labors can complete an Area of 400 Sft in 8 Hours With the Application of 3
coats.
Formwork
workers will be provided as per the height of the structure.
Wall Grooving and Water
Supply pipes
2 Plumber
and 2 Helpers can do grooving and water supply piping for 1 Wash Room /Day
Bath Accessories
2 Plumber and 2 Helpers can Complete 1 wash Room in 4 Days including all accessories of washroom.
1 Electrician and 1 Helper can
complete 20 Sft (Covered Area) in 8 Hours
Woodworks in Domestic buildings
1 carpenter
and 1 helper can complete 7 Sft in 8 Hours.
Above working
can be considered for the construction of residential buildings in ideal circumstances
as these are experienced observations and
practicable having small resources.
