This document provides details on the design of a partial magnetic repulsion foundation building using U-Boots and autoclaved aerated concrete bricks. It includes an introduction to U-Boots and their advantages in foundation design. The manufacturing process of autoclaved aerated concrete bricks is described and they are compared to traditional clay bricks. The design of slabs, foundations, columns, and brickwork are detailed. Magnetic repulsion technique is discussed as a method to transfer loads from the structure to the raft foundation using different types of magnets.

1. INDIRA INSTITUTE OF
TECHNOLOGY MARKAPURAM
DEPARTMENT OF CIVIL
ENGINEERING

2. A PROJECT REPORT ON
DESIGN OF PARTIAL MAGNETIC REPULSION
FOUNDATION BUILDING BY USING U-BOOTS
AND AUTOCLAVED AERATED CONCRETE
BRICKS
• BY
• P SHIVASHANKER
• 167Z1D8719
UNDER THE GUIDENCE OF D.THRIMURTHINAIK ASSISTANT
PROFESSOR IN THE DEPARTMENT OF CIVIL ENGINEERING

3. CONTENTS
U-BOOTS
• Introduction
• Why we go for u boot
• What is U Boot
Technology
• Accessories
• Dimension
• Installation
• Advantages
• Applications
• Existence
AAC BRICKS
• INTRODUCTION.
• CHARACTERSTICS OF
AAC BRICKS.
• MANUFACTURING
PROCESS.
• COMPARISON BETWEEN
AAC BRICKS & CLAY
BRICKS.

4. CONTENTS
•DESIGN OF SLABS
•DESIGN OF RAFT FOUNDATION
•DESIGN OF COLUMNS
•ESTIMATION OF BRICK WORK
•MAGNETIC REPULSION TECHNIC

5. AAC BRICKS
•INTRODUCTION
• AUTOCLAVED AERATED CONCRETE (AAC) Brick was first invented in
mid- 1923 in Sweden by a Sweden Architect Dr. Johan Errikson. It is
also known as Autoclaved Cellular Concrete (ACC) bricks or
Autoclaved Lightweight Concrete (ALC) bricks and, autoclaved
aerated concrete bricks (AAC).
• These AAC bricks are made with a mixture of cement, fly ash, lime,
aeration agents and water involving an aeration process that gives it
the unique cellular structure.

6. U-BOOT INTRODUCTION
In 2001 an Italian engineer, Roberto Il Grande, developed and
patented a new system of hollow formers, in order to decrease the
transportation costs (and CO2 production).
The U-Boot formwork is a modular element made of re-cycled
plastic for use in building lighter structures in reinforced concrete
cast at the work-site
U-boot earliest projects were executed in 2002

7. WHY WE GO FOR U-BOOT
ONE OF THE OBSTACLES WITH CONCRETE
CONSTRUCTIONS, IN CASE OF HORIZONTAL SLABS, IS THE
HIGH WEIGHT, WHICH LIMITS THE SPAN.
FOR THIS REASON MAJOR DEVELOPMENTS OF REINFORCED
CONCRETE HAVE FOCUSED ON ENHANCING THE SPAN.
IN U BOOT TECHNOLOGY, SLABS ARE CREATED WITH LARGE
SPAN AND MAKES FLOORS THINNER BY REDUCING THE WEIGHT WHILE
MAINTAINING THE PERFORMANCE OF REINFORCED CONCRETE SLABS.

8. WHAT IS U-BOOT TECHNOLOGY
• U-boot beton is a formwork made of recycled polypropylene.
• Void form work placed in between the top and bottom
reinforcements of slab.

9. ACCESSORIES
• Connection bridge Spacer joint Closing
plate

10. GENERAL DIMENTIONS
• U-boot beton normally 52cmX52cm and Usually 10 ,13, 16, 20, 24
,28 cm in height.

11. INSTALLATION INVOLVES IN 4 STAGES
• PLACING THE LOWER
REINFORCEMENT
• On the form work the normal flat
reinforcement is provided
• In this reinforcement design is
based on the two way slab

12. PLACING THE U BOOT
BETON
• The u-boot is placed in the as per design
• The shells having a corner needles for
support the shell
• All shells are inter connected to steel rods
• In the steel rods look like a screws

13. PLACING OF UPPER
REINFORCEMENT
• In the triangular reinforcement
is provided for the purpose of
work as the beam
• Bottom horizontal rod is
connected to the flat slab
reinforcement
• The top corner is connected to
the shells connecting rods

14. PLACING OF CONCRETE
• Concrete is laid 20% of the
thickness of the slab to bind
the concrete with shell needle
• After filling concrete to the
full depth it is well
compacted

15. ADVANTAGES
1. Increased number of floors
2. Large span
3. Reduced slab thickness
4. No beams between columns
5. Reduction in the number of columns
6. Reduction in the overall load of the structure
weighing on the pillars and the foundation
7. Reduced foundations – less deep foundation
excavation
8. Improved acoustic behavior
9.Economic

16. APPLICATIONS
• Used in public buildings, hospitals, industries etc.
• Used in raft foundations
• Used in two way slabs

17. CHARACTERISTICS OF AAC BLOCKS
• Light weight
• Fire resistance
• Sound insulation
• Thermal insulation
• Strength and durability
• Perfect finish and dimensional stability
• Consistence and quality

18. MANUFACTURING PROCESS
AAC blocks manufacturing process starts with raw material
preparation. List of raw materials and relevant details are
mentioned below:
• Fly ash
• Limestone powder
• Cement
• Gypsum
• Aluminum powder
• Dosing and mixing
• Casting and curing
• De molding and cutting

19. COMPARISION OF AAC AND CLAY BRICKS
S No Parameter AAC Block Brick
1 size (L x H x B) 0.6m x 0.2m x 0.15m 0.23m x0.075m x0.115m
2 compressive
strength
3.72 n/mm2 (As per IS.:21851) 2.45 n/mm2
3 density wet 6.07 kn/m3 19.11 Kn/m3
4 density dry 7.84 Kn/m3 23.03 Kn/m3
5 fire Resistance 2 to 6 Hours depends on thickness 2 Hours
6 sound reduction in
Db
45 per 200 mm thick wall 50 per 230 mm thick wall
7 Thermal
Conductivity (Kw-
m/C)
0.16 0.81
8 Mortar Consume
per m3 for 1:6
25 kg of Cement 75 kg of Cement
9 Chemical
Composition
60 % fly-ash which mill with Lime to form
AAC
Soil contain in-organics like
sulphates result in Efflorescence

20. DESIGN OF SLABS WITH U-BOOTS
TOP SLAB DESIGN with Size of slab: 9.76 m × 9.76 m Mixed Design: M25 and Fe415
• DENSITY CALCULATIONS
Density of Reinforced Concrete = 25 KN / m3
Volume of 1 u-boot = 0.021 m3
1 m3 25kN
0.021 m3  ?
25 × 0.021 = 0.525kn
2 u-boot can be placed in 1 m3 of volume density for 2 u-boot = 2 × 0.525 = 1.05 kN/m3
25 – 1.05 = 23.95kN/m3
The density of u-boot material is 35 kg/m3 = 0.343kN/m3
Hence, the final density would become, 23.95 + 0.343 = 24.29kN/m3

21. LOAD CALCULATIONS:-
ASSUMING DEPTH OF SLAB TO BE 150 MM
FOR UNIT WIDTH OF SLAB, DEAD LOAD = 1 × 0.15 × 24.29 =
3.64KN/M3
LIVE LOAD = 0.8KN/M3
TOTAL LOAD, W = 3.64 + 0.8 = 4.44KN/M3
TOTAL FACTORED LOAD WU= 4.44 × 1.5 =
6.66KN/M
TAKING 7KN/M3

22. MOMENTS CALCULATIONS:-
LX = LY= 9.76 M  LY/LX = 1 HENCE, IT IS A TWO-
WAY SLAB
MUX = XWULX
2
= 0.062 × 7 × 9.762 = 41.34KN-M
MUY = YWULY
2
= 41.34KN-M
DEPTH OF SLAB, D = √(MU/0.138FCKB)
= √[(41.34 × 106)/0.138 × 25 × 1000)]
= 109.46 MM < 150 MM
HENCE PROVIDE THE DEPTH OF SLAB OF 150 MM

23. REINFORCEMENT DETAILS:-
AST= (0.36 FCK B XU) / (0.87 FY)
= (0.36 × 25 × 1000 × 0.48 × 150) / (0.87 × 415)
= 1794.76 MM2 (FOR BOTH DIRECTIONS)
ASTX=ASTY= 1794.76/2 = 897.38 MM2
USING 12 MM BARS FOR THE CALCULATION OF SPACING,
S = B AST/AST
= (1000 × Π/4 × 122) / (897.38) = 126.03 MM
NUMBER OF BARS = 9.76/0.126 = 77.38 = 78 BARS IN ONE
DIRECTION
HENCE, PROVIDE 78 BARS OF 12 MM DIA WITH A SPACING OF
126 MM C/C

24. • Check for Shear:-
• Vu = ½ × wu × lx
= ½ × 7 × 9.76 = 34.16 kN
• τv = Vu/bd
= (34.16 × 1000) / (1000 × 150 ) = 0.23 N/mm2
• τc
’ = Pt × k
• Pt = (100Ast)/bd
= (100 × 897.38) / (1000 × 150) = 0.59 %
• Now , calculating the τc value from the Pt value,
0.50 %  0.49
0.59 %  ?
0.75 %  0.57
By using interpolation,
• I get 0.49 + (0.57 – 0.49 )( 0.59 – 0.5 ) / ( 0.75 – 0.5 )
 Pt = 0.5188
• τc
’ = 1.20 × 0.5188 = 0.622 N/mm2
From IS 456:2000, τc max = 2.80 N/mm2
• Now 0.23 < 0.622 <2.80 , i.e.,τv<τc
’<τc max
• Hence it is safe in shear
• Check for deflection:-
• Checking for deflection, especially at the cantilever projections
made from the column strips,
• For Cantilevers, span/leff = 7
• The modification factor for given mixed design is found out to
be around 1.2
• Therefore, 7 × 1.2 = 8.4
• Now, span/leff = 1.22/0.15 = 8.13 < 8.4
• Hence deflection is controlled in the span

25. WEIGHT OF TOP SLAB
U-BOOT BETONS:-
A TOTAL OF 225 U-BOOTS CAN BE PLACED IN SLAB
WEIGHT OF U-BOOT IS GIVEN AS 1.15 KG/PIECE
225 × 1.15 = 258.75 KG
STEEL:-
VOLUME OF STEEL = [156 × Π/4 × 0.0122 × 9.76] × 2
= 0.17 ×2 = 0.34 M3
WEIGHT OF STEEL = VOLUME × DENSITY
= 0.34 × 7850 = 2669 KG
CONCRETE:-
VOLUME OF CONCRETE = TOTAL VOLUME – VOLUME OF STEEL – VOLUME OF U-
BOOT BETONS
= (9.76 × 9.76 × 0.15) – 0.34 – (225 × 0.021)
= 14.28 – 0.34 – 4.725 = 9.215 M3
WEIGHT OF CONCRETE = 9.215 × 2400 = 22116 KG
TOTAL WEIGHT OF SLAB = 258.75 + 2669 + 22116 = 25045 KG
= 245.53KN = 250KN

26. SIMILARLY AFTER CALCULATION, U-BOOT SLABS
DESIGN DETAILS
Details Top slab Intermediate slab Bottom slab Foundation raft
Density (Kn/m3) 24.29 24.29 24.29 24.29
Total factored
load
7 17.2 27.07 35.25
Depth of slab 150 mm 180 mm 280 mm 320 mm
Area of steel for
two way
1794.76 mm2 2153 mm2 3350.22 mm2 3828.83 mm2
Number of bars
Dia of bar
c/c distance
78
12
126
52
16
190
82
16
120
92
16
106
Check for shear
Check for
deflection
OK
OK
OK
OK
OK
OK
OK
OK
Weight of u-boot 258.75 kg 258.75 kg 258.75 kg 423 kg
Steel 2669 kg 3205 kg 5024 kg 5652 kg

27. BRICK WORK CALCULATION
Brick work is calculated for my proposed plan shown below

28. • Plan:- 9.76 m × 9.76 m (outer to outer dimensions)
• Size of full brick:-24” × 8” × 8” = 0.6096 m × 0.2032 m × 0.2032
m
• Size of half brick:-24” × 4” × 8” = 0.6096 m × 0.1016 m × 0.2032
m
• D1 1 × 1.1 × 2 × 0.2032m EXTERNAL DOORS
• D2 2 × 1 × 2 × 0.2032m INTERNAL DOORS
• D3 2 × 0.8 × 2 × 0.1016m WASHROOM DOORS
• W  6 × 1 × 1.2 × 0.2032m
• V  7 × 0.8 × 0.6 × 0.2032m IN LIVING AREA
• V  2 × 0.8 × 0.6 × 0.2032m IN WASHROOMS

29. AFTER CALCULATING THE BRICK WORK
ALONG WITH DEDUCTIONS
BRICK WORK DETAILS BY AAC • BY NORMAL BRICKS
DESCRIP
TION
DESITY
Kg/m3
VOLUME
M3
NUMBER
OF
BRICKS
WEIGHT
KG
Full
brick
625 27.4312 974 17144.5
Half
brick
625 5.6315 382 3519.68
Lintel 2400 0.9911 - 2378.64
mortar 2200 0.0894 - 196.68
TOTAL 23239.5
05 KG
DESCRIP
TION
DESITY
Kg/m3
VOLUME
M3
NUMBER
OF
BRICKS
WEIGHT
KG
Brick
work
1800 59.304 29652 106747
.2
Lintel 2400 1.800 - 4320
mortar 2200 0.0019 - 7.92
TOTAL 111075
.12 KG

30. MAGNETIC REPULSION TECHNIC
• What is Magnetic Repulsion?
• Repulsion is the opposite force of attraction which is obtained when two
like poles of two magnets are tried to brought together
• Why is it used in our foundation?
• Magnets along with a central based together combindly work for
balancing the structure and transferring the loads from above safely to
the raft foundation

31. TYPES OF MAGNETS
• Permanent
neodymium iron boron magnets
samarium cobalt magnets
alnico magnets
ceramic/ferrite magnets
• Temporary
soft iron and any material that behave like magnet
• Electromagnets
Electromagnet is prepared by winding a wire in to several loops around a
core material this is termed as a solenoid. To magnetize electromagnets an
electrical current is passed through the loops to produce a magnetic field Magnetic
field is strong on inside of coil, and strength of the field is proportional to number
of loops and strength of the current.

32.  NEODYMIUM IRON BORON MAGNETS
ARE MADE FROM AN ALLOY OF NEODYMIUM, IRON AND
BORON FOR FORMING A TETRAGONAL CRYSTALLINE
STRUCTURE AND ARE APPEAR SMALL AND COMPACT IN
SIZE
THESE MAGNETS CAN LIFT EASILY THOUSANDS OF TIMES
OF THEIR OWN WEIGHT AND HAS STRONG MAGNETIC
FIELD.
ARE GRADED ACCORDING TO THEIR MAX ENERGY
PRODUCTS, WHICH RELATES TO THE MAGNETIC FLUX
OUTPUT. HIGH VALUE INDICATES STRONG MAGNET AND
RANGE AS FALLOW
N35 TO N52.

33. SAMARIM COBALT MAGNETS
SAMARIUM MAGNETS STRONG AND COMPLICATE TO
DEMAGNETIZATION. AND ARE ALSO HIGH OXIDATION
RESISTANCE, TEMPERATURE RESISTANT WITH STANDING TEMP UP
TO 300 DEGREES CELSIUS.
BASED ON THEIR ENERGY RANGE HAVE TWO SUB CLASSES FIRST
SERIES HAVE A RANGE 15 TO 22 MGOE.
THE SECOND SERIES HAS A RANGE BETWEEN 22 AND 30 MGOE
BUT THEY ARE EXPENSIVE AND HAVE LESS- MECHANICAL
STRENGTH.

34.  ALNICO MAGNETS
ALNICO MAGNETS GOT THIS NAME FROM THE FIRST TWO WORDS
OF ABOVE THREE MAIN INGREDIENTS,
ALUMINIUM,
NICKEL AND
COBALT. ALTHOUGH THEY ARE GOOD TEMPERATURE
RESISTANCE AND CAN EASILY DEMAGNETIZED AND MAY
SOMETIMES REPLACED BY CERAMIC AND RARE EARTH MAGNET IN
SPECIFIC APPLICATIONS, AND ENABLE THE MAGNETS TO REACH
MORE COMPLICATE DESIGN FEATURES.

35.  CERAMIC/ FERRITE MAGNETS
CONSIST OF SINTERED IRON OXIDE AND BARIUM
CERAMIC (OR) FERRITE MAGNET IS TYPICALLY EXPENSIVE
AND EASILY PRODUCE-ABLE, THROUGH PRESSING.
THESE MAGNETS TEND TO BE BRITTLE, SO NEED
GRINDING USING A DIAMOND WHEEL.
IT IS COMMONLY USED MAGNET, IS STRONG AND IS
NOT MUCH EASY FOR DEMAGNETIZE. AND HAVE LESS
ELECTRIC CONDUCTIVITY

36. CHOOSING MAGNET FOR REPULSION
FOUNDATION
IF I GO FOR ELECTROMAGNETS, IT IS EASIER BECAUSE THE
MORE IS THE SUPPLY OF ELECTRICITY, MORE WILL BE THE MAGNETIC
STRENGTH AND LIFETIME. CARE SHOULD BE TAKEN WHILE NOTICING
THE NORTH AND SOUTH POLES IN THE ELECTROMAGNETS
IF I GO WITH NEODYMIUM MAGNET, ENGINEER HAVE TO TAKE
PROPER CARE WHILE HANDLING THESE MAGNETS BECAUSE THESE ARE
VERY POWERFUL. THE LIFETIME OF NEODYMIUM IS ABOUT 100 YEARS,
SO I AM CHOOSING THESE MAGNETS IN MY DESIGN AND FOR
PROTOTYPE.
PRECAUTION WHILE PLACING
THE MAGNETS SHALL BE SO PLACED THAT OTHER THAN THE
REPULSION CHAMBER, THE WHOLE REMAINING AREA MUST BE
COVERED WITH A MAGNETIC RESISTANT MATERIAL LIKE RUBBER SO
THAT THE MAGNETIC LINES DOES NOT AFFECT THE REINFORCEMENT
AND OTHER MAGNETIC MATERIALS IN THAT AREA

37. PLACING OF
MAGNET
PROTOTYPE

38. RESULTS
MATERIAL CONVENTIONA
L
Ideal by
batons and
AAC blocks
density Rcc 1st floor 357.22 KN 245.42 KN
2nd floor 428.65 KN 316.41 KN
3rd floor 666.80 KN 552.86 KN
Raft
foundation
762.06 KN 526.64 KN
weight Total Brick work 1650
KN/structure
375
KN/structure
quantity Steel 1st floor 26.15 KN 26.15 KN
2nd floor 31.40 KN 31.40 KN
3rd floor 49.23 KN 49.23 KN

39. CONCLUSION
• I am concluding that there is an enormous decline in the weight of
the structure.
• U-boot baton structure takes excess care when compared to that of a
conventional one.
• The whole magnet system on the mat foundation will act as columns
poles reflection
• Comparing the weights of conventional brickwork and AAC brickwork
system, we see a rate of almost 4.4 times of heavy weight using
conventional. Hence by using AAC Blocks, we can reduce the weight
from 1650 kN to 375 kN, i.e., decrease of about 4.4 times.
• U-boot and AAC building structures with mat foundations are
suitable in such soil conditions where the bearing capacity of soil is
poor.

40. THANK YOU VERY MUCH
QUERIES IF ANY