This Presentation is done by students of Ahsanullah University of Science & Technology for CE 200 (Details of Construction) course. MAT foundation is a type of shallow foundation which is frequently constructed nowadays for specially basement pupose. Here, how mat foundation is constructed is described shortly. This slide is copyright protected by MD. Ashif Rayhan Shuvo, Civil Department, AUST, Dhaka, Bangladesh. If you want to present or use these slides for any purpose, please contact to MD. Ashif Rayhan Shuvo. Thank you for watching & your precious time.

1. PRESENTATION ON MAT FOUNDATION
DETAILS OF CONSTRUCTION
Submitted By:-
Group-04, 2nd Year, 2nd Semester, Section-C, Department Of Civil
Engineering
AHSANULLAH UNIVERSITY OF SCIENCE &

2. Contributed By:-
Md. Ashif Rayhan Shuvo (12.02.03.041) (Compiler)
Nadia Akter Munni (13.01.03.126)
Md. Rokanuzzaman (13.01.03.135)
Musarrat Mubasshira Atiya (13.01.03.138)
Md. Muntasir Salehin (C) (13.01.03.147)
Abdullah Al Kafi (13.01.03.159)
Mustafidul Hoque (13.01.03.166)
Tony Islam (13.01.03.168)
Ashiqur Rahman Prottoy (13.01.03.172)

3. CONTENTS
Definition of Mat or Raft foundation
When Mat foundation should be provided
Types of Mat foundation
Plan & Sectional view
Visited Sites
Construction Flow Chart
Constructing a Mat foundation
Advantages & Disadvantages
Conclusion

4. Mat Foundation
A continuous, thick, concrete slab foundation heavily reinforced with
steel supporting an entire structure.
It is a type of shallow foundation (depth ≤ width).
All the columns are connected to an large RCC slab and the slab is
directly contact with the soil.
All vertical structural loadings from columns and walls are supported
on the common foundation.
Generally used in heavy industrial plant, official and commercial
buildings and sometimes in residential buildings.

5. Sketch Of a Mat
Foundation

6. When Mat foundation should be provided
If foundation area covers 50-60% of the total plot area.
If the individual columns or footings would be undesirably close
together or try to overlap.
It is required where soils have low bearing capacity and have to
support heavy structural loads.
Structures on marshy land, soft clay and land that are made up of
sanitary land fill or other materials (like debris, unconsolidated soil
and solid waste etc.) where differential settlement is suspected.

7. Types Of Mat Foundation
Flat Plate Mat Flat Plate
Thickened Under
Column
Two-way Beam &
Slab
Plate with
pedestals
Piled Raft Rigid Frame Mat

8. Sectional Design Of A Mat Foundation

9. Plan View
Main Beam
Secondary
Beam
Colum
n
Sectional
View
BFS & CC
Layer
RCC
Slab
Main
Beam
Colum
n

10. Visited Sites
Credence, Road-7/A, Dhanmondi,
Dhaka
Biswas Builders Limited, Road-9/A,
Dhanmondi, Dhaka

11. Construction Flow
Chart
1
• Soil Test
2
• Shoring
• Water
Proofing
3
• Partial
Excavation
(Depending upon
depth)
4
• Strutting
• Bracing
5
• Full Area
Excavation
6
• Soil
Compaction
7
• BFS Layer
• CC Layer
8
• Reinforcemen
t Placing
9
• Casting of
RCC
• Compaction
10
• Curing
11
• Removal of
Shuttering
• Further Curing
12
• Retaining Wall
• Shear Wall

12. Soil Test
Bearing capacity of soil
Soil classification
Void ratio
Compressibility characteristics of the
soil
Presence & amount of garbage in soil
Ground water level
Moisture content
Depth of Mat

13. Shoring
Creates a continuous wall along the boundary.
Supports the load of the surrounding structures during
construction.
Prevents the surrounding soil from breaking during construction.
Prevents the collapsing of the existing structure.
Protects the existing structure from vibration.
Remains in the ground and serves as a retaining structure.
Can be of three types: Concrete pile shore, Steel sheet shore,
Log shore.

14. Figures of Log Shoring

15. Steel Sheet Shore Concrete Pile Shore

16. A temporary wall is provided very next to the shoring so that deposited water
can’t enter into the construction site.
A cement mortar layer is provided over shoring to prevent moisture.
Water Proofing

17. Earthwork Excavation
Partial & Full Excavation is
required before further construction.
Soil Compaction
After full excavation, soil
compaction is needed to obtain a
uniform surface for the placement
of BFS and other layers.

18. Bracing & Strutting
A horizontal support system for the
boundary shores during excavation
and foundation.
Its requirement depends on the
depth of foundation.
Generally made of steel sheet.
Also known as horizontal shores.

19. Braces are the orthogonal members in the system.
Strut is the inclined member joining two perpendicular braces.
King posts are the vertical compression members supporting the brace & strut
system.

21. Reinforcement Placing
Placement of a batch of horizontal
bar;
Placement of another batch of bar
to complete the bottom mesh;
Placement of Column bars;
Placement of vertical rod (chair)
over bottom mesh to hold the
upper mesh;
Upper mesh placement.

22. Bottom Mesh Retaining Wall Bar Placement
(Along with bottom mesh placing)
& Column Placement

23. Chair Placement Upper Mesh Placement
Chair
Bottom
Mesh
Upper
Mesh
CC
Block

24. Sectional View Of Mat Mesh Joint Between Column Footing & Mat
Mesh
Upper
Mesh
Bottom
Mesh

25. Joint Between Reinforcement
of Column & Mat Mesh
Tie
Chair
Inclined
Bar to
hold the
Column
straight
Finished Reinforcement Placement

26. Other Factors
Reinforcement
Selection
 60~72.5 Graded
 12mm~25mm
Rod
Cutter
Rod
Bending
Chair
Reinforcement Join
(with heavy steel wire)
Tie
Bar

27. CC Block
(to maintain Clear Cover)

28. Shuttering
Timber Shuttering Steel Plate
Shuttering
Brick Wall used as a
Shuttering of Column Footing
(remains as a part of foundation)

29. Casting
Side basis casting
Layer basis casting
Casting in Mat Mesh Casting in Footing

30. Compaction
Casting & Compaction both are done simultaneously.
Compaction is generally done by vibrator machine.
Vibrator
Machin
e

31. Leveling
After casting & compaction, leveling is a must to
get the same thickness all over the mat slab.
Leveling with
Patta

32. Curing
Spraying or Fogging Ponding
Saturated Wet
Coverings (By
Hessian or Gunny

33. Retaining Wall & Shear
Wall
Reinforcement Placing Shuttering Casting
Retaining wall is provided in basement to prevent lateral load of the surrounding
soil.
Shear wall is a wall that is designed to resist shear & the lateral force (wind,

34. Advantages
The foundation and floor slab is combined, which saves time and
materials.
Loads are spread over the whole area of the structure.
It can cope with mixed or poor ground condition.
It requires little excavation.
It reduces differential settlement.
Disadvantages
Large thickness, expensive.
Shore protection is needed.
Susceptible to edge erosion.
Weak when supporting point loads, specific treatment required.
Advantages &
Disadvantages

35. Conclusion
 This presentation is based on the observations on Mat foundation in
various sites & meeting with concerned engineers & workers.
 The purpose of this presentation was to gather some practical
experience on Mat foundation.
 During the making of this presentation, we also practically
experienced other major & minor parts of a construction.

37. Thank You
All !!