This powerpoint presentation was based on construction steps of mat/raft foundation

1. PRESENTATION ON MAT FOUNDATION
Ahsanullah University of Science and Technology
Dept. of Civil Engineering
CE-200
Details of Construction

2. What Is Foundation ?
1. It is the load bearing structure that is directly connected to
the ground
2. Transfers all the load directly to soil.
3. It provides a level surface for building operations

3. Types of Foundation

4. MAT FOUNDATION
It’s a one continuous large footing spread over the entire construction area.
It’s a thick slab having many columns which transfers loads coming through
the columns directly to the soil.

5. Types Of MAT foundation
Mat Foundation
Flat Plate Mat
Plate thickened
under the
column
Two way beam
and slab raft
Plate raft with
Pedestals
Piled Raft Rigid Frame Mat

6. Why Mat Foundation Is Required ?
When foundation area cover 50-60% of the total plot area
When the bearing capacity of the soil is too low
When Basement is needed

7. We Visited
Sites We Visited
We Visited
Site 1 : Bosnia Sir’s Project ,
7/1, Kallyanpur, Mirpur Rd,
Dhaka 1216 Dhaka
Site 2 : Assure Group Project,
Gulshan 1 Rashid Tower, Rd
21, Dhaka 1212,
Site 3 : Dolmen Prime project , H-
8, Block-H, Main Road, South
Aftabnagar, Dhaka 1219

8. Construction Steps of a Mat Footing
Soil Test
Leveling
Shoring
Soil Excavation
Providing
Strutting and
Bracing
Compaction
and Leveling
of Soil
Provide
POLYTHENE ,
BFS , CC layer
Placing CC
block beneath
bottom layer
reinforcement
Placing of
Reinforcement
Concreting
Vibrating
Leveling Curing

9. Step 01
Soil Test
• Soil is tested for measuring
capacity
• Mat Foundation is applied if
bearing capacity is too low.

10. Step 02
• Centering provides
accurate height
• Ease of depth
measurement
• Creates suitable terrain for
excavation equipment
• Creates a level surface
to work on

11. Step 03
• To protect from shear failure of soil
• Facilitates safe underground working conditions
Concrete Pile Shore Timber Pile Shore

12. Step 04
• Removes unnecessary substratum
• Provides necessary depth for placing BFS,CC & reinforcements

13. Step 05
• Prevents shoring from collapse due to overturning
• Provides lateral support to shoring

14. Step 06
• Prevents structure from leaning one side to another
• Provides level working surface

15. Step 07
• First one layer of brick flat soling is placed over the area It prevents structure from
leaning one side to another
• After that Cement concrete layer of 3” thickness is provided.
• Makes structure less susceptible to ground water table
BFS LAYER CC LAYER

16. Step 08
• Blocks are provided to maintain clear cover at the bottom
• Provides protective cover for rebar through concreting

17. Step 09
• Main bar on bottom mesh is placed
• Chair is placed to hold the top mesh at desired height

19. • Provides the formwork for concrete placement
• Facilitates providing desired shape to concrete

20. Step 10
• Provides the majority of compression resisting material
• Works in tandem with rebar to provide desired structural strength

21. Step 11
• Removes void from concrete mix
• Ensures proper consolidation

22. Step 12
• Ensures level surface
• Provides smooth finishes

23. Step 13
• Provides suitable condition for hydration reaction
• Immersed in water continuously for 28 days to obtain ultimate strength

24. Advantages:
 Great for building Basement
 It reduces differential settlement.
 The foundation and floor slab is combined , which saves time.
 Distributes loads over a larger area.

25. Disadvantages:
 Mat foundations need heavy reinforcement in certain areas, which can add up to
the price of the manufacture
 As the slab has greater thickness, heat may trap inside during hydration reaction.
 Water may seep inside.
 Shore protection is needed.

26. • This presentation is based on the observations on Mat Foundation in various sites
& meeting with concerned Engineers & Workers.
• The principal objective of this Presentation is to learn about Mat Foundation
practically with structural view.
• Besides Mat Foundation we were able to learn other major & minor parts of a
construction.

27. That’s All , Thank You !

28. COPYRIGHT
This presentation is copyright protected by Tahey Bin Mainur, department of Civil
Engineering, Ahsanullah University of Science & Technology (AUST), Dhaka,
Bangladesh, 2017.
If you want to present or use these slides for any purposes kindly please contact me..
Thank you for watching & your precious time !