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PRESENTATION ON MAT FOUNDATION
DETAILS OF CONSTRUCTION
CE-200
Compiled By–
Group-03, 2nd Year, 2nd Semester, Section-C, Department of Civil Engineering,
AHSANULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY
Contributed By-• Md Abdul Aahad (GL) (12-01-03-104)
• Monisha Podder Puja (12-01-03-110)
• Arafat Chowdhury (12-01-03-116)
• Sabrina Zissan Rafa (12-01-03-124)
• Md. Mahbub Al Muhaimin (12-01-03-129)
• Md. Abu Bakar Siddik (12-01-03-136)
• Sabrina Mehenaz (12-01-03-144)
• Tanvir Alam Khan (12-01-03-149)
• Alamin Bhuiyan Ashraf (12-01-03-154)
• Amit Kumar Baral (11-01-03-016)
CONTENTS
• Definition Of Mat Or Raft Foundation
• Reasons For MAT Foundation
• Types Of Mat Or Raft Foundation
• Procedure Flow Chart
• Plan & Sectional View
• Visited Sites
• Constructing A Mat Foundation
• Advantages & Disadvantages
• Conclusion
MAT FOUNDATION
• A foundation system in which essentially the entire building is placed on a large
continuous footing.
• Usually large concrete slab supporting many columns.
• Commonly used as foundation for official or commercial spaces, residential
buildings, chimneys & large machinery.
• It is a flat concrete slab, heavily reinforced with steel, which carries the downward
loads of the individual columns or walls.
Reasons For Mat Foundation
The spread footings cover over 50% of the foundation area because of large
column loads.
The soil is soft with a low bearing capacity.
When the expenses of deep foundation is higher then raft foundation.
TYPES OF MAT
Flat Plate MatTwo-way Beam & SlabFlat Plate Thickened Under
Column
Flat Plate with Pedestals Pile Mat Rigid Frame Mat
PROCEDURE FLOW CHART
Soil Test ( For Bearing
Capacity)
Shoring & Water Proofing
Partial Excavation(Depending
upon Depth)
Strutting & Bracing
Full area Excavation
Soil Compaction
BFS & CC or LC layer cover
Retaining Wall
Reinforcement Placing
Casting of CC & Compaction
Curing
Sectional Design of a Mat Foundation
PCC BED
R C C SLAB
C C
Sectional View
Plan View
COLUMN
MAIN BEAM
SECONDARY
BEAM
MAIN BEAM
Visited Sites
Arham Engineers Limited, Uttara, Dhaka
Aine Properties, Mirpur-11, Dhaka
Euro Bangla Real Estate, Mouchak, Dhaka
• Bearing capacity of soil;
• Soil classification;
• Ground water level;
• Moisture content;
• Appropriation & depth of Mat.
Soil Test
o Shoring is commonly used when installing the foundation;
o Shoring support the surrounding loads until the underground levels of the
building are constructed.
o Can be of 3 types: Pile shore, steel sheet shore and timber shore.
Shoring
Log Shore Pile Shore Steel Shore
Figures of Shoring
A layer provided over shoring to
prevent moisture;
Cement mortar or steel sheet layer
over shoring;
Cement mortar layer is extended over
wire mesh.
Water Proofing
# Partial & Full Excavation is required
before the Bracing, Strutting, BFS &
Placement of Reinforcement etc…
Earthwork Excavation
A horizontal support for the boundary
shores during excavation and
foundation;
Depends on the depth of foundation;
Also known as horizontal shores.
Strutting & Bracing
King Post
Strut & Brace
Strutting at First & Second Phase
Layer of bricks
on the earth
Layer of cement concrete
over BFS.
A batch of horizontal reinforcement placing;
Another batch of reinforcement placement to
complete the bottom mesh;
Column rod placement;
Vertical rod (chair) placement over bottom
mesh to hold the upper mesh;
Upper mesh placement.
Placing of Reinforcement
Joint Between Column footing & Mat Mesh
Placed Reinforcement for Mat Mesh Joint Between the reinforcements
of Column & Mat Mesh
Reinforcement Selection
• 60~72.5 Graded
• 12mm~25mm
90°/135° Hook
Chair
CLEAR COVER
• Start from one end;
• Layer basis casting;
• Side basis casting.
Casting
RCC in Mat Mesh Casting in Mat Slab
Leveling
After casting the whole Mat area leveling is essential to
be ensured that the thickness of the mat slab is same all
over the area.
Advantages & Disadvantages
Raft or Mat foundation is economic due to combination of foundation and floor slab.
It requires little excavation.
It can cope with mixed or poor ground condition.
It reduces differential settlement.
Mat foundation requires specific treatment for point loads.
Edge erosion occurs if not treated properly.
Disadvantages
Advantages
CONCLUSION
• 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.
COPYRIGHT
This presentation is copyright protected by Arafat Chowdhury, department of Civil
Engineering, Ahsanullah University of Science & Technology (AUST), Dhaka,
Bangladesh, 2014.
If you want to present or use these slides for any purposes kindly contact to Arafat
Chowdhury.
Thank you for watching & your precious time !