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 !