presentation on mat foundation

PRESENTATION ON

MAT FOUNDATION

Department of Civil Engineering

1

AHSANULLAH UNIVERSITY OF

SCIENCE & TECHNOLOGY

Presented byName

• Md. Abdul Ahad• Monisha Podder Puja• Arafat Chowdhury• Sabrina Zissan• Mahbub Al Muhaimin• Md. Abu Bakar Siddik• Sabrina Mehenaz• Tanvir Alam Khan• Md. Ashraf Ali• Amit Kumar Baral

ID• 12-01-03-104• 12-01-03-110• 12-01-03-110• 12-01-03-124• 12-01-03-129• 12-01-03-136• 12-01-03-144• 12-01-03-149• 12-01-03-154• 11-02-03-16

Visited Sites

Arham Tower, Uttara

Pallabi, Mirpur-11

Euro Bangla Real Estate, Mouchak

MAT Foundation• a primary shallow foundation;• a large footing extended over the whole

construction area;• Usually large concrete slab supporting

many columns;• Commonly used as foundation for high

rise buildings with basement;• Mat is also known as Raft;• Usual depth 1~20 feet.

PCC BED

R C C SLAB

C C

Sectional View

Plan View

COLUMN

MAIN BEAM

SECONDARY BEAM

MAIN BEAM

When we construct MaT foundation?

• When the area of individual column footings cover more then 50% area of total land;

• When the bearing capacity of soil is too weak to support a structure;

• When the cost of deep foundation is higher then Raft foundation.

• When the structural load is too high.

Types of MAT• Flat plate mat• Plate thickened under columns• Two-way beam and slab• Plate with pedestal• Rigid frame mat• Piled raft

construction ProceduresSoil test

Shoring & Water

proofing

Partial Excavation (depending on depth)

Bracing (depending on depth)

Full area excavation

Soil compaction

BFS & CC or LC layer cover

Reinforcement placing Shuttering

Casting & Compaction

Shuttering removal

Curing

Soil Test• Bearing capacity of soil;

• Soil classification;• Ground water level;• Moisture content;• Appropriation & depth of MAT.

Shoring• Shoring is commonly used when installing the

foundation;

• Shoring support the surrounding loads until the underground levels of the building are constructed.

• Can be of 3 types: Pile shore, steel sheet shore and timber shore.

Log Shore Pile Shore

Water proofing• A layer provided over shoring to prevent moisture;

• Cement mortar or steel sheet layer over shoring;

• Cement mortar layer is extended over wire mesh.

Bracing• A horizontal support for

the boundary shores during excavation and foundation;

• Depends on the depth of foundation;

• Also known as horizontal shores.

Other factors

Shotcrete leveling layer with steel mesh

Retaining Wall

King Post

BFS and CC

Layer of bricks on the earth

Layer of cement concrete over BFS.

Reinforcement placing• Single horizontal reinforcement placing;

• 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.

Important factorsReinforcement Selection• 60~72.5 Graded • 12mm~25mm

Reinforcement Joint• Heavy Steel wire binding

Chair• Distance• Bending

Important factorsHook• Right angled

Rod Cutter

Rod bender

Shuttering• Steel plate shutter;• Timber shutter.

Cast Material• Mixture ratio 1:2:4;• Sylhet sand is used over 50%;

• Stone chips that are used normally is ½”~¾” in size;

• Stone chips are preferred than brick chips.

Casting• Start from one end;• Layer basis casting;• Side basis casting.

Compaction• By vibrator machine;

• Compaction and casting both are done simultaneously;

Precautions for casting• Materials like piece of wood, polythene etc. must be

removed before casting from that area;

Curing