presentation on mat foundation
TRANSCRIPT
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