PRECAST CONCEPT

1. PREFABRICATED WALL
PANEL

2. CONTENTS:
1. Introduction
2. Features
3. HISTORY
4. Prefabricated ,advantage and disadvantage
5. Concrete wall panel ,advantage and disadvantage
6. TYPES OF PRECAST COMPONENTS IN A BUILDING
7. PRECAST AND PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
8. EQUIPMENTS USED IN PRECAST CONSTRUCTION
9. Type of precast system
10.Assemble and connection
11.Joint in slab and its types

3. Introduction:
1. The concept of precast structures also known as prefabricated/ modular structures.
2. The structural components are standardized and produced in plants in a location away from the
building site.
3. Then transported to the site for assembly.
4. The components are manufactured by industrial methods based on mass production in order to build a
large number of buildings in a short time at low cost.
Features:
1. The division and specialization of the human workforce.
2. The use of tools, machinery, and other equipment, usually automated, in the production of standard,
interchangeable parts and products.
3. Compared to site-cast concrete, precast concrete erection is faster and less affected by adverse
weather conditions.
4. Plant casting allows increased efficiency, high quality control and greater control on finishes.

4. HISTORY:
1. Ancient Roman builders made use of concrete and soon poured the material into moulds to build their
complex network of aqueducts, culverts, and tunnels. Modern uses for pre-cast technology include a
variety of architectural and structural applications featuring parts of or an entire building system.
2. In the modern world, precast panelled buildings were pioneered in Liverpool, England, in 1905. A
process was invented by city engineer John Alexander Brodie, whose inventive genius also had him
inventing the football goal net. The tram stables at Walton in Liverpool followed in 1906. The idea was
not taken up extensively in Britain. However, it was adopted all over the world, particularly in Eastern
Europe[4] and Scandinavia.
3. In the US, precast concrete has evolved as two sub-industries, each represented by a major
association. The Precast Concrete Products industry focuses on utility, underground, and other non-
prestressed products, and is represented primarily by the National Precast Concrete Association
(NPCA). The Precast Concrete Structures industry focuses on prestressed concrete elements and on
other precast concrete elements used in above-ground structures such as buildings, parking
structures, and bridges. This industry is represented primarily by of the Precast/Prestressed Concrete
Institute (PCI).

5. What is prefabricated?
Prefabricated: A Structure fabricated at an offsite location and brought to the site as fully assembled for
installation.
What is wall panel?
wall panel: A wall panel is a single piece of material like concrete , timber , masonry etc usually flat and cut into
a rectangular shape.
What is prefabricated wall panel?
prefabricated wall panel: A Structure fabricated at an offsite location , construct structure like column , beam,
slab and panel use material such as concrete , reinforcement etc.
WHAT do you mean by panel?
PANEL: It is distance between two adjacent support or joints.
Advantage of prefabricated wall panel:
1. It can construct easily.
2. Reduce labor and material cost.
3. Wall panels are decorative, providing insulation and soundproofing.
4. Easy to replace.
5. It is a framework structure.
6. Finishing is easy.
7. Resist weathering agencies.
8. Low maintenance.
9. Save time and energy.

6. Disadvantage of prefabricated wall panel:
1. This structure is Less used.
2. It is necessary to arrange for special equipment for lifting and moving.
3. If not properly handled, the precast units may be damaged during transport.
4. Initial cost is high.
Types of wall panel:
1. Concrete panel
1. CONCRETE WALL PANELS: Those panel is made up of concrete is called concrete wall panel.
ADVANTAGE:
1. It is not necessary to provide joints in the precast construction.
2. The work can be completed in a short time, when precast units are adopted.
3. When precast structures are to be installed, it is evident that the amount of scaffolding and
formwork is considerably reduced.
4. Precast concrete provides excellent protection against impacts from explosions, vehicles and
projectiles.
5. This panel is easy to install.
6. It resist weathering agencies.
7. Precast concrete requires little or no maintenance as compare to other material.
8. Precast concrete wall panels offer costs when compared with other materials.
9. It is high Efficiency.

7. DISADVANTAGE:
1. If not properly handled, the precast units may be damaged during transport.
2. It becomes difficult to produce connections between the precast members.
3. It is necessary to arrange for special equipment for lifting and moving of the precast units.
4. Skilled workmanship is required in the application of the panel on site.
5. cranes are required to lift panels.

8. TYPES OF PRECAST COMPONENTS IN A BUILDING:
1. Precast Beams:
1. Internal beams – where floor loading is approximately symmetrical
2. External beams – where floor loading is predominantly nonsymmetrical.
2. Precast Columns: For structures of five storey or less, each column will normally be continuous to the full
height of the building. For structures greater than five storey two or more columns are spliced together.
The main types of precast columns are:
1. Edge columns – symmetrical in one direction.
2. Internal columns – symmetrical in all directions.
3. Corner columns – not symmetrical at all.
3. Precast floor slabs:
1. Hollow cored slab
2. Double tee slab
4. Precast walls:
Precast concrete walls serve two functions:
• Stability
• As walls or boxes surrounding staircases and lift shafts.
Walls may be classified as infill or cantilever:
• Infill walls rely on contiguous composite action with the beam and column frame.
• Cantilever walls or boxes act as deep beams to which the frame is attached.

9. 5. Precast staircases: Three options are available for precast staircases:
1. A single precast unit containing all the flights and landings.
2. Separate precast flights and landings.
3. Parts of the flights and landings are made in one piece.

10. PRECAST AND PRESTRESSED CONCRETE STRUCTURAL ELEMENTS:
1. Precast Concrete Slabs: it is a horizontal member , a large, thick, flat piece of stone or concrete, square or
rectangular in shape . It is used for floor and roof decks.
TYPES OF SLAB:
1. SOLID FLAT SLAB : A flat slab is a two way reinforced concrete slab that usually does not have beams and
girders, and the loads are transferred directly to the supporting concrete columns.
The column tends to punch through the slab in Flat Slabs , which can be treated by three methods:
1. Flat slab with drop panel: uses
1. Drop panels increase shear strength of flat slab floor.
2. Drop panels increase flat slab's negative moment capacity.
3. Drop panels reduce deflection by stiffening the flat slabs.
2. Flat slab with column head: uses
1. Shear strength of flat slab is increased by using column heads.
2. Column heads reduce the clear or effective span, and therefore, reduce the moment in the flat slab floor.
3. Flat slab with column head and drop panel
2. HOLLOW CORE SLAB: A hollow core slab, also known as a voided slab, it is a precast slab of prestressed
concrete typically used in the construction of floors in multistory apartment buildings.
LENGTH WITH OR WITHOUT PRESTRESSED WIRE ROPE:
. The precast concrete slab has tubular voids extending the full length of the slab , diameter is 2-3 to 3-4. The
slabs are 120 cm wide with standard thicknesses between 15 cm and 50 cm.
• Reinforcing steel wire rope provides resistance to bending moment from loads. Slabs in prestressed concrete
are usually produced in lengths of up to 200 meters

11. . In without prestressed steel rope wire ,The size of these elements will typically range in width from 600 to
2400 mm, in thickness from 160 to 500 mm, and can be delivered in lengths of up to 24 m.
void: voids in the hollow core slabs reduce weight and cost and can conceal or cover electrical or
mechanical runs.
3. Double tee : double T beam is a load bearing structure that resembles two T beams connected to each
other side by side.
Flange horizontal structure and web vertical member creates a structure that is capable of withstanding high
loads while having a long span.
Size of double tee slab flange width is 4.6m and web depth is 1.5m , span length is 24m or more.
4. Single tee : single T beam is a load bearing structure that resembles one T beams connected to slab.
They are used to provide spans ranging from 30 to 100 feet. Single-tees may be placed flange to flange.
Span length ranging to 3.5m to 30m.
T BEAM : Flange is compression member resist compressive stress and Web is vertical member resist
shear stress.
1. Compressive stress is the stress on materials that leads to a smaller volume.
2. Shear stress is a stress state where the stress is parallel to the surface of the material, as opposite to
normal stress when the stress is vertical to the surface.

12. BEAM: BEAM is a horizontal structural member, a long piece of timber or metal used to support the roof
or floor of a building. It transfer the load on column. Example : Purlin , girder etc.
OR
A beam is a structural element that is capable of withstanding load primarily by resisting against bending.
TYPES OF BEAM:
1. RECTANGULAR BEAM
2. L SHAPED BEAM
3. INVERTED TEE BEAM
4. AASHTO BEAM

13. EQUIPMENTS USED IN PRECAST CONSTRUCTION:
Cranes:
1. Mobile crane: A mobile crane is a cable controlled crane mounted on crawlers. A crane is a type of
machine, generally equipped with a wire ropes and sheaves, that can be used both to lift and to move
them horizontally . It is used for lifting heavy things and transporting them to other place.
2. Tower crane (above 3stories): A mobile crane is a cable controlled crane mounted on crawlers.
A crane is a type of machine, generally equipped with a wire ropes and sheaves, that can be used both
to lift and to move them horizontally . It is used for lifting heavy things and transporting them to other
place.
Maximum reach: 230 feet (70 meters)
Maximum lifting power : 19.8 tonne (20 tonne)
Lifting tools:
1. spreader beams: A spreader bar is a type of below the hook lifting device used to aid crane
operators in picking up large and sometimes heavy loads.
2. wire rope slings
rigging tools:
1.eye bolt : on the element lifting point.
2.shakles : on the element lifting point.
3. hooks: attach for the crane.

14. Types of pre cast system:
1. Large-panel systems: it is box-like
structure. In which both vertical and
horizontal elements are load-bearing.
2. Frame system : Components are usually
linear elements. The beams are seated on
corbels of the pillars. Joints are filled with
concrete at the site.
3.Slab-column systems with walls
4.Mixed systems
Assemble : Structure member or parts
to put and connected together with the
help of device and material.
1. Column to column connection: Metal
bearing plates and embedded anchor bolts
are cast into the ends of the columns.
After the columns are mechanically joined,
the connection is grouted to provide full
bearing between elements and protect the
metal components from fire and corrosion.

15. 2. Beam-to-Column
Connection :
Beams are set on bearing
pads on the column
corbels .
Steel angles are welded to
metal plates cast into
the beams and
columns and the joint
is grouted solid.

16. 3. Slab-to-Beam
connection:
1. Hollow core slabs are
set on bearing pads
on precast beams.
2. Steel reinforcing bars
are in inserted into
the slab keyways to
span the joint.
3. The joint is grouted
solid.
4. The slab may remain
on topped with
several inches of cast
in place concrete.

17. 4. Sitecast Concrete
Toppings over
Precast Slabs:
1. Greater floor strength
and stiffness.
2. Greater fire resistance.
3. Greater acoustic
isolation.
4. Allow easy integration
of electrical services
into floor system.
5. Create a smoother,
flatter floor surface.

18. 5. Precast Concrete Construction and Seismic Design:
1. In areas of high seismic risk, structures must be designed to respond safely to the dynamic forces
imparted into the structure.
2. Innovations in joint design are improving the connection systems in precast concrete structures and
making them increasingly suitable for use in such areas.
Joint: A point at which parts of an artificial structure are joined.
Type of Joints in Slab
1. Control joint ﴾ contraction joints ﴿ : it is used in slab to prevent cracking due to shrinkage .
2. Isolation joint ﴾ expansion joints ﴿ : An expansion joint or movement joint is an assembly designed to
safely absorb the heat-induced expansion and contraction of construction materials, to absorb
vibration, to hold parts together.
3. Construction joint: these are placed where concrete pouring stops for the day to prevent moisture
penetration into the interior space.

19. THANK YOU