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Assalamualaikum & Good Morning
Think Good and Do Good Things Only
SLAB
What is Slab???
“A flat piece of concrete, typically used as a
walking surface, but may also serve as a load
bearing device as in slab homes.”
FUNCTION
Provide a flat surface To support load Sound, heat and fire insulator Act as a divider (privacy) for the occupants Upper slab became the ceiling for the
storey below Space between slab and ceiling can be used
to place building facilities
Classification of Slab
GROUND FLOOR
UPPER FLOOR
SOLID FLOOR
SUSPENDED GROUND FLOOR
TIMBER FLOOR
REINFORCED CONCRETE FLOOR
PRECAST FLOOR
Classification of Slab
GROUND FLOOR
UPPER FLOOR
SOLID FLOOR
SUSPENDED GROUND FLOOR
TIMBER FLOOR
REINFORCED CONCRETE FLOOR
PRECAST FLOOR
Characteristic of Ground Floor
Simple design Load will be supported by the ground Less problem related to distance of span Choice to construct solid floor or
suspended ground floor will depends on nature of the building and site condition
DESIGN CONSIDERATION
Among the design function that need to be taken
in consideration for construction of ground floor
slab is
• The provision of a uniform, level surface
• Sufficient strength and stability
• Exclusion of dampness from inside of building
• Thermal insulation (max.0.45 W/square metreK
• Resistance to fire
Solid Floor
Solid Floor / Non Suspended Floor
Constructed using concrete Doesn’t use timber so there will be no
decay Solid floor need other finishing
Construction Of Solid Floor
1) Clear the construction area
2) Remove topsoil / unsuitable material (225 mm)
3) Compact and level the soil
4) Place hardcore and compact itHardcore plays the role to fill in any small pockets that have formed during oversite excavation in order to provide a firm base for placing concrete bed and to help spread any point loads over a greater area.
5) Place Damp Proof Membrane
6) Prepare formwork
7) Prepare lean concrete (50 – 75mm) in order to ensure the reinforcement didn’t touch the ground.
8) Place Reinforcement Bar to increase strength
9) Pour concrete (1:2:4) with thickness of (150mm) and level it.
10)Place concrete of (25-50mm ) thickness . (rendering process)
Topsoil Is Stripped
AFTER
BEFORE
Rebar Used For Slab Construction
Pouring concrete
Concrete Slab Finishing
Screeding is the process removes excess concrete and
brings the top surface of the concrete to proper grade.
SUSPENDED GROUND FLOOR
SUSPENDED GROUND FLOOR
A ground floor need to be suspended under the following condition:a) domestic buildings on sloping sites where more than 600mm depth of infill would be requiredb) where the bearing capacity and nature of the
ground different from one part to anotherc) where the ground is shrinkable clay, expansive material or unstable soil type.
Suspended floors / slab is fixed some distance above the ground.
There are 2 types of suspended ground floor such as a) Suspended timber ground floorsb) Suspended precast concrete floors
Suspended Timber Ground Floor
Suspended Timber Ground Floor
it has some flexibility and will accept nail fixing (solid ground floor can’t use nail)
Under side of ground floor must kept dry to prevent fungus attack
Susceptible to dry rot and draughts but it can be avoided if the floor is designed correctly.
Adequate ventilation under the floor and correct positioning of dampproof courses can keep the under floor area and timber dry.
Space beneath the suspended timber floor is ideal for running electric cables, water pipes and gas pipes
It’s more expensive form of construction than concrete floor
Cheaper than precast concrete flooring system
UPPER FLOOR
Timber Floor / Timber Slab
• Lantai Papan Tunggal
• Lantai Kayu Kembar
Precast Concrete Floor
PRECAST CONCRETE FLOOR
Advantages of Precast Concrete floor isa) Doesn’t need formwork
b) Time taken for concrete to cure in the formwork can be eliminatedc) Better quality control d) Doesn’t need many workers as in in-situ concrete constructione) fast completion of construction project
long spans available with precast concrete flooring systems reduce the number of secondary beam required and maximize the column free space.
Fire resistance ratings normally between 1 & 2 hours
Among the things that need to be considered before considering any system of precast concrete flooring are: a) maximum span f) Sound insulation b) nature of support g) Thermal insulation propertiesc) weight of units h) Fire resistance of unitsd) thickness of units i) Speed of constructione) Amount of temporary support required
There are many types of precast concrete floor such as :a) Precast Hollow Floorsb) Composite floors
Precast hollow floor units are available in a variety of sections such as box planks / beams, tee section, I beam sections and channel sections.
Composite floors are combination of precast units and insitu concrete.
Precast Hollow Slab
Precast Hollow Floors
more economic compared to in-situ floor due to reduction in volume of concrete used, weight of reinforcement and size of foundation.
cheaper than composite in-situ concrete is not required Units are self centering so, no need temporary
support Construction period is shorter
Composite Floors
Composite Floors
combination of precast units and in situ concrete.
precast units that are usually prestressed / reinforced with high yield bars are used to provide the strength of the floor with the smallest depth practicable
At the same time, act as permanent formwork to the in-situ topping that provides the compressive strength required.
Composite floors will act in the same manner as in-situ floor so it can be designed for more complex loadings
Reinforced Concrete Slab / Floor
In- Situ construction Flat Slab Flat Plate Slab Waffle Slab / Honeycomb Floors Beam Floor Slab
FLAT PLATE SLAB
FLAT PLATE SYSTEM
Simple construction Flat plate construction can minimize storey
height (piping, wall cladding, elevators etc) in areas with absolute height restrictions.
Low storey heights due to shallow floor Spans < 20ft (residential & light commercial) Flat ceilings (reduced finishing cost) Have the simplest formwork
Least labor costs Can be applied for short to medium spans
with light loadings Also reduce building weight and effective
area of wind loads
FLAT SLAB
FLAT SLAB
Reduce slab displacementIncreased slab shear resistanceThis system provide relatively a flat ceilings
(reduce finishing cost)Low storey heights due to shallow floorMedium span with light loadingSpans 20 to 40 ftLive load > 100psf (garage, warehouses)
WAFFLE SLAB
WAFFLE SLAB
Used as alternative to an in-site flat slab or a beam and slab suspended floor
This is because it requires less concrete, less reinforcement and can be used to reduce the number of beams and columns required with the resultant savings on foundations.
Moulds are very strong, lightweight & capable of supporting all the normal loads encountered in building works.
Spans >30 ft Use prefabricated standard forms special moulds are placed at certain distance skilled workers are needed & need less steel
SLAB DESIGN
One Way Slab Two Way Slab
- Require less steel
- Few two slabs built in the area of high labor costs
- Suitable for minimizing deflections
One Way Slab
BEAM
Two Way Slab
SLAB FAILURE : CAUSES & EFFECT
TYPES OF SLAB PROBLEM
Cracking Of The Slab
Cold Floor
Damp Or Wet Floor Slab
CRACKING OF THE SLAB : CAUSES
Poor construction techniques and practices Differential / Uneven settlement Inadequate structural strength of concrete Improper placement of reinforcing & mesh
Cracking Of The Slab
Damp or Wet Floor Slab : Causes
Moisture migration through the slab Poor site drainage
Life Is Very Short So Make It Meaningful
Love & Appreciate Your Parents Always