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Chapter 4
1. BACHELOR OF QUANTITY SURVEYING
(HONS)
BLD 60104 CONSTRUCTION TECHNOLOGY 1
By Azrina Md Yaakob
Azrina.MdYaakob@taylors.edu.my
CHAPTER 4
CONCRETE FRAMED BUILDINGS
2. CONCRETE
Mixture of cement, fine
& coarse aggregate &
water
Basic construction:
a) Concrete
b) Formwork
c) Reinforcement
FRAMED
Consists of:
a) upright load bearing
members such as posts
in timber
b) columns in concrete
c) stanchions in steel
which are arranged at the
corners of the square or
rectangular base
Transfer loads of heavy
structure plus any
imposed loads via the
f r a m e s t r u c t u r e
members to a suitable
lower ground
BUILDING
R e s i d e n t i a l ,
Commercial, Offices,
Etc
1.0 BASIC DEFINITION
4. 1.1 CONCRETE
• Increases its strength during curing / hardening period
• Portland cement is used –28days
• Nominal max sizes of aggregates: 40, 20, 14 and 10mm;
5mm is for precast products
• Grade 7 & 10 -plain unreinforced concrete
• Grade 15 & 30 –RC with lightweight aggregates
• Grade 25 –RC with dense aggregates
• Grade 30 to 50 –pre-stressed concrete
5. 1.2 REINFORCEMENT
Requirements:
• Capable of achieving tensile strength without any undue strain
• A material can be easily bend to any required shape
• Surface must be capable of developing adequate bond between the
concrete & reinforcement
• Reasonable cost & acceptable to overall design concept
• Steel in the form of bars
• mild steel (R) & high yield (T)
• nominal sizes: 6, 8, 10, 12, 16, 20, 25, 32mm
6. 1.3 FABRIC REINFORCEMENT
• Structural members that require only small area of reinforcement
• Can be reinforced by steel fabric, which can be supplied by sheets /
rolls
• Factory-made by welding
• Sheets: 4800mm x 2400mm
• Rolls: 48.00m & 72.00m with a common width of 2.40m
7. 1.4 FORMWORK
• A mould / box into which wet concrete can be poured so that it will flow
& finally set to the inner profile of the box
• Requirements:
• Strong enough to support the load of wet concrete
• Must be accurately set out
• Have grout-tight joints –grout leakage can cause honeycombing of the
surface
• Designed to be the max size that can be easily handled by hand &
mechanical lifting device
• Moisture content btw 15 –20%
Bad Formwork Design :
Leakage which cause
honeycombing
9. 1.4.1 FOUNDATION FORMWORK
There are 2 types of foundation formwork:
1. Permanent formwork
2. Traditional timber formwork
Benefits of using permanent formwork:
Ø Less concrete waste
Ø Requires less excavation than traditional wood planks
Ø Easily transported because of the light weights
Ø No skilled labours are needed
Benefits of using traditional timber formwork:
Ø It can be reused
Ø Cheaper production cost
Ø Higher availability than steel
Ø Easy to work by using hammer and nails
13. 1.4.3 BEAM FORMWORK
• A beam form consists of a three-sided box which is supported by
cross-members called headtrees.
• Soffit board should be fixed inside the beam sides so that latter can
be removed. This also can speed up the hardening process and also
release the formwork for re-use.
14. 1.4.4 SLAB FORMWORK
There is four type of slab formwork:
1. Timber beam slab formwork
2. Traditional slab formwork
3. Metal beam slab formwork
4. Modular slab formwork
Metal
beam
slab
fwk.
Timber
beam
slab
fwk.
Modular
slab
fwk.
Schema7c
sketch
of
tradi7onal
fwk.
15. 1.4.4.1 TRADITIONAL SLAB FORMWORK
• Consists of supports out of lumber or young tree trunks, that support tows of
stringers
• Assembled roughly to 2 meters apart, depending the thickness of slab
• Between these stringers, joists are positioned roughly 30cm apart upon which
boards or plywood are placed.
• The stringers and joists are usually 4 by 4 inch or 4 by 6 inch lumber
16. 1.4.4.2 TIMBER BEAM SLAB FORMWORK
• Similar to the traditional method
• But stringers and joist are replaced with engineered wood beams
• Supports are replaced with metal props
• This method more systematic and reusable
17. 1.4.4.3 METAL BEAM SLAB FORMWORK
• Similar to traditional method
• But stringers and joist are replaced with aluminium forming systems or steel
beams
• Supports are replaced with metal props
• More systematic and reusable
18. 1.4.4.4 MODULAR SLAB FORMWORK
• These systems consist of prefabricated timber, steel or aluminum
beams and formwork modules
• Modules are often no larger than 1 to 2 meter in size
• Beams and formwork are typically set by hand and pinned, clipped, or
screwed together
20. 1.5.1 STUMP
• A short column constructed on top of the pad foundation / pile
cap to support ground beam & column above
• To transfer the load of a building onto the pad foundation / pile
cap
• To raise ground beam & ground floor slab to the required
height above GL
21.
22. 1.5.2 BEAMS
• Supporting walls, joists, etc., at or near ground level, itself either
resting directly upon the ground or supported at both ends by piers.
• Vary in their complexity of design & reinforcement depends on
loading
• Erected over columns or piers taken into the soil
• Transfer their loadings to columns
• When erecting them, the piers must be already cast in the ground
23. 1.5.2.1 BEAM CONSTRUCTION PROCESS
Clearing the ground
Blinding layer
Reinforcements are then tied and bent
separately; carried and laid over the columns
and blinding
Formwork erected to sides
Concrete is prepared and poured
25. 1.5.3 COLUMNS
• Constructed from either plain concrete (1:3:6) / reinforced concrete
(1:2:4)
• Vertical structural element that transmits, through compression, the
weight of the structure above to other structural elements below
• To support beams or arches on which the upper parts of walls or
ceilings rest
• Columns must be properly located, and the choice of a steel beam or
wood beams
29. 1.5.4 FLOOR
Functions of Ground Floor
• Withstand load imposed upon them, dead & live load
• Prevent the growth of greens inside the building by concrete over-site
• Prevent damp penetrating the building –damp proof membrane
• To be durable so to reduce the amount of maintenance / replacement
work to a min
• Provide acceptable finish which will meet the needs of users
30. Functions of Upper Floor
• Support their own weight, ceilings & superimposed
loads
• Restrict the passage of fire; for high-rise building
• Restrict transmission of sound from 1 floor to another
• Durability
• Bridge the specific span economically & be capable of
fairly quick erection
• Accommodate services
• Provide acceptable finish which will meet the needs of
users
31. Floor Slab
• The formwork for floor beam & floor slab is constructed
together
• Reinforcement for floor slab tied to beam reinforcement
34. a) Hardcore
• To fill hollows & to raise the finished level of an over-site concrete
slab after removal of turf
• Provide a firm working surface & prevent contamination of the lower
part of wet concrete
• Reduce the amount of rising ground moisture
• hard, durable & chemically inert; will not attack concrete & mortar;
readily be placed in in a compact & dense condition
• 100-150mm thick
b) Blinding
• To even-off the surface of hardcore if a damp-proof membrane is to
be placed under concrete bed
• A layer of sand 25 –50mm thick
35. c) Damp Proof Membrane
• To prevent dampness getting through a ground bearing concrete floor should be
protected by an impervious layer, usually a 1200 gauge (0.3mm) heavy duty
polythene damp-proof membrane.
• The DPM can be positioned either on the sand blinding or on the concrete slab.
• Joints in a Polythene DPM should be welted or taped and should overlap by at
least 300mm.
• The DPM must be linked with the DPC in the walls, to ensure that the entire
interior of the building is protected from moisture by a continuous, impervious
barrier.
36. d) Concrete Floor Slab
• A typical concrete mix for a ground bearing slab is 1:2:4 mix.
• The floor slab is usually placed over the DPM
• The floor slab should not be less than 100mm thick.
• Ensure all the services and ducts running under the floor are installed
and tested before pouring the slab.
• If required, the concrete slab may be reinforced with a layer of steel
mesh
• Once the concrete slab has been poured, it can be temped with a
heavy beam to remove air and surplus water and ensure a level
surface.
• The concrete slab should be left to dry out for around two to three days
39. 1.5.4.3 FLOOR FINISHES
Factors to be considered during choosing a right floor finishes:
• Durability –avoid premature replacement with extra cost &
inconvenience
• Function
• Resistance to wear –resistance to indentation as floor has to withstand
heavy furniture, fittings & equipment; resistance to abrasion in
buildings subject to movable equipment
• Economy –initial & maintenance cost
• Non-slip qualities –bathroom & kitchen
• Appearance –wood blocks & strip flooring
40. 1.6 ROOF BEAM
• A load-bearing member in the roof structure.
• Member that span across the openings & support structure or
loading above them
• Material : timber, steel & reinforced concrete
• Purlin act as beam, reducing the span of the rafter enabling an
economic section to be used
41.
42.
43. TUTORIAL 4 (A)
• In a table form, explain the type of materials available
for formwork.
• Item to be included in the tables are:
ü Suitability
ü Advantages
ü Disadvantages
ü Cost
Requirements:
You should prepare the table form which need to be presented.
Please state your name, student ID and title. (Group)
44. • In a table form, explain the type of materials available
for floor finishes.
• Item to be included in the tables are:
ü Suitability
ü Advantages
ü Disadvantages
ü Cost
Requirements:
You should prepare the table form which need to be presented.
Please state your name, student ID and title. (Group)
TUTORIAL 4 (B)
