Post on 03-Apr-2018
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BUILDING STRUCTURE ANDCOMPONENTS-PART I
DR CHEAH CHEE BAN
SENIOR LECTURER OF BUILDING TECHNOLOGY
SCHOOL OF HOUSING BUILDING AND PLANNING
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BUILDING STRUCTURES-AN OVERVIEW
Building is a civil engineering infrastructure
which serves as a shelter for human to
execute various activities namely:
Residential
Commercial
Manufacturing
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BUILDING STRUCTURES-AN OVERVIEW
Hence, the function of a
building structural system is to
sustain the self weight of the
building components and the
live load exerted on it byvarious human activities.
The load will be transferred by
various structural elements of
the building from all the floorsand roofto the foundation of
the building.
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BUILDING STRUCTURES-AN OVERVIEW
The various structural
elements which are
responsible for distributionof
building loads are:
Slabs
Beams
Columns
Staircase Walls (Structural and Non-
structural)
Foundation system
(Shallow or deepfoundation)
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BUILDING STRUCTURES-AN OVERVIEW
Eventually the
overall load of the
building will be
transferred to the
sub grade soil of
the proposed site
of the building bythe foundation
system of the
building structure.
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STRUCTURAL SLABS
Slab is a structural
component of a building
main frame which is
designed to sustain panel
load exerted from the
various floor uses.
Structural slabs are indirect contact with the
live load component of a
building.
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STRUCTURAL SLABS
Structural slabs are
usually designed as a
thin plated shell
member with limited
thickness
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STRUCTURAL SLABS
Panel loads are
then transferred
from slabs to
beams, columns or
walls in the form
oftrapezoidal,
triangular, uniformdistributed or
point load
depending on the
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STRUCTURAL SLABS
There are a number ofcommon types of slabs in
a building structure
namely:
1. Spanning slabs between
beams and walls
2. One-way pan joists
3. Two-way reinforced slabsupported directly by
column
4. Two-way flat slab
5. Waffle flat slabs
S S S
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SPANNING SLAB BETWEEN BEAMS AND
WALLS
Description:
Span continuously over
beams and wall supports
Thickness of slab varies
between 75mm-250mm.
Allowable span up to 7.4 m
between supports Widely used in the
construction of reinforced
concrete buildings in
Malaysia.
SPANNING SLAB BETWEEN BEAMS AND
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SPANNING SLAB BETWEEN BEAMS AND
WALLS
Advantages:
Simple formwork (timber or steel) for
fabrication of the slab.
Simple internal reinforcement
arrangement and design.
Well established design method
Allow for higher headroom of building
Disadvantages: High self-weight and inefficient load
transfer ability.
Intensive materials requirements
Not suitable for long span in excess of8 metres
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ONE WAY PAN JOISTS
Description:
Span continuously over
primary beams supports
Thickness of slab usually
fixed at 60mm
Presence of joists spanning
between primary beams.
Joist depth varies between150-510mm
Allowable span up to 12.3
m between supports
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ONE WAY PAN JOISTS
Advantages:
Simple internal reinforcement
arrangement and design.
Well established design method
Allow for longer span of slab
Disadvantages:
Intensive materials requirements
Not suitable for use when there islimited headroom available.
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TWO WAY FLAT PLATE
Description:
Two way reinforced concrete
slab which is supported
directly by column
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TWO WAY FLAT PLATE
Advantages:
Economical design with low formwork
and steel reinforcements requirements
Allow for higher headroom of a
building
Disadvantages:
Low load bearing capacity
Not suitable for use as heavy dutyfloor
High tendency ofpunching shear
failure upon over load.
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TWO WAY FLAT SLAB
Description:
Similar structural arrangement
as two way flat plate.
The presence ofdrop panel on
top of supporting columns is
the distinguishing feature of
flat slab from flat plate.
The drop panel enhances the
shear and bending moment
resisting capacity of the slab
at the column supports
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TWO WAY FLAT SLAB
Advantages:
Higher load bearing capacity as
compared to two way flat plate.
Economical design with low formwork
and steel reinforcements requirements
Allow for higher headroom of a
building
Disadvantages:
Not suitable for use as heavy duty
floor system.
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WAFFLE FLAT SLABS
Description:
Slab is supported by square
grid of closely spacedjoists
The waffle flat slabs are
formed by casting the slab
and joists integrally over
square dome forms
Thickness of slab is 50mm
and supported on grid of
joists with depth up to
400mm.
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WAFFLE FLAT SLABS
Advantages:
Exceptionally high load bearing
capactiy
Allow for very long span of floor up
to 14 metres between supports
Aesthetically appealing structural
form.
Disadvantages:
Material intensive and high cost for
fabrication.
Not suitable for building with
limited headroom
High self-weight and requires very
strong support.
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STRUCTURAL BEAMS
Structural beams are
horizontal members of a
building main frame which act
as the primary supports tostructural slabs.
It is also an intermediate
structural component of abuilding which transfer the
load from the slab to the
structural columns
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STRUCTURAL BEAMS
Under normal service condition,
structural beams are subjected to
combined bending ,shear stresses
and torsion.
Hence, structural beam is classified
as a moment-shear structural
members.
With that the bending moment,shear force and torsion are the
three major parameters considered
in the analysis and design of
structural beams.
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STRUCTURAL BEAMS
There are a few types of
structural beams which are
commonly used in building
construction. They are:
Reinforced concrete beams
Structural steel beams
Pre-stressed concrete beams
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REINFORCED CONCRETE BEAMS
Overview
RC beams which are commonly used in the
Malaysian construction industry is a composite
structural member.
It is fabricated using the combination of structural
concrete and steel reinforcement bars
For common application, reinforced concretebeams has a rectangular cross section.
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REINFORCED CONCRETE BEAMS
Load and stress mitigation mechanism
The load transferred from the slabs to the beams
are in the form ofpoint load or uniform load
The gravity load transferred from the slab onto a
structural beam will be converted into bendingmoment, shear forces and torsion which act
directly on the beam member.
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REINFORCED CONCRETE BEAMS
Load and stress mitigation mechanism
The compressive stress induced bybending moment within the cross
section of a reinforced concrete
beam is resisted by the concrete
matrix of the beam. The tension stress induced by
bending moment within the cross
section of a reinforced concrete
beam is resisted by the steel barsembedded in the concrete matrix.
Meanwhile, the shear stress and
torsion stress component in the
structural member is resisted by
both steel and concrete matrix.
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REINFORCED CONCRETE BEAMS
Analysis and design consideration
There are two basic design of a reinforced
concrete beam namely:
Simply supported beam
Continuously spanning beam
The bending moments and shear forces of a beam
is determined by modeling a beam as a bending
structural member.
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REINFORCED CONCRETE BEAMS
Analysis and design consideration
(Contd)
The design of a reinforced concrete
beam involves the calculation to
determine:
The cross section of concreterequired
The number and size of steel
reinforcements bar required
to sustain the gravity load
transferred to a beam
The design of reinforced concrete
beam is usually performed using the
British Standards BS 8110-Part 1 and
Eurocode 2-EN 1990
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STRUCTURAL STEEL BEAMS
Overview
Structural steel beams is commonly used in the
construction oflong spanning structures such as
factory or storage building
It is also commonly used in countries with activeseismic activities due to its high ductility
performance
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STRUCTURAL STEEL BEAMS
Overview
Structural steel beams is fabricated using hot
rolled structural steel section
For common application, structural steel beam
has standard I-cross section or H cross section.
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STRUCTURAL STEEL BEAMS
Load and stress mitigation mechanism
The load transferred from the slabs to the beams
are in the form ofuniformly distributed load
The gravity load transferred from the slab onto a
structural beam will be converted into bendingmoment, shear forces and torsion which act
directly on the beam member.
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STRUCTURAL STEEL BEAMS
Load and stress mitigation mechanism
Any compression stress and tension stress
induced by the bending moment on steel beam
will be resisted by both flange and web of the
steel beam Meanwhile, the shear stress and torsion stress
component in the structural steel member is
resisted mainly by web of the beam
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STRUCTURAL STEEL BEAMS
Analysis and design consideration
Structural steel beam are usually designed as a
single span simply supported structural member.
The bending moments and shear forces of a beam
is determined by modeling a beam as a bending
structural member.
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STRUCTURAL STEEL BEAMS
Analysis and design
consideration (Contd)
The design of a structural steel beam
involves the calculation to determinethe size of steel cross section and
joint required to sustain the gravity
load transferred to a beam
The design of structural steel beam isusually performed using the British
Standards BS 5950-2000
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PRESTRESSED CONCRETE BEAM
Overview
Pre-stressed concrete beam is commonly used in
the construction ofvery long spanning structures
(span >20 metres) such as factory, storage buildingor bridges.
Besides, it has an extremely high bending load
bearing capacity.
S SS CONC A
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PRESTRESSED CONCRETE BEAM
Overview
Pre-stressed concrete beams is fabricated using
the combination of high tension yield cable (Grade
>1200MPa) and high strength concrete matrix(Grade >70MPa).
Tensioning force is induced within the cable
placed in the beam member using a high capacity
hydraulic jack.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Load and stress mitigation mechanism
The load transferred from the slabs to the beams
are in the form ofuniformly distributed load
The gravity load transferred from the slab onto a
prestressed concrete beam will be converted intobending moment, shear forces and torsion which
act directly on the beam member.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Load and stress
mitigation mechanism The tension stress induced by
the bending moment on pre-
stressed concrete beam will
be transformed intocompression stress by the
high tension force cable
embedded in the concrete
matrix
Meanwhile, the shear stress
and torsion stress component
in the structural steel
member is resisted mainly by
steel reinforcements providedin the beam.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Analysis and design consideration
Prestressed concrete beam are usually designed
as a single span simply supported structural
member. The bending moments and shear forces of a beam
is determined by modeling a beam as a bending
structural member.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Analysis and design consideration
There are two forms of prestressed concrete
namely:
Pre-tensioning beam member
Post-tensioning beam member
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Analysis and design
consideration
Pre-tensioning:
Tensioning force of the
cable is induced beforethe placement of
concrete.
Post-tensioning:
Tensioning force of thecable is induced after
the placement and
hardening of concrete.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Analysis and design
consideration (Contd)
The design of a prestressed
concrete beam involves thecalculation to determine
the size of concrete cross section,
number ofhigh tension cable and
the tensioning force of cable
required to sustain the gravity
load transferred to a beam
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
Analysis and design consideration (Contd)
The tensioning force induced in the steel is usually
in the range of 50-500 tonnes.
The design of reinforced concrete beam is usuallyperformed using the British Standards BS 8110-
Part 2.
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
CYBERJAYA FLYOVER COLLAPSED:WHAT
ACTUALLY HAPPENED?
PRESTRESSED CONCRETE BEAM
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PRESTRESSED CONCRETE BEAM
SPECULATIONS.....
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Presented by
DR CHEAH CHEE BAN | SENIOR LECTURER, SCHOOL OFHOUSING BUILDING AND PLANNING