Structural+Element

8/12/2019 Structural+Element

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PREPARED BY :

NOR AZAH BINTI AZIZ

KOLEJ MATRIKULASI TEKNIKAL KEDAH

2.0 ANALYSIS AND DESIGN2.2 STRUCTURAL ELEMENTS



Load Paths

• The load path is simply the direction in

which each consecutive load will pass

through connected members.

• The sequence commences at the highest point

of the structure working all the way down to

the footing system, ultimately transferring the total

load of the structure to the foundation.



Load Paths

• Ultimately, the lowest structural member must

be strong enough to support all members above it.

• This is why engineers often design the uppermostmembers first and progressively work their way

down the structure following the load path.



RAFTER

PURLIN

GROUND SLAB

STUMP

FOUNDATION

COLUMN

ROOF BEAM

ELEVATED

SLAB

ROOF SHEET

GROUND BEAM WALL

Load analysis distribution and path



Load Path Components in a Concrete

structure• Part of the load

path in a typical

multi-storey

reinforced concrete

structure is made upof the following

components.

MAIN BEAMS

COLUMN

FLOOR SLABS

SECONDARY

BEAMS



Load Path in a Domestic Structure

The direction that loads are transferred through

a structure is important and must be identified.

A simple domestic structure works on similar

principles as a large concrete structure althoughthe components are different:

- the foundation supports the footings

- the footings support the flooring structure which

consist of bearers, joists and flooring- the stud walls and bracing transfer their load to the flooring

- the roof trusses support the battens which support

the roof cladding and this load is transferred to the walls.



Load Path

• A diagram shows theframing of the roof, wall,

floor, footing and

foundation of a building.

•

The load of the path isshown in the diagram.

ROOF

WALL

FLOOR

FOOTING

FOUNDATION



Load Path

STRUCTURAL

COMPONENTLOAD PATH

Roof Roof load are transfer to roof

beamWall Wall load is transfer to beam

Floor Slab Carry direct applied load and

transfer it to beam

Beam Carry load from floor slab and

transfer it to column

Column Carry load from beam and

transfer it to foundation

Foundation Carry and distribute building

load to soil beneath



Nature of Load- Point Load

• A point load

- often abbreviated to P or L

- is a load acting at a single point.- sometimes called a concentrated load.

• Example;

- Roof truss supported on a top plate

- As the contact area of a truss on the top plate is small,

the load is assumed to be concentrated at a point.



Nature of Load- Point Load

• A diagram shows a plank of timber

appearing horizontally above a

roof truss.

• At the end of the plank is an arrow

showing the information P or L

units kN.

• On either side of the roof truss is a

top plate.

• Where the top plate and roof truss

intersects is a an arrow indicatingP or L.

N t f L d U if l Di t ib t d



Nature of Load- Uniformly Distributed

Load

• A uniformly distributed load (UDL)

- is a load that is evenly spread along a length

or across an area.

• For example, the loads supported by a

typical beam include:

• the beam’s own weight

• the weight of the floor slab it is supporting

• the live load supported by the floor slab.

N t f L d U if l Di t ib t d



Nature of Load- Uniformly Distributed

Load

• These loads are consistent along the entire

length of the beam.

• The load may be represented as ;

i) rate per linear metre (kN/m) for beams

ii) rate per square metre (kN/m2) for slabs.

t t t



ature o oa - n orm y str ute

Load

•

A diagram shows a beam withthe load distributed all along

its length.

• The load is labelled UDL with

units shown as kN/m or

kN/m2.

• A reinforced concrete beam is

displayed and labelled with

UDL equal to 4.3 kN/m.

• A reinforced concrete slab is

displayed and labelled 2.7

kN/m2.

N t f L d U if l V i



Nature of Load- Uniformly Varying

Load

• A uniformly varying load

- is a load that is distributed along the length

of a linear element such as a beam,

but instead of the load being evenly spread itvaries in a linear fashion.

• Example ; Retaining wall.

- is designed to hold back earth, which exerts a

horizontal force on the back of the retaining wall.

t



ature o oa - n orm y ary ng

Load

• A diagram shows a vertical

section through a retaining

wall.

• The retaining wall is in the

shape of an upside down

‘T’. The earth to the left of

the wall is labelled ‘retained

earth pushes horizontally at

back of wall’.

t



ature o oa - n orm y ary ng

Load • A diagram shows a symbolic

representation of a uniformlyvarying load on a retaining wall.

• This shows a number of arrowspointing to the right. The lengthof these arrows indicates the

strength of the load on the wallat different heights.

• The load is smallest at the top ofthe wall and greatest at the baseof the wall.

• A right angled triangle is drawnaround these arrows to furtherillustrate this point.



• Moments are a

measure of the turning

effect of a force around

a specified turning pointor pivot.

• A moment is a force

times a distance. The

unit used to measure amoment is newton

metres (Nm).

Nature of Load- Moments



M = F x d

M = 10 N x 5 m

M = 50 Nm

Note that the units are Nm (newton metres)

not N/m (newtons per metre).




• The direction of a moment is opposite

to the direction of the force




•The convention is that:

• clockwise moments are positive

• anti-clockwise moments are negative.




MAIN BEAMS

ARE SUPPORTED BY COLUMN

BACK



COLUMN

ARE ARRANGED IN A GRID PATTERN

BACK



SLABS

ARE SUPPORTED BY THE MAIN BEAMS

BACK



SECONDARY BEAMS

ARE SUPPORTED BYTHE MAIN BEAMS

BACK



Roof

The roof load path flows

down through the walls tothe foundation.

BACK



Wall

The wall load path flows

down through the floor tothe foundation.

BACK



Floor

The floor load path flows

down through the footingto the foundation.

BACK



Footing

The footing load path

flows down through tothe foundation.

BACK



Foundation

The foundation

supports the footings.

BACK

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