TOPIC 1.2 FORCES ON CIVIL ENGINEERING PROJECT BY : NOR AZAH BINTI AZIZ KOLEJ MATRIKULASI TEKNIKAL KEDAH.
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Slide 1
TOPIC 1.2
FORCES ON
CIVIL ENGINEERING PROJECT
BY :
NOR AZAH BINTI AZIZ
KOLEJ MATRIKULASI TEKNIKAL KEDAH
Slide 2
FORCES ON
CIVIL ENGINEERING PROJECT
LEARNING OUTCOMES :
a) Identify and describe the engineering forces due to;
• Physical forces
Dead load, traffic loads, imposed loads, hydrostatic/ water
pressure, lateral earth pressure
-
• Environmental forces
Wind, earthquake, waves, explosion, flood, temperature and
pollutants
-
b) Identify and describe the engineering forces based
on chosen case project.
Slide 3
INTRODUCTION
In any building design, the strength and
stability of an overall building and its individual
components must be considered.
This involves structural calculations to work
out the effects of all the forces acting on any
component in the building and on the
building overall.
To do this we need to resolve the forces in
the system to see what the overall effects
are likely to be.
Slide 4
INTRODUCTION
An overview of the many different forces acting on a building.
Slide 5
INTRODUCTION
A summary of all the forces acting on the building.
The dotted arrow is the resultant force,
a force representing the overall effect of the loads.
Slide 6
INTRODUCTION
Structural Engineering
• What does a Structural Engineer do?
A Structural Engineer designs the structural systems
and structural elements in buildings, bridges,
stadiums, tunnels, and other civil engineering
works
Design:
process of determining location, material, and size
of structural elements to resist forces acting in a
structure
Slide 7
Examples of Typical Structures
Slide 8
TYPES OF PHYSICAL FORCES
Dead Load/
self weight
Live Load /
Imposed load
Traffic Load
Hydrostatic
Forces /
Water Pressure
Lateral earth
Pressure
Slide 9
i) DEAD LOAD
Dead loads are permanent or stationary loads
which are transferred to structure throughout
the life span.
Dead load is primarily due to
self weight of structural members
permanent architectural component such
as exterior cladding, partitions and ceilings
equipment and static machinery when
permanent fixtures
Slide 10
A Simply Supported Beam
Loads
Compression
Tension
Slide 11
ii) LIVE LOAD/IMPOSED LOAD
The total of all moving and variable loads that may be placed upon a
building or home
Load that acts on structural component.
Loads produced by use and occupancy of the building structure
including weights of movable partitions or furniture etc.
These load are more difficult to determine accurately.
Estimates done on standard codes of practice or past
experience.
Slide 12
EXAMPLE
Towers: Live and Dead Loads
Towers serve many purposes. Radio, TV and wireless
communication signals are transmitted from towers.
Forest rangers keep a vigilant eye peeled for signs of
forest fires from observation towers. Skyscrapers
serve an important role in the world’s urban areas.
Like other structures, towers are subjected to dead
and live loads. In the case of a skyscraper, dead loads
are comprised of steel columns and beams, concrete,
and glass – the weight of the structure itself. Live
loads include the people milling about on the floors
and ascending the elevators; plus furniture, materials,
and goods that move into the building.
Another important live load acting on a skyscraper is
the force of wind blowing against the exterior
surfaces. Because the buildings have an enormous
amount of surface area, the force of wind on a
skyscraper can be extremely powerful.
Slide 13
ii) TRAFFIC LOAD
Traffic load is the average number ofvehicles two-way
passing a specific point in a 24-hour period, normally
measured throughout a year
The standard measurement for vehicle traffic load on a section
of road, and the basis for most decisions regarding transport
planning.
Road authorities have norms based on traffic load with
decisions to expand road capacity.
Slide 14
Traffic Force Transfer Example
- Bridge
8,000 lb
32,000 lb
15 ft
45 ft
30 ft
30 ft
L = 60 ft
22,000 lb*
*Front axle: 8,000 lb x 45/60 = 6,000 lb
Rear axle: 32,000 lb x 30/60 = 16,000 lb
18,000 lb**
**Front axle: 8,000 lb x 15/60 = 2,000 lb
Rear axle: 32,000 lb x 30/60 = 16,000 lb
Slide 15
ii) LATERAL EARTH PRESSURE
Lateral earth pressure is the pressure that soil exerts in the
horizontal plane.
The common applications of lateral earth pressure theory are
for :
i) the design of ground engineering structures
such as retaining walls, basements, tunnels
ii) to determine the friction on the sides of deep
foundation
Slide 16
Lateral Support
In geotechnical engineering, it is often
necessary to prevent lateral soil movements.
Tie rod
Anchor
Sheet pile
Cantilever
retaining wall
Braced
excavation
Anchored sheet
pile
Slide 17
Lateral Support
We have to estimate the lateral soil pressures
acting on these structures, to be able to design
them.
Gravity
Retaining
wall
Soil
nailing
Reinforced earth
wall
Slide 18
Soil Nailing
Slide 19
Lateral Support
Reinforced earth walls are increasingly
becoming popular.
geosynthetics
Slide 20
Lateral Support
Crib Wall have been used in Queensland.
Good drainage & allow plant growth.
Looks good.
Interlocking
stretchers
and headers
filled with
soil
Slide 21
Lateral Support
Reinforced earth walls are increasingly becoming
popular.
geosynthetics
22
Slide 22
Lateral Support
Crib walls have been used in Queensland.
filled with
soil
Good drainage & allow plant growth.
Looks good.
Interlocking
stretchers
and headers
23
Slide 23
Retaining Walls - Applications
Road
Train
24
Slide 24
Retaining Walls - Applications
highway
25
Slide 25
Retaining Walls - Applications
High-rise
building
basement wall
26
Slide 26
Gravity Retaining Walls
cement mortar
plain concrete or
stone masonry
cobbles
They rely on their self weight
to support the backfill
27
Slide 27
Cantilever Retaining Walls
Reinforced;
smaller
section than
gravity walls
They act like vertical
cantilever, fixed to the ground
28
Slide 28
Soil exerts pressures on retaining
structures
Slide 29
Slide 30
ii) HYDROSTATIC PRESSURE/
WATER PRESSURE
In a fluid at rest, the weight of the liquidwill create a pressure
on the surface of a body.
This pressure is defined as the hydrostatic pressure.
Its depend on density of the liquid and depth.
Normally consider for marine structure and
dam structure.
Slide 31
Dam Structure
Arch Dam
Cross Section
Slide 32
Environmental Forces
Forces that acting to
engineering structure due to
environmental factor
33
Slide 33
i)
Wind Load
Wind Load
What it means
• positive or negative
pressures exerted on a
house when it obstructs
the flow of moving air.
• generally act
perpendicular to the
surfaces of the building.
34
Slide 34
i)
Wind Load
What it affects
• The significance of the load
varies depending on the
geographic location of the
house, its height, and its roof
pitch.
• have the most significant
impact on roof framing,
overhangs, and large
openings, especially those
near building corners.
• On a larger scale, shearresisting elements, like the
roof, floor framing, and
sheathed wall segments (shear
walls), are affected by wind
loads.
• Typically, building are
designed to resist a strong
wind a very long return
period, e.g 50 yrs or more.
• The design wind speed is
determined from historical
record to protect future
extreme wind speeds.
35
Slide 35
i)
Wind Load
36
Slide 36
37
Slide 37
38
Slide 38
39
Slide 39
ii) Earthquake
Also known as quake or tremor.
Is the result of sudden release of energy in the earth crust that
causes seismic waves.
Measured with a seismometer
The seismicity @ seismic activity of an area refers to the frequency, type n
size earthquake experienced over a period of time.
At the earth’s surface, earthquake manifest themselves by
shaking and sometimes displacing the ground.
40
Slide 40
ii) Earthquake
At the earth’s surface, earthquake manifest themselves by
shaking and sometimes displacing the ground.
When a large earthquake epicenter is located offshore, the
seabed sometimes suffer sufficient displacement to cause a
tsunami
The shaking in earthquake can also trigger landslide and
occasionally volcanic activity
41
Slide 41
42
Slide 42
iii) Waves Load
A waves is a disturbance that propagates.
The impact of a pulsed or wavelike load to an
engineering stucture.
Commonly used in the analysis of offshore structure,
piping and an engineering platform.
43
Slide 43
44
Slide 44
45
Slide 45
iv) Flood
Flood is an overflow or accumulation of an expanse
of water that submerges land.
46
Slide 46
47
Slide 47
48
Slide 48
49
Slide 49
50
Slide 50
51
Slide 51
52
Slide 52
53
Slide 53
54
TOPIC 1.2
FORCES ON
CIVIL ENGINEERING PROJECT
BY :
NOR AZAH BINTI AZIZ
KOLEJ MATRIKULASI TEKNIKAL KEDAH
Slide 2
FORCES ON
CIVIL ENGINEERING PROJECT
LEARNING OUTCOMES :
a) Identify and describe the engineering forces due to;
• Physical forces
Dead load, traffic loads, imposed loads, hydrostatic/ water
pressure, lateral earth pressure
-
• Environmental forces
Wind, earthquake, waves, explosion, flood, temperature and
pollutants
-
b) Identify and describe the engineering forces based
on chosen case project.
Slide 3
INTRODUCTION
In any building design, the strength and
stability of an overall building and its individual
components must be considered.
This involves structural calculations to work
out the effects of all the forces acting on any
component in the building and on the
building overall.
To do this we need to resolve the forces in
the system to see what the overall effects
are likely to be.
Slide 4
INTRODUCTION
An overview of the many different forces acting on a building.
Slide 5
INTRODUCTION
A summary of all the forces acting on the building.
The dotted arrow is the resultant force,
a force representing the overall effect of the loads.
Slide 6
INTRODUCTION
Structural Engineering
• What does a Structural Engineer do?
A Structural Engineer designs the structural systems
and structural elements in buildings, bridges,
stadiums, tunnels, and other civil engineering
works
Design:
process of determining location, material, and size
of structural elements to resist forces acting in a
structure
Slide 7
Examples of Typical Structures
Slide 8
TYPES OF PHYSICAL FORCES
Dead Load/
self weight
Live Load /
Imposed load
Traffic Load
Hydrostatic
Forces /
Water Pressure
Lateral earth
Pressure
Slide 9
i) DEAD LOAD
Dead loads are permanent or stationary loads
which are transferred to structure throughout
the life span.
Dead load is primarily due to
self weight of structural members
permanent architectural component such
as exterior cladding, partitions and ceilings
equipment and static machinery when
permanent fixtures
Slide 10
A Simply Supported Beam
Loads
Compression
Tension
Slide 11
ii) LIVE LOAD/IMPOSED LOAD
The total of all moving and variable loads that may be placed upon a
building or home
Load that acts on structural component.
Loads produced by use and occupancy of the building structure
including weights of movable partitions or furniture etc.
These load are more difficult to determine accurately.
Estimates done on standard codes of practice or past
experience.
Slide 12
EXAMPLE
Towers: Live and Dead Loads
Towers serve many purposes. Radio, TV and wireless
communication signals are transmitted from towers.
Forest rangers keep a vigilant eye peeled for signs of
forest fires from observation towers. Skyscrapers
serve an important role in the world’s urban areas.
Like other structures, towers are subjected to dead
and live loads. In the case of a skyscraper, dead loads
are comprised of steel columns and beams, concrete,
and glass – the weight of the structure itself. Live
loads include the people milling about on the floors
and ascending the elevators; plus furniture, materials,
and goods that move into the building.
Another important live load acting on a skyscraper is
the force of wind blowing against the exterior
surfaces. Because the buildings have an enormous
amount of surface area, the force of wind on a
skyscraper can be extremely powerful.
Slide 13
ii) TRAFFIC LOAD
Traffic load is the average number ofvehicles two-way
passing a specific point in a 24-hour period, normally
measured throughout a year
The standard measurement for vehicle traffic load on a section
of road, and the basis for most decisions regarding transport
planning.
Road authorities have norms based on traffic load with
decisions to expand road capacity.
Slide 14
Traffic Force Transfer Example
- Bridge
8,000 lb
32,000 lb
15 ft
45 ft
30 ft
30 ft
L = 60 ft
22,000 lb*
*Front axle: 8,000 lb x 45/60 = 6,000 lb
Rear axle: 32,000 lb x 30/60 = 16,000 lb
18,000 lb**
**Front axle: 8,000 lb x 15/60 = 2,000 lb
Rear axle: 32,000 lb x 30/60 = 16,000 lb
Slide 15
ii) LATERAL EARTH PRESSURE
Lateral earth pressure is the pressure that soil exerts in the
horizontal plane.
The common applications of lateral earth pressure theory are
for :
i) the design of ground engineering structures
such as retaining walls, basements, tunnels
ii) to determine the friction on the sides of deep
foundation
Slide 16
Lateral Support
In geotechnical engineering, it is often
necessary to prevent lateral soil movements.
Tie rod
Anchor
Sheet pile
Cantilever
retaining wall
Braced
excavation
Anchored sheet
pile
Slide 17
Lateral Support
We have to estimate the lateral soil pressures
acting on these structures, to be able to design
them.
Gravity
Retaining
wall
Soil
nailing
Reinforced earth
wall
Slide 18
Soil Nailing
Slide 19
Lateral Support
Reinforced earth walls are increasingly
becoming popular.
geosynthetics
Slide 20
Lateral Support
Crib Wall have been used in Queensland.
Good drainage & allow plant growth.
Looks good.
Interlocking
stretchers
and headers
filled with
soil
Slide 21
Lateral Support
Reinforced earth walls are increasingly becoming
popular.
geosynthetics
22
Slide 22
Lateral Support
Crib walls have been used in Queensland.
filled with
soil
Good drainage & allow plant growth.
Looks good.
Interlocking
stretchers
and headers
23
Slide 23
Retaining Walls - Applications
Road
Train
24
Slide 24
Retaining Walls - Applications
highway
25
Slide 25
Retaining Walls - Applications
High-rise
building
basement wall
26
Slide 26
Gravity Retaining Walls
cement mortar
plain concrete or
stone masonry
cobbles
They rely on their self weight
to support the backfill
27
Slide 27
Cantilever Retaining Walls
Reinforced;
smaller
section than
gravity walls
They act like vertical
cantilever, fixed to the ground
28
Slide 28
Soil exerts pressures on retaining
structures
Slide 29
Slide 30
ii) HYDROSTATIC PRESSURE/
WATER PRESSURE
In a fluid at rest, the weight of the liquidwill create a pressure
on the surface of a body.
This pressure is defined as the hydrostatic pressure.
Its depend on density of the liquid and depth.
Normally consider for marine structure and
dam structure.
Slide 31
Dam Structure
Arch Dam
Cross Section
Slide 32
Environmental Forces
Forces that acting to
engineering structure due to
environmental factor
33
Slide 33
i)
Wind Load
Wind Load
What it means
• positive or negative
pressures exerted on a
house when it obstructs
the flow of moving air.
• generally act
perpendicular to the
surfaces of the building.
34
Slide 34
i)
Wind Load
What it affects
• The significance of the load
varies depending on the
geographic location of the
house, its height, and its roof
pitch.
• have the most significant
impact on roof framing,
overhangs, and large
openings, especially those
near building corners.
• On a larger scale, shearresisting elements, like the
roof, floor framing, and
sheathed wall segments (shear
walls), are affected by wind
loads.
• Typically, building are
designed to resist a strong
wind a very long return
period, e.g 50 yrs or more.
• The design wind speed is
determined from historical
record to protect future
extreme wind speeds.
35
Slide 35
i)
Wind Load
36
Slide 36
37
Slide 37
38
Slide 38
39
Slide 39
ii) Earthquake
Also known as quake or tremor.
Is the result of sudden release of energy in the earth crust that
causes seismic waves.
Measured with a seismometer
The seismicity @ seismic activity of an area refers to the frequency, type n
size earthquake experienced over a period of time.
At the earth’s surface, earthquake manifest themselves by
shaking and sometimes displacing the ground.
40
Slide 40
ii) Earthquake
At the earth’s surface, earthquake manifest themselves by
shaking and sometimes displacing the ground.
When a large earthquake epicenter is located offshore, the
seabed sometimes suffer sufficient displacement to cause a
tsunami
The shaking in earthquake can also trigger landslide and
occasionally volcanic activity
41
Slide 41
42
Slide 42
iii) Waves Load
A waves is a disturbance that propagates.
The impact of a pulsed or wavelike load to an
engineering stucture.
Commonly used in the analysis of offshore structure,
piping and an engineering platform.
43
Slide 43
44
Slide 44
45
Slide 45
iv) Flood
Flood is an overflow or accumulation of an expanse
of water that submerges land.
46
Slide 46
47
Slide 47
48
Slide 48
49
Slide 49
50
Slide 50
51
Slide 51
52
Slide 52
53
Slide 53
54