1. Roads and Bridges
Construction Methods & resources
by:
1
Jihad Daniel

2. Types of Roads
• Various types of roads are in use
around the world. Roads range in
size from private driveways, to
the stereotypical two-lane
highways, to high capacity dual
carriageway routes, such as
freeways and motorways.
• In addition, depending
on their types, roads may
have different types of
junction. 2

3. Types of Junctions
Bridge
interchange
Intersection
Flyover and
underpasses Junctions at
grade
Interchange
at
grade
3

4. Types of Junctions
• Interchange at grade
• Intersection at grade
4

5. Types of Junctions
• Flyovers
• Bridge interchange
5

6. Road Structure
• Cross section of a road: main
road situated outside towns and
cities.
• Platform: horizontal surface raised
above the surrounding ground.
• Shoulder: space between the
roadway and the ditch.
• Median strip: separation between
two carriageway.
• Wearing course: surface layer of
the road (asphalt).
• Carriageway: central part reserved
for vehicle traffic.
• Ditch: channel that carries away
water. 6

7. Road Structure
• Subgrade: upper surface of
platform.
(this is valid in a cut section)
• In a Fill Section, the
embankment constitute the
platform and the subgrade.
• Subbase: lower surface of a road
structure.
• Base course: main foundation
element (bituminous / granular).
• Wearing Course (Bituminous in
general)
7

8. Road Profile
• The right of way ground formation maybe, as the road profile requires,
natural ground, cut or fill. In case of fill, ground formation is filled in layers
to comply with the profile. The work is called embankment.
• Embankment is made in layers with thickness varying from 20 to 40 cm
depending on the material used.
• In case of cut this could be open cut or tunnel.
8

9. Materials
Selected Crushed Asphaltic
Roads
fill aggregate concrete
9

10. Road Furniture and
Incidental Works
Road furniture refers to
all fixtures in the road
reserve. The term
includes fixtures on the
road surface such as:
- Signs,
- Markings,
- Safety barriers,
- Road studs, etc.
10

11. Method of Construction
The system is based on a monthly output of
major work items using the minimum
equipment considered necessary to carry out the
work during a month of 25 working days, each
day being 8 working hours.
11

12. Road works planning
criteria
• Planning road works, as a first step, depends on the
extent of earthmoving quantities.
• Generally, the most driving is the fill making the
embankment, especially for the case of high
embankments.
• The basic equipment is as follows:
12

13. Fill
From Common Excavation of Borrow Excavation:
Basic Equipment for One Work Team
No. of Items Item
6 Dump Trucks (8 m3), 12 to 15 Tons
1 Front-end Loader (2m3 bucket)
1 Motor Grader (150 hp)
2 Water Trucks (12 m3)
1 Vibratory Roller (40 kw)
1 Farm Tractor (if roller is not self-
propelled)
13

14. Cut & Fill
From Common Excavation or Borrow Excavation:
Basic Equipment for Two Work Teams
No. of Items Item
12 Dump Trucks (8 m3)
2 Front-end Loader (2 m3)
2 Bulldozers (200-300 hp)
3 Motor Grader (150 hp)
2 Vibratory Rollers (40 kw)
6 Water Tanker Trucks (12,000 liters)
2 Farm Tractors (if roller is not self-
propelled)
1 Pneumatic Roller (25 mg)
14

15. Production rates
Assuming:
Number of dump trucks =12
Truck capacity = 8 m3 per truck
Average haul distance=1 km (from borrow pit/stockpile to job site)
Number of cycles : (Cycle time 8 minutes)
Efficiency on truck capacity: 70%
Therefore, rate (2 teams) of 100,000 m3/month based on the following use a basic
production:
Production Rate = 12 x 8 x 60/8 x 0.7 x 25 x 8 = 100,800 m3/month
• For quantities up to 1,500,000 m3 use the basic production rate of
100,000 m3/month (2 work teams)
• For quantities between 1,500,000 m3 and 2,500,000 m3 adjust the equipment
to provide a production rate of 150,000 m3/month (3 work teams)
15

16. Production rates (cont’d)
• For quantities greater than 2,500,000 m3 adjust the equipment
to provide a minimum production rate of 200,000 m3/month
(4 work teams).
• The overall monthly production rate shall be adjusted to
allow 2 months buildup prior to peak production and 1
month slow down prior to completion of the work.
The quantity of embankment placed should be converted in road
length terms to enable the planner to define the interface
between subsequent activities. (e.g. when to start sub-base
activities after embankment)
16

17. Production rates (cont’d)
Planning the amount of earthworks and defining the time
required to place the whole quantity would be as follows:
1st month 50,000 m3
2nd month 100,000 m3
3rd (last month) 50,000 m3
• Duration = 1500,000 – (50,000 + 100,000 + 50,000)
100,000
= 13 months
Using higher capacity trucks and improving efficiency would
reduce this duration.
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18. Bulldozer
18

19. grader
19

20. ASPHALT PAVEMENT
Basic Equipment for Two Work Teams
No. of Items Item
2 Paver
6-12 Dump Truck (35 tons) (number
depends on hauled distance)
2 Bulldozers (200-300 hp)
1 Steel Roller
2 Rubber Rollers
1 Water Tanker Truck
1 Prime/Tack Coat Spreader
6-8 Laborers
20

21. ASPHALT PAVEMENT
Production Rates
Equipment Production Rate
Prime Coat Spreader 2 km of road, full width
Tack Coat Spreader 3 km of road, full width
Asphalt Placing Crew 2,500 tons (1,000 m3) per day – 6 no. 35 tons
trucks with hauling distance up to 10 km
Dump Truck Cycle Depends on number of trucks, truck capacity,
efficiency factor, cycle time
Production Rate Usually report on daily or weekly basis
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22. ASPHLAT TRUCK
FILLING PAVER
22

23. STEEL ROLLER
FOLLOWING PAVER
23

24. Finished Road
24

25. Finished Road
25

26. Railways
• There are many similarities
between railways and
roads, in the way of
construction and material
used, till top of
embankment level (sub-
grade for roads and sub-
ballast for railways)
• Above this level, the
activities are completely
different starting with
ballast and sleepers laying. 26

27. Bridges
• Bridges can be of different nature and types. They can
be made of steel, concrete and other materials such as
stones, timber, etc.
• They can be skew, straight, curved, flat or arched. The
presentation will be limited to straight concrete
structured bridges.
• The spans vary between long, medium and short spans.
Long 50- 350 or more meters
Medium 30-45 meters
Short 12-25 meters
27

28. Bridges
The deck structure and
method of construction
are dependent on the
span length, pier height
and accessibility.
• Long span bridges are
cable stayed.
• Medium span bridges
are box girder type.
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29. Bridge deck types
• Example of box girder
• Example of girder and slab
29

30. Method of Construction
The substructure:
• Footings on solid ground or piles
• Piers with or without a cross head
The superstructure of deck:
• Girder and slab
• Box girder
Deck and piers are often in contact via elastomeric
bearings.
Parapets are complementary to the deck. They are
installed/cast subsequent to deck casting 30

31. Cast-in-situ
box girder deck
31

32. Fragnet for typical
bridge construction
32

33. Fragnet for typical
bridge construction
33