1
Q
key rule in highway design
A
consistency
2
Q
deals with the dimensions and layout of visible features of the highway
A
geometric design
3
Q
Geometric design satisfies driver and
vehicle needs:
A
COMFORT
EFFICIENCY
SAFETY
4
Q
MAIN FEATURES OF GEOMETRIC DESIGN
A
CROSS SECTION ELEMENTS
THE GRADIENT
THE INTERSECTION
THE CONSIDERATION OF SIGHT DISTANCE
5
Q
FACTORS AFFECTING GEOMETRIC DESIGN
A
Design Speed
Topography
Traffic Factors
Design Hourly Volume and Capacity
Environmental Factors
6
Q
The most significant factor influencing
geometric design, as it directly impacts
sight distance, horizontal curve radius,
and the length of vertical curves.
A
Design Speed
7
Q
It refers to the maximum consistent
speed at which vehicles can safely
travel on a highway under favorable
weather conditions.
A
Design Speed
8
Q
It is the maximum speed that can be maintained over a specified section of the highway when weather and traffic conditions are so favorable that the design features of the highway govern.
A
Design Speed
9
Q
The _______ or terrain conditions play a major role in influencing the geometric design of highways
A
topography
10
Q
Depending on the cross slope of the land along the alignment, terrains categorized as follows:
A
Plain (0-10%)
Rolling (10-25%)
Mountainous (25-60%)
Steep (Greater than 60%)
11
Q
The geometric design of roads is influenced by various traffic-related factors, including:
A
Vehicle characteristics
Road user characteristics
12
Q
Road design must minimize negative effects on:
A
Air quality (pollution)
Noise levels
Water systems
Land use and ecosystems
13
Q
The actual distance along the road surface that a driver can clearly see from a given eye height. It represents the length of road visible ahead to the driver at any given moment.
A
Sight Distance
14
Q
Types of Sight Distance
A
Stopping Sight Distance
Overtaking Sight Distance
Intersection Sight Distance
15
Q
time between seeing an object and applying brakes
A
Driver’s Reaction Time
16
Q
THE COMPUTATION OF SIGHT DISTANCE DEPENDS ON:
A
Driver’s Reaction Time
Vehicle Speed
Brake Efficiency
Frictional Resistance
Road Gradient
17
Q
Cross slope across the pavement surface, fully formed along the circular curve.
A
Super Elevation
18
Q
This is the transverse slope on horizontal curves, provided by raising the outer edge of the pavement above the inner edge to balance the effect of centrifugal force.
A
Superelevation (banking)
19
Q
This is an arrangement in a straight line or in correct relative positions. This is the position of the layout of the central line of the highway on the ground.
A
Alignment
20
Q
This includes straight and curved paths.
A
Horizontal alignment
21
Q
This includes level and gradients.
A
Vertical alignment
22
Q
Horizontal alignment is primarily comprised of ____________ or _____________________.
A
tangent or straight sections
23
Q
In a horizontal alignment, the transition from one tangent to the next are typically ________________. These curves have a single radius value.
A
simple curves
24
Q
A ______________ is used in some
instances of horizontal alignment.
A
spiral transition
25
IMPORTANT INFORMATION IN HORIZONTAL ALIGNMENT
RADIUS
THE LENGTH OF THE CURVE
THE CHANGE IN DIRECTION OF THE TWO TANGENTS
OTHER FACTORS DEPENDING ON YOUR NEEDS
26
Vertical alignment is primarily comprised of _____________, which represents grades which can either be flat, uphill or downhill.
tangents
27
The typical vertical curve is a ___________________.
symmetric, parabolic curve
28
IMPORTANT INFORMATION IN VERTICAL ALIGNMENT
THE ELEVATION IN THE BEGINNING OF THE CURVE
THE GRADES OF THE TWO TANGENTS
THE LENGTH OF THE CURVE
29
THE LOCATION WHERE THE TANGENT INTERSECT
POINT OF INTERSECTION
30
THE LOCATION WHERE THE VEHICLES LEAVES THE TANGENT SECTION AND BEGINS TO DRIVE ALONG THE CURVE
THE POINT OF CURVATURE
31
THE LOCATION WHERE CURVE ENDS AND THE VEHICLE RETURNS BACK TO THE TANGENT
POINT OF TANGENCY
32
A ____________ is nothing but an arc which connects two straight lines which are separated by same angle called deflection angle.
curve
33
These are necessary in both geometric and pavement design so that the horizontal and vertical curves make the infrastructure road user friendly and decrease the risk of hazardous instance.
Road curves
34
Types of Curves
Horizontal Curve
- Simple Curve
- Compound Curve
- Reverse Curve
Vertical Curve
- Summit Curve
- Valley Curve
35
The road curves which are provided at turning points so to get gradual change in the direction of alignment of a road or a track are termed as _________________. Generally, these types of curves are provided in the horizontal plane.
horizontal curves
36
Horizontal curve can be a/an ___________, ____________, ____________, ___________, or ___________.
arc of a circle, spiral, ellipse, and a parabola or a hyperbola
37
The curve which consists of a single arc of a circle of which two straight tangents further connect and brings about a deflection of the road through an angle. It is normally presented by the length of its radius of by the degree of a curve. This type of curve is provided at every change in alignment of the road or railway track in a plain and in hilly areas.
Simple Road Curve
38
A curve of having the series of two and more simple curves of different radii curving in the same direction.
Compound Road Curves
39
This curve consists of two simple curves having equal or different radii turning in opposite direction. The two centers of curves are on opposite sides of a common tangent BD.
Reverse Road Curve
40
This is defined as the curve in which radius varies gradually from infinity to a finite value equal to that of the circular curve to be connected and vice versa. These curves are commonly used in railway tracks between the circular curve and a tangent so as to provide easy and gradual change in direction.
transition curve
41
The curves which are provided in the alignment of road or track at change of
gradient.
Vertical Curve
42
The curves which are having convex surface on upward side.
Summit Curve
43
The road curves which are having the convex surface on downward side.
Valley Curve
44
It connects falling gradient with rising gradient. Convexity of a curve is generally downwards. Also called as sag curve.
Valley Curve
45
This represents how steep a slope is: Uphill is positive, and Downhill slopes are negative.
Gradient
46
The gradient symbol “m” is for how “mountainous” a slope is. _______________ invented Gradient and assigned the letter “m” as “montagne”, which is a French of Mountain.
Rene Descartes
47
Is the rate of rise or fall along the length of the road with respect to the horizontal.
Gradient
48
This is the most important part of the construction of roads.
gradient
49
FACTORS AFFECTING GRADIENT:
Nature of the ground.
Drainage required.
Nature of the traffic.
The type of road surface.
The total height to be covered.
Road and railway interaction.
Safety Required.
Bridge Approaches.
50
This is the gradient, which is usually adopted while making the alignment of the road. This is used for designing the road because it gives maximum safety at minimum cost.
ruling gradient
51
This gradient is adopted when the ruling gradient results in enormous increase in cost of construction. On rolling terrain and
hilly terrain it may be frequently necessary to adopt this.
limiting gradient
52
These are very steeper gradients given at unavoidable situations. In mountainous and steep terrain, successive exceptional gradients must be separated by a minimum 100-meter length gentler gradient.
Exceptional gradient
53
This is important only at locations where surface drainage is important.
Minimum gradient
54
A minimum of __________ may be sufficient for concrete drain and _________ for open soil drains are found to give satisfactory performance.
1 in 500
1 in 200
55
It is the ratio of total rise or fall to the horizontal distance between any two points along the alignment of the road.
Average gradient
56
The gradient on which a motor vehicle moving with a constant speed continues to descend with the same speed without any application of power brakes.
Floating gradient
57
a vertical section of the ground and roadway at right angles to the centerline of the roadway, including all elements of a highway or street from right-of-way line
roadway cross-section
58
Cross Section Elements
Carriage Way
Road Margins
Formation Width
Right of Way
Berm
Side Slope
Boundary Stone
Building Line
Kerbs
Camber
59
Consists of a width of road on which a
vehicle is not restricted by any physical
barriers or separation to move laterally.
Carriage Way
60
generally consists of a number of traffic lanes together with any associated shoulder, but may be a sole lane in width (for example, a highway off ramp)
Carriage Way
61
The width of pavement way on which
vehicles travel.
Carriage Way
62
The portion of the road beyond the carriageway and on the roadway.
Road Margins
63
Various elements that form the road margins are:
Shoulder
Parking lanes
Bus-bays
Truck lay-by
Service roads
Cycle track
Footpath
Guard rails
64
These are provided along the road edge to serve as an emergency lane for vehicles for the vehicles requiring accidental repairs. They provided external stability to the carriageway
Road Shoulders
65
They provide space for animal drawn vehicles, cyclists and pedestrians when a fast-moving vehicle crosses them. They provide space for erecting road signals.
Road Shoulders
66
These are provided in urban lanes for side parking.
Parking lanes
67
This is preferred because it is safe for the vehicles moving on the road.
Parallel parking
68
The parking lane should have a minimum of ______ width in the case of parallel parking.
3.0 m
69
These are provided by recessing the kerbs for bus stops. They are provided so that they do not obstruct the movement of
vehicles in the carriage way.
Bus bays
70
Bus bays should be at least __________ away from the intersection so that the traffic near the intersections is not affected.
75 meters
71
A paved area at the side of a highway designated for drivers to stop in, for emergency parking, or where vehicles can wait, with larger lay-bys possibly having facilities.
Truck Lay-by
72
These give access to access-controlled highways like freeways and expressways. They run parallel to the highway and will be usually isolated by a separator and access to the highway will be provided only at selected points.
Service roads or frontage roads
73
These roads are provided to avoid
congestion in the expressways and
also, the speed of the traffic in those
lanes are not reduced.
Service roads
74
These are provided in urban areas when the volume of cycle traffic is high minimum width of 2 meter is required, which may be increased by 1 meter for every additional track.
Cycle Track
75
These are exclusive right of way to
pedestrians, especially in urban areas.
They are provided for the safety of the
pedestrians when both the pedestrian
traffic and vehicular traffic is high
Footpaths
76
Minimum width of a footpath
1.5 meter
77
They are provided at the edge of the shoulder usually when the road is on an embankment. They serve to prevent the vehicles from running of the embankment, especially when the height of the fill exceeds 3 m.
Guard Rails
78
They also give better visibility of curves at night under headlights of vehicles.
Guard Rails
79
It is the top width of the highway embankment or the bottom width of cutting excluding the side drain.
Formation Width
80
It is the area of land acquired or the land along its alignment. It is the distance between boundary stones of road on either side of road.
Right of Way
81
Distance between the road toe and the inner edge of borrow pit. It prevents the erosion of embankment soil.
Berm
82
These should be made as gentle as possible to enhance safety for traffic and improve aesthetic appeal.
Side slopes
83
To indicate the boundary of land acquired for road, stones are driven into the ground at about 30 m distance on either side from the center line of the road. These stones are known as _________________.
boundary stones
84
The distance from the center line of road on either side within construction of buildings which is not permitted.
Building Line
85
The boundaries between pavement and shoulders of footpaths.
Kerbs
86
These types of kerbs are provided such
that they encourage the traffic to remain
in the through traffic lanes and also allow
the driver to enter the shoulder area with
little difficulty. The height of this kerb is
about 10 cm above the pavement edge
with a slope which allows the vehicle to
climb easily. This is usually provided at
medians and channelization schemes and
also helps in longitudinal drainage.
Low or mountable kerbs
87
DIFFERENT TYPES OF KERBS
Low or mountable kerbs
Semi-barrier type kerbs
Barrier type kerbs
Submerged kerbs
88
When the pedestrian traffic is high, these kerbs are provided. Their height is 15 cm above the pavement edge. This type of kerb prevents encroachment of parking vehicles, but at acute emergency it is possible to drive over this kerb with some difficulty.
Semi-barrier type kerbs
89
They are designed to discourage vehicles
from leaving the pavement. They are provided when there is considerable amount of pedestrian traffic. They are placed at a height of 20 cm above the pavement edge with a steep batter.
Barrier type kerbs
90
They are used in rural roads. The kerbs are provided at pavement edges between the pavement edge and shoulders. They provide lateral confinement and stability to the pavement.
Submerged kerbs
91
This is the slope provided to the road surface in traverse direction to drain off water from the surface.
Camber or cross slope
92
These involve the processes of excavation, transportation, placement, and compaction of soil or rock to form the roadbed or railway formation. It is one of the most important and cost-intensive parts of construction.
Earthworks
93
FACTORS AFFECTING EARTHWORKS DESIGN
TOPOGRAPHY
SOIL CHARACTERISTICS
GROUNDWATER TABLE
ECONOMY
ENVIRONMENTAL CONSIDERATIONS
94
AFFECTS STABILITY AND NEED FOR SUB DRAINAGE.
Groundwater Table
95
PREFERENCE FOR BALANCE OF CUT AND FILL TO REDUCE HAULAGE.
Economy
96
Types of Earthworks
Clearing and Grubbing
Removal of Structures and Obstructions
Excavation
Compaction
Foundation
Embankment
97
This is the removal and disposal of all surface objects including vegetation, grass, stumps, trees and other protruding obstructions not designated to remain along the roadway prior to commencing of any earth moving activity.
Clearing and Grubbing
98
It consists of the taking away, wholly or in part, and the satisfactory disposal off the site of all structures within the construction site and right-of-way which have not been designated to remain.
Removal of Structures and Obstructions
99
It consists of all the excavation for grading and draining the roadway, and includes loading, hauling, and placing the excavated
materials from roadway cuts to construct embankments or its disposal to a designated location.
Excavation
100
Types of Excavation
Unsuitable Excavation
Common Excavation
Rock Excavation
Surplus Excavation
Structure Excavation
101
This is the removal and disposal of saturated mixture of soils and organic matter such as peat and muck which are not suitable as road foundation materials which can cause instability in embankments.
Unsuitable Excavation
102
This refers to the excavation of common materials along the road traverse that may be placed as fill or disposed as surplus.
Common Excavation
103
This is the digging on the ground necessary along the roadway traverse to remove encountered rock to its designed elevation either for use as an embankment or for hauling to a waste deposit area.
Rock Excavation
104
These are suitable materials excavated
along the road traverse which are
disposed as excess in the formation
of embankment sub-grade.
Surplus Excavation
105
Types of Surplus Excavation
1. Surplus from Common Excavation
2. Surplus from Rock Excavation
3. Surplus from Excavation
106
These consists of the necessary excavation, removal and satisfactory disposal of all materials within the stipulated limits.
Structure Excavation
107
Types of Structure Excavation
1. Culvert Excavation
2. Dry Excavation
3. Wet Excavation
4. Rock Excavation
5. Bridge Excavation (Unclassified)
108
This is a process of increasing soil density and removing air, usually by mechanical means. The size of the individual soil particles does not change, neither is water removed.
Compaction
109
This is a structural element that links a structure to the ground and transfers loads from the structure to the ground.
Foundation
110
Foundations are classified as either __________ or _________.
shallow or deep
111
These are included in portions where the
grade line of the roadway be raised to some distance above the level of the existing ground surface to maintain design standards or prevent damage to the highway through action of surface or ground water.
Embankment
112
removing of soil or excavating of soil
Cut
113
backfilling or embanking or placing embankment
Fill
114
TYPES OF EARTH VOLUMES
BANK VOLUME
LOOSE VOLUME
COMPACTED VOLUME
115
VOLUME OF MATERIAL AS IT LIES IN THE NATURAL STATE.
Bank Volume
116
VOLUME OF MATERIAL AFTER IT HAS BEEN DISTURBED BY A LOADING AND EXCAVATING PROCESS.
Loose Volume
117
VOLUME OF MATERIAL IN THE COMPACTED STATE, ALSO REFERRED TO AS A NET IN-PLACE VOLUME.
Compacted Volume
118
TYPES OF CUT AND FILL SECTIONS
Level Section
Three-level Section
Five-level Section
Irregular Section
119
The ground is level in a direction transverse to the centerline.
Level Section
120
Rod readings are taken at each slope stake in addition to the reading taken at the center, as is normally done where the ground is sloping.
Three-level Section
121
Rod readings are taken at the center stake, slope stakes and at points on each side of the center at a distance half the width or roadbed.
Five-level Section
122
Observations are taken to points at irregular intervals.
Irregular Section
HRE
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