Unit – 2
Surveying and Transportation Engineering
Introduction to digital mapping
Digital mapping (also called digital cartography) is the process by which a collection of data is compiled and formatted into a virtual image. The primary function of this technology is to produce maps that give accurate representations of a particular area, detailing major road arteries and other points of interest. The technology also allows the calculation of distances from one place to another.
Although digital mapping can be found in a variety of computer applications the main use of these maps is with the Global Positioning System, or GPS satellite network, used in standard automotive navigation systems.
Principles of survey
The two principles are
1) LOCATION OF A POINT BY MEASUREMENT FROM TWO POINTS OF REFERENCE:
The relative positions of the points to be surveyed should be located by taking measurement from at least two points of reference. Points of reference are points whose position is already fixed
2) SECOND PRINCIPLE IS TO WORK FROM WHOLE TO PART:
It is very essential to establish first a system of control points and to fix them with higher precision. Minor control points can be established by less precise methods and the details can be located using these minor control points by running minor traverses.
Introduction to various survey instruments
Electronic Distance Measurement
Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves. EDM is commonly carried out with digital instruments called theodolites. EDM instruments are highly reliable and convenient pieces of surveying equipment and can be used to measure distances of up to 100 kilometers. Each piece of EDM equipment available at Engineer Supply provides dependably accurate distance measurements displayed on an easy-to-read digital screen. Devices known as total stations share similarities with theodolites and can be used to measure distances as well as angles.
Lasers
Laser surveying instruments are primarily used to set elevation, grade or to plumb construction elements. Midwest Construction Equipment has created a list of commonly used laser surveying instruments, along with a brief description of their uses.
Laser Levels – Laser levels point or rotate to create a reference point, line, or plane. When used outside, laser levels are almost always used with a receiver attached to a grade rod or mounted on heavy equipment for laser machine control. When used inside, a visible beam guides construction activity, but sometimes a receiver is used for large work areas. Some units have the ability to slope the plane on one or two axes to set a grade or slope. Laser levels used for machine control are more powerful.
Laser Receivers – Receivers can attach to grade rods. Larger laser receivers are mounted on heavy equipment for machine control. Laser receivers are specific to the wavelength of light received. Newer laser receivers are universal for the wavelength of laser light received.
Pipe Lasers – Used to set precise grade of pipes, drains or sewers, and are typically used with a pipe type- and size-specific target set.
3D Scanners – These devices use multi-point scanning to produce an accurate 3D model of any indoor or outdoor man-made or natural structure, mostly for project design support.
Distance Meters – Whether a handheld device, part of a total station, or another type of surveying instrument, distance meters bounce laser energy off a surface or a target to measure distances with great accuracy.
Total Stations
A total station is an optical instrument used in modern surveying. It is a combination of an electronic theodolite (transit), an electronic distance measuring device (EDM) and software running on an external computer, such as a laptop or data collector.
Digital planimeter
An instrument used to measure the areas of maps or planes and flat surfaces in general. It is called a mechanical integrator and has a tracing point that performs double measurement of the perimeter of the relevant surfaces. The reading is numeric, appearing in digital format on a small monitor.
Modern survey methods
MODERN SURVEYING EQUIPMENT
- Digital Level
- EDMI – ELECTRO MAGNETIC
- Total Station
- Remote Sensing
Introduction to GIS, GPS and their applications
Geographic Information Systems
GIS applications enable the storage, management, and analysis of large quantities of spatially distributed data. These data are associated with their respective geographic features. For example, water quality data would be associated with a sampling site, represented by a point. Data on crop yields might be associated with fields or experimental plots, represented on a map by polygons.
A GIS can manage different data types occupying the same geographic space. For example, a biological control agent and its prey may be distributed in different abundances across a variety of plant types in an experimental plot. Although predator, prey, and plants occupy the same geographic region, they can be mapped as distinct and separate features.
The ability to depict different, spatially coincident features is not unique to a GIS, as various computer aided drafting (CAD) applications can achieve the same result. The power of a GIS lies in its ability to analyze relationships between features and their associated data. This analytical ability results in the generation of new information, as patterns and spatial relationships are revealed.
The Global Positioning System
GPS technology has provided an indispensable tool for management of agricultural and natural resources. GPS is a satellite- and ground-based radio navigation and locational system that enables the user to determine very accurate locations on the surface of the Earth. Although GPS is a complex and sophisticated technology, user interfaces have evolved to become very accessible to the non-technical user. Simple and inexpensive GPS units are available with accuracies of 10 to 20 meters, and more sophisticated precision agriculture systems can obtain centimeter level accuracies.
Applications
The uses of GIS, GPS, and RS technologies, either individually or in combination, span a broad range of applications and degrees of complexity. Simple applications might involve determining the location of sampling sites, plotting maps for use in the field, or examining the distribution of soil types in relation to yields and productivity. More complex applications take advantage of the analytical capabilities of GIS and RS software. These might include vegetation classification for predicting crop yield or environmental impacts, modeling of surface water drainage patterns, or tracking animal migration patterns.
Role of transportation in national development
The primary function of transportation is the transfer of messages and information. It is also needed for rapid movement of troops in case of emergency and finally movement of persons and goods. The political decision of construction and maintenance of roads has resulted in the development of transportation system.
- Economic development
Investment in transport is a key to economic growth. Transport sector contributes to 6% of Indian GDP
- Industrial development
Turning of local market into national market. Increases the export import from the. Availability of raw material. Connecting the rural market or distributor to the cities. Increase the Productivity of different industries.
- Social and cultural development
Encourage the globalization. Improved the living condition of people. Influence the formation urban societies. exchange and adoption of different culture
Various modes of Transportation
These most common five modes of transport are
- Railways
- Roadways
- Airways
- Waterways
- Pipelines
The Roads classified in to THREE classes
1. Primary System
a) Expressways
b) National Highways (NH)
2. Secondary System
a) State Highways (SH).
b) Major District Roads (MDR)
3. Tertiary system or Rural Roads
a) Other District Roads (ODR).
b) Village Roads
(1)EXPRESSWAYS
An expressway is a divided highway for high-speed traffic with at least, partial control of access. Have superior facilities and design standards. These may be NH of SH. Example ORR in Hyderabad ( 158 km ) Mumbai- Pune Expressway (93 km) Total Length in India = 3180 km
(ii) National Highways (NH)
Main Highways running through the length and breadth of country. Connects major ports, foreign highways, State capitals, large industrial and tourist centers. Total length of NH = 70548 K
(iii) State Highways (SH)
Arterial routs of a State linking District Head Quarters and important cities within the state. Connects National Highways or highways of neighbouring states. Total length of SH = 1,31,899 km
(iv) Major District Roads (MDR)
Important roads within a district serving areas of production and markets. Connects some other MDR or with National Highways. Total Length of MDR = 4,67,763
(v) Other District Roads
(ODR Serves rural areas of production. Connects to market centres, taluka headquarters, block development headquarters or other main roads.
(vi) Village Roads (VR)
Roads connecting villages or groups of villages with each other and to the nearest road of higher category Total length of ODR and VR (Rural Roads) = 26,50,000
Types of Pavements
There are two types of pavements based on design considerations i.e. flexible pavement and rigid pavement. Difference between flexible and rigid pavements is based on the manner in which the loads are distributed to the sub grade. Before we differentiate between flexible pavements and rigid pavements, it is better to first know about them. Details of these two are presented below:
Flexible Pavements
Flexible pavement can be defined as the one consisting of a mixture of asphaltic or bituminous material and aggregates placed on a bed of compacted granular material of appropriate quality inlayers over the sub grade. Water bound macadam roads and stabilized soil roads with or without asphaltic toppings are examples of flexible pavements. The design of flexible pavement is based on the principle that for a load of any magnitude, the intensity of a load diminishes as the load is transmitted downwards from the surface by virtue of spreading over an increasingly larger area, by carrying it deep enough into the ground through successive layers of granular material. Thus for flexible pavement, there can be grading in the quality of materials used, the materials with high degree of strength is used at or near the surface. Thus the strength of sub grade primarily influences the thickness of the flexible pavement.
Rigid Pavements
A rigid pavement is constructed from cement concrete or reinforced concrete slabs. Grouted concrete roads are in the category of semi-rigid pavements. The design of rigid pavement is based on providing a structural cement concrete slab of sufficient strength to resists the loads from traffic. The rigid pavement has rigidity and high modulus of elasticity to distribute the load over a relatively wide area of soil.
Traffic Signs
- Regulatory signs
Mandatory signs
Give notice of traffic laws or regulations
- Warning signs
Cautionary signs
Give notice of a situation that might not be readily apparent
- Informative signs
Guide signs
Show route designations, distances, services, points of interest, etc.
Parking system
As the name itself suggests means the area allotted for Parking purpose at the sides of the roads. For efficiency in Parking system; the On street Parking is divided into two types:
- Angular Parking
- Parallel Parking
- Perpendicular Parking (efficient Parking Method)
Parallel Parking System
The vehicles are parked one behind the other. The Parking lot is designed as per the area required if Parallel Parking is adopted. It has been surveyed that the area required for Parallel Parking is much lesser that required for Angular Parking. Therefore, a greater number of vehicles can be parked in this Parking System. For this reason, this Parking system is generally adopted.
Angular Parking
The vehicles are parked at an angle. It may be a 30 degree angle or 45 degree. The vehicles can be easily reversed if parked at an angle. Hence, proving as an efficient Parking System in case of vehicular circulation. The major drawback of “Angular Parking System” is that it requires larger space for parking than required for Parallel Parking. Hence this system is adopted where the space is available in plenty.
Perpendicular Parking
The vehicles are parked at right angle to the road. It is an efficient system of Parking.
Causes of Accidents
Accidents are rare, multifactor and random. It is not a chance but a chain of events involving:-
- Road Users
- Excessive speed and rash driving, violation of traffic rules, failure to perceive traffic situation or sign or signal in adequate time,
- Carelessness, fatigue, alcohol, sleep etc.
- Vehicle
- Defects such as failure of brakes, steering system, tire burst, lighting system, etc
Reference Books
- A Text Book of Building Materials, by C.J. Kulkarrni
- Building Materials, by P. C. Varghese
- Building Construction, by P. C. Varghese
