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Highway and Traffic Engineering

by Engineering KingsEngineering Kings
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Engineering Kings
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Downloaded CE6504 HIGHWAY ENGINEERING V – SEMESTER ww w.E UNIT 1 HIGHWAY PLANNING AND ALIGNMENT asy Prepared by MR. L. RANJITH KUMAR M.E., (Ph.D) En ASSISTANT PROFESSOR/CIVIL gin eer ing .ne DEPARTMENT OF CIVIL ENGINEERING PANIMALAR ENGINEERING COLLEGE, CHENNAI - 123 1 Downloaded t
Downloaded HISTORY OF ROAD DEVELOPMENT IN INDIA: In India roads were developed during the following era.  Ancient period (3500 BC)  Mughal period (15th Century)  British period (17 th and 18th Century)  Free India (1950 onwards) Ancient Roads: The first mode of transport was by foot. These human pathways would have been ww developed for specific purposes leading to camp sites, food, streams for drinking water etc. The next major mode of transport was the use of animals for transporting both men and w.E materials. Since these loaded animals required more horizontal and vertical clearances than the walking man, track ways emerged. The invention of wheel in Mesopotamian civilization asy led to the development of animal drawn vehicles. Then it became necessary that the road surface should be capable of carrying greater loads. Thus roads with harder surfaces emerged. En To provide adequate strength to carry the wheels, the new ways tended to follow the sunny gin drier side of a path. These have led to the development of foot-paths. After the invention of wheel, animal drawn vehicles were developed and the need for hard surface road emerged. eer Traces of such hard roads were obtained from various ancient civilization dated as old as 3500 BC. The earliest authentic record of road was found from Assyrian empire constructed about 1900 BC. ing .ne The earliest large scale road construction is attributed to Romans who constructed an extensive system of roads radiating in many directions from Rome. They were a remarkable achievement and provided travel times across Europe, Asia minor, and north Africa. Romans recognized that the fundamentals of good road construction were to provide good drainage, good material and good workmanship. Their roads were very durable, and some still exist. 2 Downloaded t
Downloaded Roman roads were always constructed on a firm - formed subgrade strengthened where necessary with wooden piles. The roads were bordered on both sides by longitudinal drains. The next step was the construction of the agger. This was a raised formation up to a 1 meter high and 15 m wide and was constructed with materials excavated during the side drain construction. This was then topped with a sand leveling course. The agger contributed greatly to moisture control in the pavement. The pavement structure on the top of the agger varied greatly. In the case of heavy traffic, a surface course of large 250 mm thick hexagonal flag stones were provided. A typical cross section of roman road is given in Figure. The main features of the Roman roads are that they were built straight regardless of gradient and used heavy foundation stones at the bottom. They mixed lime and volcanic puzzolana to make ww mortar and they added gravel to this mortar to make concrete. Thus concrete was a major w.E Roman road making innovation. British Road: asy En gin eer ing .ne The British government also gave importance to road construction. The British engineer John Macadam introduced what can be considered as the first scientific road construction method. Stone size was an important element of Macadam recipe. By empirical observation of many roads, he came to realize that 250 mm layers of well compacted broken angular stone would provide the same strength and stiffness and a better running surface than an expensive pavement founded on large stone blocks. Thus he introduced an economical method of road construction. The mechanical interlock between the individual stone pieces provided strength and stiffness to the course. But the inter particle friction abraded the sharp interlocking faces and partly destroy the effectiveness of the course. This effect was overcome by introducing good quality interstitial finer material to produce a well-graded mix. Such mixes also proved less permeable and easier to compact. A typical cross section of British roads is given in Figure 3 Downloaded t
Downloaded Modern Roads: The modern roads by and large follow Macadam's construction method. Use of bituminous concrete and cement concrete are the most important developments. Various advanced and cost-effective construction technologies are used. Development of new equipments helps in the faster construction of roads. Many easily and locally available materials are tested in the laboratories and then implemented on roads for making economical and durable pavements. Scope of transportation system has developed very largely. Population of the country is increasing day by day. The life style of people began to change. The need for travel to various places at faster speeds also increased. This increasing demand led to the emergence ww of other modes of transportation like railways and travel by air. While the above development w.E in public transport sector was taking place,the development in private transport was at a much faster rate mainly because of its advantages like accessibility, privacy, flexibility, convenience and comfort. asy This led to the increase in vehicular traffic especially in private transport network. Thus road space available was becoming insufficient to meet the growing En demand of traffic and congestion started. In addition, chances for accidents also increased. This has led to the increased attention towards control of vehicles so that the transport gin infrastructure was optimally used. Various control measures like traffic signals, providing eer roundabouts and medians, limiting the speed of vehicle at specific zones etc. were implemented. ing With the advancement of better roads and efficient control, more and more .ne investments were made in the road sector especially after the World wars. These were large projects requiring large investment. For optimal utilization of funds, one should know the travel pattern and travel behavior. This has led to the emergence of transportation planning and demand management. Modern Developments: The First World War period and that immediately following it found a rapid growth in motor transport. So need for better roads became a necessity. For that, the Government of India appointed a committee called Road development Committee with Mr.M.R. Jayakar as the chairman. This committee came to be known as Jayakar committee. 4 Downloaded t

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