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Note for Transportation Engineering 1 - TE1 by G Venkatesh yadav

  • Transportation Engineering 1 - TE1
  • Note
  • Jawaharlal Nehru Technological University Anantapur (JNTU) College of Engineering (CEP), Pulivendula, Pulivendula, Andhra Pradesh, India - JNTUACEP
  • Civil Engineering
  • B.Tech
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www.alljntuworld.in JNTU World CHAPTER 4 INTERSECTION DESIGN or ld Types of Intersections Conflicts at Intersections Requirements of At –Grade intersectionTypes of at-Grade IntersectionsChanalization -Traffic Islands Types of Grade Separated Intersections Rotary Intersection –concept of Rotary Design factors of rotary Advantages and limitations of rotary intersections. CHAPTER 5 HIGHWAY MATERIAL, CONSTRUCTION ANDMAINTENANCE: JN TU W Highway material characterization Subgrade soil Stone aggregate Bitumen materials Construction of gravel road Construction of water bound macadam road Construction of bituminous pavements Surface dressing Bitumen bound macadam Bituminous concrete Construction of cement concrete pavements Construction of joints in cement concrete pavements Joint filter and seal Pavement failures Maintenance of highways Highway Drainage. II Downloaded From JNTU World (http://www.alljntuworld.in)

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www.alljntuworld.in JNTU World CHAPTER 1 HIGHWAY DEVELOPMENT AND PLANNING Overview History of highway engineering or ld Road transport is one of the most common mode of transport. Roads in the form of trackways, human pathways etc. were used even from the pre-historic times. Since then many experiments were going on to make the riding safe and comfort. Thus road construction became an inseparable part of many civilizations and empires. In this chapter we will see the di erent generations of road and their characteristic features. Also we will discuss about the highway planning in India. The history of highway enginnering gives us an idea about the roads of ancient times. Roads in Rome were constructed in a large scale and it radiated in many directions helping them in military operations. Thus they are considered to be pioneers in road construction. In this section we will see in detail about Ancient roads, Roman roads, British roads, French roads etc. Ancient Roads TU W The rst mode of transport was by foot. These human pathways would have been developed for speci c 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 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 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. To provide adequate strength to carry the wheels, the new ways tended to follow the sunny 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. 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. Roman roads JN 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 2.7 m Sloping Wearing Surface 5cm thick Shoulder Slope 1:20 ______________ ______________ _ _______ Side drain ______________ _ _ _ __ ____________________________________ 4 Downloaded From JNTU World (http://www.alljntuworld.in)

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www.alljntuworld.in JNTU World Broken stones 8cm thick Large foundation stones on edge17cm thick Figure 2:2: French roads 2.2.3 or ld 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 are still existing. Roman roads were always constructed on a rm - 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 tra c, a surface course of large 250 mm thick hexagonal ag stones were provided. A typical cross section of roman road is given in Figure 2:1 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 mortar and they added gravel to this mortar to make concrete. Thus concrete was a major Roman road making innovation. French roads TU W The next major development in the road construction occurred during the regime of Napoleon. The signi cant contributions were given by Tresaguet in 1764 and a typical cross section of this road is given in Figure 2:2. He developed a cheaper method of construction than the lavish and locally unsuccessful revival of Roman practice. The pavement used 200 mm pieces of quarried stone of a more compact form and shaped such that they had at least one at side which was placed on a compact formation. Smaller pieces of broken stones were then compacted into the spaces between larger stones to provide a level surface. Finally the running layer was made with a layer of 25 mm sized broken stone. All this structure was placed in a trench in order to keep the running surface level with the surrounding country side. This created major drainage problems which were counteracted by making the surface as impervious as possible, cambering the surface and providing deep side ditches. He gave 4.5 m Cross slope ___________ _____________ _________________ _____________ __ _ __ _ __ _________________ ___________ _ _ _________ _ JN _ Side drain _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________ _________________CompactedSubgradeslope1:36 50mm Broken Stones, 100mm thick 37.5mm Broken Stones, 100mm thick Surface Course 20mm, 50mm thick Figure 2:3: British roads much importance for drainage. He also enunciated the necessity for continuous organized maintenance, instead of intermittent repairs if the roads were to be kept usable all times. For this he divided the roads between villages into sections of such length that an entire road could be covered by maintenance men living nearby. 2.2.4 British roads 5 Downloaded From JNTU World (http://www.alljntuworld.in)

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www.alljntuworld.in JNTU World The British government also gave importance to road construction. The British engineer John Macadam introduced what can be considered as the rst scienti c 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 sti ness and a better running surface than an expensive pavement founded on large stone blocks. Thus he introduced an economical method of road construction. 2.2.5 or ld The mechanical interlock between the individual stone pieces provided strength and sti ness to the course. But the inter particle friction abraded the sharp interlocking faces and partly destroy the e ectiveness of the course. This e ect was overcome by introducing good quality interstitial ner material to produce a wellgraded mix. Such mixes also proved less permeable and easier to compact. A typical cross section of British roads is given in Figure 2:3. 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-e ective construction technologies are used. Development of new equipments help 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. W 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 of other modes of transportation like railways and travel by air. While the above development 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, exibility, convenience and comfort. This led to the increase in vehicular trafficespecially in private transport network. Thus road space available was becoming insu cient to meet the growing demand of trafficand congestion started. In addition, chances for accidents also increased. This has led to the increased attention towards control of vehicles so TU that the transport infrastructure was optimally used. Various control measures like trafficsignals, providing roundabouts and medians, limiting the speed of vehicle at speci c zones etc. were implemented. With the advancement of better roads and e cient control, more and more 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. 2.3 Highway planning in India JN Excavations in the sites of Indus valley, Mohenjo-dero and Harappan civilizations revealed the existence of planned roads in India as old as 2500-3500 BC. The Mauryan kings also built very good roads. Ancient books like Arthashastra written by Kautilya, a great administrator of the Mauryan times, contained rules for regulating tra c, depths of roads for various purposes, and punishments for obstructing tra c. During the time of Mughal period, roads in India were greatly improved. Roads linking North-West and the Eastern areas through gangetic plains were built during this time. After the fall of the Mughals and at the beginning of British rule, many existing roads were improved. The construction of Grand-Trunk road connecting North and South is a major contribution of the British. However, the focus was later shifted to railways, except for feeder roads to important stations. 2.3.1 Modern developments The rst World war period and that immediately following it found a rapid growth in motor transport. So need 6 Downloaded From JNTU World (http://www.alljntuworld.in)

Lecture Notes