Highway Engineering Introduction PDF

# Highway Engineering Introduction Prepared by M.sc: Hiwa Hamid 2023-2024 ## Highway Engineering - Is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effectiv...

# Highway Engineering Introduction Prepared by M.sc: Hiwa Hamid 2023-2024 ## Highway Engineering - Is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and goods. - Highway engineering became prominent towards the latter half of the 20th Century after World War II. Standards of highway engineering are continuously being improved. - Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, geometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance. ## Introduction - Road transport is one of the most common modes of transport. - Roads in the form of trackways, human pathways etc. were used even from the pre-historic times. - Thus road construction became an inseparable part of many civilizations and empires. - The history of highway engineering 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. ## Ancient Roads - The first mode of transport was by foot. - These human pathways would have been 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 materials. - The invention of the wheel in Mesopotamian civilization led to the development of animal drawn vehicles. - After the invention of the wheel, animal drawn vehicles were developed and the need for hard surface road emerged. - First hard surface was discovered in Mesopotamia about 3500 Bc. - Many of Roman Roads are still in existence even after 2000 years. - The earliest authentic record of road was found from Assyrian empire constructed about 1900 BC. - Mr. Pierre Tresaquet developed an improved method of construction in 1764 in France. - At it period Mr.John Metcalf constructed about 290 Km Road in Northern England. - Telford and Macadam were the pioneers in Road development in England. Telford believed in using heavy foundation stones over the soil sub-grade while Mac-Adam advocated the use of compacted crushed aggregate layer at the bottom. Mac-Adams Method stills in use. ## Roman Roads - 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. - 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. - The total thickness of road section worked out as high as 750 mm to 1200 mm. ## Roman Road Construction A diagram depicting a cross-section of a Roman road is provided. The diagram labels the following elements: - Kerbstone - Lime concrete - Broken Stones in Lime cocrete - Large stone slabs 10-15 cm thick - 10-20 cm Thick Subgrade - Large Foundation Stones in Lime Mortar - Typical road width 5.5-6 metres (18-20 feet) - Drain - Kerb stone - Drain - Compacted slabs of crushed stone in cement - Dressed stone in cement - Stone blocks - Stone ditch ## French Roads or Tresaguet Road - The next major development in the road construction occurred during the regime of Napoleon. - The significant contributions were given by Tresaguet in 1764 and a typical cross section of this road is given in Figure below. - 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 flat 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. ## Telford Construction - The next development was done by Scottish engineer Thoms Telford (1757-1834). - The foundation was prepared for a road with width of 9 m and it was levelled. - Large size stones of width equal to 40 mm and depth 170 to 220 mm were then laid. - After filling the spaces between foundation stones, two layers of stones having compacted thickness of 100 and 50 mm respectively laid in the center of 4.5 m. of width. - The top layer of road was made of 40 mm thick binding layer of gravel. ## British Road - 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. ## Highway Development in Iraq - As mentioned above first road constriction in Iraq 3500BC. - During Equitation 1917 English troops constructed military roads between Iraqi main Cities. - After Nationalization Iraqi petrol 1972 many roads were been opened. ## 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 equipment 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. - 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. ## Highway Location - Selecting the location of a proposed highway is an important initial step in its design BASED ON: - Topography - Soil characteristics - Environmental factors such as noise and air pollution - Economic factors. - The data required for the decision process are usually obtained from different types of surveys, depending on the factors being considered. These techniques include: - Ground Surveys, (transit, level ........) - Remote sensing, which uses aerial photographs for the preparation of maps or Global Positioning Systems (GPS) using orbiting satellites. - Computer graphics, which is a combination of the analysis of computer-generated data with a display on a computer monitor. ## Principles of Highway Locations - The basic principle for locating highways is that roadway elements such as curvature and grade must blend with each other to produce a system that provides for the easy flow of traffic at the design capacity, while meeting design criteria and safety standards. - The highway should also cause a minimal disruption to historic and archeological sites and to other land-use activities. - The highway location process involves four phases: - Office study of existing information - Reconnaissance survey - Preliminary location survey - Final location survey ## 1-Office Study of Existing Information - The first phase in any highway location study is the examination of all available data of the area in which the road is to be constructed. - Data should be obtained on the following characteristics of the area: - Engineering, including topography, geology, climate, and traffic volumes. - Social and demographic, including land use and zoning patterns. - Environmental, including types of wildlife; location of recreational, historic, and archeological sites; and the possible effects of air, noise, and water pollution. - Economic, including unit costs for construction and the trend of agricultural, commercial, and industrial activities. ## 2-Reconnaissance Survey - Identify several feasible routes using aerial photographs and taking into consideration factors such as: - Terrain and soil conditions. - Serviceability of route to industrial and population areas. - Crossing of other transportation facilities, such as rivers, railroads, and highways. - Directness of route. ## 3-Preliminary Location Survey - During this phase of the study, Feasible routes are set as closely as possible and preliminary vertical and horizontal alignments determined. - Preliminary alignments are used to evaluate the economic and environmental feasibility of the alternative routes. #### a-Economic Evaluation - Economic evaluation of each alternative route is carried out to determine the future effect of investing the resources necessary to construct the highway. Factors usually taken into consideration include: - Road user costs - Construction costs - Maintenance costs - Road user benefits #### b-Environmental Evaluation - Construction of a highway have a significant impact on its surroundings environments including plant, animal, and human communities. ## 4-Final Location Survey - The final location survey is a detailed layout of the selected route. - The horizontal and vertical alignments are determined, and the positions of structures(bridges, tunnels etc.) and drainage channels are located. - Set out of points of intersection (PI) of straight portions of the highway and fit horizontal curves between them. ## Location of Highways in Urban Areas - Urban areas usually present complex conditions that must be considered in the highway location process. - In addition to factors discussed under office study and reconnaissance survey, other factors that significantly influence the location of highways in urban areas include: - Connection to local streets. - Right-of-way acquisition (Cost). - Coordination of the highway system with other transportation systems. - Adequate provisions for bicycles pedestrians. ## Highway Survey Method - Highway surveys usually involve measuring and computing horizontal and vertical angles, vertical heights (elevations), and horizontal distances. - the surveys are then used to prepare base maps with contour lines (that is, lines on a map connecting points that have the same elevation) and longitudinal cross-sections. - Surveying techniques can be grouped into three general categories: - Ground surveys - Remote sensing - Computer graphics ## Modes of Transportation 1. **Road Transportation** - Highway (Road) - Rail Transportation 2. **Air Transportation** - Domestic - International 3. **Water Transportation** - Inland water (boats, launches, barges, streamers, etc.) - Ocean (ships) 4. **Hyperloop Transportation** - Hyperloop is a proposed new mode of transportation that moves quickly, safely, on-demand and direct from origin to destination. Hyperloop will see individual low capacity (28-40 people) magnetically levitated pods propelled at high speeds (760 mph) through an extreme low pressure (100 Pascal's), low friction environment contained within a tube system. - It consists of a sealed tube or tubes in which pods will travel without any air resistance or frictional resistance. - It is given name hyper loop because it travels in a loop. ## Road Transport ### Advantages of Road Transport 1. It is a relatively cheaper mode of transport as compared to other modes. 2. Perishable goods can be transported at a faster speed by road carriers over a short distance. 3. It is a flexible mode of transport as loading and unloading is possible at any destination. It provides door-to-door service. 4. It helps people to travel and carry goods from one place to another, in places which are not connected by other means of transport like hilly areas. ### Limitations of Road Transport 1. Due to limited carrying capacity road transport is not economical for long distance transportation of goods. 2. Transportation of heavy goods or goods in bulk by road involves high cost. 3. It is affected by adverse weather conditions. Floods, rain, landslide, etc., sometimes create obstructions to road transport. ## Rail Transport ### Advantages of Rail Transport 1. It is a convenient mode of transport for travelling long distances. 2. It is relatively faster than road transport. 3. It is suitable for carrying heavy goods in large quantities over long distances. 4. Its operation is less affected by adverse weathers conditions like rain, floods, fog, etc. ### Limitations of Railway Transport 1. It is relatively expensive for carrying goods and passengers over short distances. 2. It is not available in remote parts of the country. 3. It provides service according to fixed time schedule and is not flexible for loading or unloading of goods at any place. 4. It involves heavy losses of life as well as goods in case of accident. ## Water Transport ### Advantages of Water Transport 1. It is a relatively economical mode of transport for bulky and heavy goods. 2. It is a safe mode of transport with respect to occurrence of accidents. 3. The cost of maintaining and constructing routes is very low as most of them are naturally made. 4. It promotes international trade. ### Limitations of Water Transport 1. The depth and navigability of rivers and canals vary and thus, affect operations of different transport vessels. 2. It is a slow moving mode of transport and therefore not suitable for transport of perishable goods. 3. It is adversely affected by weather conditions. 4. Sea transport requires large investment on ships and their maintenance. ## Air Transport ### Advantages of Air Transport 1. It is the fastest mode of transport. 2. It is very useful in transporting goods and passengers to the area, which are not accessible by any other means. 3. It is the most convenient mode of transport during natural calamities. 4. It provides vital support to the national security and defense. ### Limitations of Air Transport 1. It is relatively more expensive mode of transport. 2. It is not suitable for transporting heavy and bulky goods. 3. It is affected by adverse weather conditions. 4. It is not suitable for short distance travel. 5. In case of accidents, it results in heavy losses of goods, property and life. ## Hyperloop Transportation ### Merits 1. Faster 2. There is no problem of traffic. 3. It is powered by the solar panel. 4. It can travel in any kind of weather. 5. Pollution free. 6. Lower cost. 7. Safer. 8. More convenient. 9. Resistance to earthquake. ### Demerits 1. Turning will be critical. 2. Less movable space for passenger. 3. High speed might cause dizziness in some passenger. 4. Punctured tunnel could cause shockwaves. ## Transportation Organizations ### Federal Agencies - U.S. Department of Transportation (US DOT) - Federal Aviation Administration (FAA) - Federal Highway Administration (FHWA) - Federal Railway Administration (FRA) - National Highway Traffic Safety Administration (NHTSA) - Federal Transit Administration (FTA) - Federal Motor Carrier Safety Administration (FMCSA) ### State and Local Agencies and Authorities - State department of transportation (KDOT) - Counties (Douglas County Engineer's Office) - Cities (Lawrence City Management) - Township ## Trade Associations - Association of American Railroads (AAR) - American Road and Transportation Builders Association (ARTBA) - American Public Transit Association (APTA) - American Bus Association (ABA) - Asphalt Institute (AI) - Portland Cement Association (PCA) Professional Organizations: - American Society of Civil Engineers (ASCE) - American Association of State Highway and Transportation Officials (AASHTO) - Institute of Transportation Engineers (ITE) - Intelligent Transportation System (ITS) America - Transportation Research Board (TRB)