2. HIGHWAYS DEVELOPMENT AND PLANNING..pdf

HIGHWAY DEVELOPMENT AND PLANNING HISTORICAL DEVELOPMENT OF ROAD CONSTRUCTION EARLY DEVELOPMENT ▪ The oldest mode of transportation was on foot paths, or by the use of animals. Later on after the invention of wheels, man developed different kinds of carriages to accommodate the needs for a more c...

HIGHWAY DEVELOPMENT AND PLANNING HISTORICAL DEVELOPMENT OF ROAD CONSTRUCTION EARLY DEVELOPMENT ▪ The oldest mode of transportation was on foot paths, or by the use of animals. Later on after the invention of wheels, man developed different kinds of carriages to accommodate the needs for a more comfortable mode of transportation. ▪ This development lead to the construction of hard surfaces for roads. Such hard surfaces is believed to have existed in Mesopotamia, about 3500 B.C. The first roads with authentic records existed during the Assyrian empire, about 1900 B.C. ▪ It was the Roman Empire that built roads in large scales and with the earliest construction techniques, these roads will be later known as the Roman Roads, earning the name as the pioneer in road construction. ROMAN ROADS ▪ Many of these Roman roads used elaborate construction, some even surviving after over 2000 years. It has been calculated that these network of roads that the Romans built covered a distance of over 400,00 km, with more than a 120,000 km of these roads being the type known as the "public roads". ▪ This network of roads allowed the empire to quickly move from one point to another, and allowed the transportation of the goods from their different colonies to another. Roman roads consisted of three layers - a foundation at the bottom, middle layer, and a surface layer on top. ▪ These layers were consisted of different kinds of rocks and stone slabs to ensure that the roads will last, even with the relatively low magnitude of wheel loads of that time. The main features of Roman Roads are: ▪ built straight regardless of the gradient. ▪ built after the soft soil was removed and a hard stratum was reached. ▪ total thickness of construction was as high as 0.75 to 1.2 meters at some places TRESAGUET CONSTRUCTION ▪ Not until the eighteenth century did any early civilizations have created a new road construction method, Pierre Tresaguet developed an improved method of construction in France. He developed several methods of construction. The main feature of his proposal was that the thickness of the roads need not to be over 30 cm. The typical cross section of Tresaguet Construction : ▪ ▪ subgrade is prepared and a layer of large foundation stones were laid on edge by hand. At the two edges of pavement large stones were embedded edgewise to serve as submerged curb stones. ▪ the corners of these heavy foundation stones were hammered and then the interstices filled with smaller stones. Broken stones were packed to a thickness of about 8 cm and compacted. ▪ Top wearing course was made of smaller stones and compacted to a thickness of about 5 cm at the edges and gradually increased towards the center, giving a cross slope of 1 in 45 to the surface. ▪ The shoulders were also provided cross slope to drain the surface water to the side drain METCALF CONSTRUCTION ▪ John Metcalf (1717-1810) was engaged on road construction works in England during the same period as Tresaguet when he was working in France. He was responsible for the construction of the 290 km of road in the northern region of England. TELFORD CONSTRUCTION ▪ Thomas Telford began his work in the early 19th century. He was the founder of the Institution of Civil Engineers at London. He believed in using heavy foundation stones below the top surface and above soil subgrade. The construction steps are: ▪ A level subgrade is prepared to the designed width of about 9 meters. ▪ Large foundation stones of thickness 17-22 cm were laid with hand with their largest face down so as to be in stable position. Stones with 17 cm thickness were laid at the edges and increases towards the center at 22 cm. ▪ The interstices between the foundation stones were filled with smaller stone and chipping and properly beaten down. ▪ The central portion of about 5.5 meter width was covered with two layers of angular broken stones to compacted thickness of 10 and 5 cm. ▪ A certain width of the pavement towards the edges was constructed by compacted broken stones, 15cm thick, sometimes in lime mortar instead of using the curb stones. ▪ A binding layer of wearing course 4 cm thick was constructed on top using gravel MACADAM CONSTRUCTION ▪ John Macadam put forward an entirely new method of road construction. He was the Surveyor General of Roads in England and his new concept of road construction became known by the year 1827. He recognized the importance of subgrade drainage and compaction. He also suggested that heavy foundation stones are not at all necessary to be placed at the bottom layer of construction. The most important modifications made in Macadam's methods with respect to the older methods are: ▪ ▪ the importance of subgrade drainage and compaction were recognized and so the subgrade was compacted and was prepared with a cross slope of 1 in 36. ▪ Macadam was also the first person to suggest that heavy foundation stones are not at all necessary to be placed at the bottom layer. ▪ though the total thickness of construction was less than the previous methods, this technique could serve the purpose in better way, due to better load dispersion characteristics of compacted broken stone aggregates of smaller sizes. ▪ The size of broken stones for the top layer was decided based on the stability under animal drawn vehicles. MACADAM'S METHOD IS THE FIRST METHOD BASED ON SCIENTIFIC THINKING. IT WAS REALIZED THAT STRESSES DUE TO THE WHEEL LOADS OF TRAFFIC DECREASES ON THE LOWER PART OF THE PAVEMENT. THIS METHOD BECAME VERY POPULAR FAR AND WIDE. VISUAL PRESENTATION OF 3 MOST POPULAR ROADS AFTER THE ROMAN EMPIRE CLASSIFICATION OF ROADS TYPES OF ROADS 1. classified depending on whether they can be used all throughout the year; ▪ all-weather roads ▪ fair weather roads 2. All weather roads are roads that are fairly manageable to use during all weather, except at major river crossing where interruption to traffic is permissible upon certain extent; 2. Classified based on the type of carriage or the road pavement, the roads are classified as; ▪ paved roads - provided with a hard pavement course which should be at least a water bound macadam layer ▪ unpaved roads - earth roads, gravel roads 3. classified based on the type of pavement surfacing provided ▪ surface roads - provided with bituminous or cement concrete surfacing ▪ unsurfaced roads - not provided with bituminous or cement concrete surfacing -ROADS MAY ALSO BE CLASSIFIED BASED ON THEIR USE, AS CLASSIFIED BY THE DPWH FOR ROADS IN THE PHILIPPINES 1. NATIONAL PRIMARY ROADS ▪ directly connects major cities of at least 100,000 people (cities in the metro not included) ▪ The national primary roads are roads which form parts of the main trunkline system and directly connect three or more major cities and metropolitan areas with a population of at least 100,000. They are further classified into the north–south backbone, east–west lateral, and other roads of strategic importance. ▪ The north–south backbone refers to the main trunkline, the Pan-Philippine Highway (N1, also designated as Asian Highway 26), which runs from Laoag in the northernmost parts of Luzon to Zamboanga City in western Mindanao, interconnecting the country's major islands. The east–west lateral roads are roads that traverse this backbone and runs east–west across the different islands. Other roads of strategic importance provide access to other areas vital for regional development and infrastructure. ▪ Also known as Maharlika Highway 2. NATIONAL SECONDARY a. Directly connects Cities to National Primary Roads, except in Metropolitan Area b. Directly connects Major Ports and Ferry Terminals to National Primary Road c. Directly connects Major Airports to National Primary Road d. Directly connects Tourist Service Centers to National Primary Roads or other- e. Directly connects Cities (not included in the category of Major Cities) f. Directly connects Provincial Capitals within the same Region g. Directly connects to Major National Government Infrastructure to National Primary h. Roads or Other National Secondary Roads 3. NATIONAL TERTIARY ▪ Other existing roads under DPWH which perform a local function 4. PROVINCIAL ROADS (LOCAL ROADS) ▪ a. Connect Cities and Municipalities without traversing National Roads b. Connect National Roads to Barangays through rural areas c. Connect to Major Provincial Government Infrastructure 5. MUNICIPAL AND CITY ROADS (LOCAL ROADS) ▪ a. Roads within the Poblacion b. Roads that connect to Provincial and National Roads c. Roads that provide Inter-Barangay connections to Major Municipal and City Infrastructure without traversing Provincial Roads 6. BARANGAY ROADS (LOCAL ROADS) ▪ Other Public Roads (officially turned over) within the Barangay and not covered in the above definitions. 7. EXPRESSWAYS ▪ Highways with limited access, normally with interchanges; may include facilities for levying tolls for passage in an open or closed system. BYPASSES ▪ are roads or highways that avoid a built-up area, town or city proper to let through traffic flow without interference from local traffic reduce congestion and improve road safety where a toll for passage is levied in an open or closed system. ROAD PATTERNS ▪ - different road patterns may be classified to: ▪ ▪ (a) rectangular or block pattern ▪ (b) radial or star and block pattern ▪ (c) radial or star and circular pattern ▪ (d) radial or star and grid pattern ▪ (e) hexagonal pattern PLANNING SURVEYS ▪ Highway planning includes the assessment for the length requirement for an area (maybe a district, city, or the whole country) and preparation of master plan. In doing these phases, one must carry out field surveys and collect data. The field surveys required to collect the data may be called as planning surveys. ▪ The planning surveys consist of the following fact finding surveys: a. economic studies - population, trend of its growth, agricultural and industrial listing, income per capita, banking, post office, etc., b. financial studies - source of income, revenue from taxation on road transport c. traffic or road use studies - traffic volume, traffic flow patterns, mass transportation facilities, accidents, growth of vehicular traffic, passenger trips d. engineering studies - road location and alignment, classification; type of roads in use, soil and topography studies HIGHWAY ALIGNMENT ▪ The position or the layout of the center line of the highway on the ground is called alignment. Horizontal alignment includes the straight path, horizontal deviations and the curves. Changes in gradient and vertical curves are under vertical alignment. It is important that the roads must be properly aligned and adheres to road standards for the failure to do these would result to increase in; construction cost, maintenance cost, vehicle operation cost, accident rate. ▪ Requirements for and Ideal Alignment ▪ short ▪ easy ▪ safe, and ▪ economical FACTORS CONTROLLING ALIGNMENT ▪ For the road to be shortest, the best would be for it to be straight line from point A to point B but, due to several challenges that the engineers might encounter on the site, it may not be feasible. The various factors which control the highway alignment in general might be listed as: ▪ obligatory points ▪ traffic ▪ geometric design ▪ economics ▪ other considerations; special considerations while aligning roads on hilly areas ▪ stability ▪ drainage ▪ geometric standard of hill roads ▪ resisting length Activity 2: 1.Explain how Roman roads survived the passage of time. 2.Find two cities that use different road patterns and explain their advantages and disadvantages from each other.