Highway And Railroad Engineering PDF

HIGHWAY AND RAILROAD ENGINEERING  ROAD HIGHWAY AND RAILROAD ENGINEERING Different modes Conclusion Highway Alignment of Transportation Scope of Highway Engineering Road Patterns and...

HIGHWAY AND RAILROAD ENGINEERING  ROAD HIGHWAY AND RAILROAD ENGINEERING Different modes Conclusion Highway Alignment of Transportation Scope of Highway Engineering Road Patterns and Planning Surveys Design Criteria for Highways route definition ❖Roads are generally constructed on small embankments, slightly above the general ground level, to avoid difficult drainage and maintenance problems. What is ❖Such roads are therefore termed highways, and the science and technology dealing with roads are HIGHWAY generally engineering. called highway ENGINEERING? Scope of HIGHWAY ENGINEERING HIGHWAY GEOMETRIC 1 DEVELOPMENT 6 DESIGN AND LOCATION PAVEMENT 2 PLANNING 7 DESIGN CONSTRUCTION 3 ALIGNMENT 8 AND MAINTENANCE HIGHWAY ECONOMIC 4 MATERIAL 9 CONSIDERATION TRAFFIC FINANCIAL AND 5 CONTROL 10 ADMINISTRATION  DEVELOPMENT, Historical Background, the basis for PLANNING, AND planning, master plan, engineering surveys, and highway alignments. LOCATION MATERIALS, Highway material and mix design, highway construction, earthwork, construction of different CONSTRUCTION, AND types of pavements, WBM, pavement failure, pavement evaluation, maintenance of pavements MAINTENANCE HIGHWAY DESIGN, Road geometrics and design, rigid and GEOMETRICS, AND flexible pavement, design factors and thickness, and drainage system design. STRUCTURE ECONOMICS, Road user cost and economic analysis of highway FINANCES, AND projects, pavement types and maintenance measures, and highway finance ADMINISTRATION Traffic studies analysis, need for new road TRAFFIC PERFORMANCE links, traffic regulation and control, AND ITS CONTROL intersection design and their controls with signs, signals, and markings Scope of HIGHWAY ENGINEERING Major modes ROADWAYS OR HIGHWAYS WATERWAYS AIRWAYS MODES OF TRANSPORTATION RAILWAYS  ❖ Road patterns refer to the layout or arrangement of What is streets, lanes, and thoroughfares within a city or town. ROAD PATTERN? ❖ These patterns play a crucial role in shaping the flow of traffic, pedestrian movement, and overall accessibility. ROAD PATTERN  types RECTANGULAR/ HEXAGONAL BLOCK PATTERN ROAD PATTERN Types of The area is divided into a Hexagonal pattern is a ROAD PATTERN rectangle or block- network of roadways that form a hexagonal shape. Three shaped plots to create a roads intersect with the rectangle or block constructed region at each pattern. corner of the hexagon.  Pros & cons RECTANGULAR/BLOCK PATTERN ADVANTAGES DISADVANTAGES To construct back-to-back This pattern is inconvenient buildings with front-facing since the roads are roadways, the rectangular perpendicular at junctions, plots may be further divided causing the traffic to into smaller rectangular blocks. ROAD Construction and converge towards a single maintenance of highways point. using this design are relatively simpler. PATTERN  Pros & cons HEXAGONAL ROAD PATTERN ADVANTAGES DISADVANTAGES Travel time and distance There should be enough are cut down. traffic signs, pavement Reduced traffic congestion markings, and illumination to alert vehicles to lower ROAD their travel speed and minimize the risk of accidents. PATTERN  MINIMUM TIME types TRAVEL PATTERN The town is served by sector centers, suburban facilities, and neighborhood centers in this road plan, all of which are connected to the city center by a highway that can be reached in the shortest amount of time. Also, the shortest roads interconnect the city center GRID PATTERN with neighboring and suburban centers. The alignment of the road A network of intersecting parallel Types of is made straight to shorten it. lines, real or imaginary, is referred to as a grid. When seen from above, this ROAD PATTERN pattern is made up of streets that connect at right angles to form squares. A physical network not always constructed of straight or parallel lines may also be called a grid.  Pros & cons MINIMUM TIME TRAVEL PATTERN ADVANTAGES DISADVANTAGES The potentially dangerous The right amount of traffic collisions are almost signs, pavement markings, eliminated. and illumination should be in place to alert vehicles to ROAD slow down. For senior drivers, intersections may be particularly difficult. PATTERN  Pros & cons GRID PATTERN ADVANTAGES DISADVANTAGES Grids benefit pedestrians Grids are dangerous for motorists and bicycles because since there are several they contain numerous routes from point A to junctions and many potential point B. conflict places. ROAD Grids benefit restaurants Grids may encourage individuals to take shortcuts and retail establishments through residential areas. since they provide Grids don't work well in places several corner lots. with many hills since they result A grid's navigation is in unnecessarily steep streets. PATTERN Traffic mayhem may readily quite simple. occur on a grid that is uneven or unfinished. RADIAL road pattern Radial or Star and Radial or Star and Radial or Star and Grid pattern Block pattern Circular pattern This type of road network combines radial This network is a combination of radial and This kind of road network combines radial and block road patterns. The whole area circular road patterns. It is a road pattern in and grid patterns. From the center, a is arranged into a block-pattern road which the major roadways, or radial roads, radial network of roads radiates outward. network that runs between the radial radiate outward from the center and are The grid pattern is then used to main streets and radiates outward from joined by the ring roads, or concentric roads, interconnect the main radial streets. the center. which likewise radiate outward. TYPES OF ROAD PATTERN  Pros & cons RADIAL OR STAR & GRID PATTERN ADVANTAGES DISADVANTAGES It increases the There should be sufficient effectiveness of land usage distance between splitter unit density. islands. It has a high percentage of High construction cost for ROAD 3-way intersections, offering additional traffic lights and great vehicle safety. road markings. Cut-through traffic is reduced. PATTERN  Pros & cons RADIAL OR STAR & BLOCK PATTERN ADVANTAGES DISADVANTAGES Safer when compared to a Lack of safety equipment rectangular pattern. such as post-support bases, It reduces congestion at crash attenuators, and rail the main bottleneck point. transitions. ROAD If one radial route is closed, another may be utilized as an alternative. PATTERN  Pros & cons RADIAL OR STAR & CIRCLE PATTERN ADVANTAGES DISADVANTAGES Compared to the Its design is complex, and it isn't abovementioned patterns, it is easy to provide a decent curve. safer since all the traffic moves It impacts driving abilities (most drivers experiencing this issue are in the same direction. senior citizens). This traffic plan includes ROAD The appropriate installation of roundabouts, which enhances traffic signals, road markings, and traffic flow. Additionally, this illumination is required to alert the lowers the vehicle's fuel driver. consumption. Splitter islands must be made long Lowers the chances of rear- enough to include a crosswalk and a roundabout description end collisions. PATTERN  types HORIZONTAL VERTICAL ALIGNMENT ALIGNMENT road comprises a series consists of straights of straight lines known as connected by parabolic Types of tangents with the provision of curves to change direction curves, which need to be provided at all changes in gradient ALIGNMENT  AVAILABILITY OF OBLIGATORY POINTS CONSTRUCTION TRAFFIC MATERIALS The controlling points Should suit traffic which govern the For bringing down the requirements, highway alignment are cost of construction Origin and destination known as obligatory and maintenance cost studies should be points. it is important to have carried out and It is divided into two easy availability of desired line should be parts, points through natural building drawn. which the alignment material. The new roads aligned should pass and points should keep in view through which the desired line, traffic alignment should not patterns, and future pass. trends. FACTORS AFFECTING ROAD ALIGNMENTS  ECONOMIC GEOLOGICAL LAND CROSSING FACTOR FACTOR AQUISITION Availability of land The provision of The alignment Alignment for the construction stream crossing, finalized based on should be made of the highway is all factors should in such a way river crossing necessary, also be and railway that no serious If alignment should economical. be such that crossing along The initial cost, the difficulties are considerable built- the road maintenance cost, met from the up area and alignment vehicle operating geological point cultivated land should be cost should be of view of the area are to be properly studied. taken into locality, e.g. acquired, it will account. earthwork, prove to be difficult, costly and time- landslides. consuming. FACTORS AFFECTING ROAD ALIGNMENTS PLANNING SURVEYS ❖A highway should be planned according to the volume of daily traffic flow from a OBJECTIVE particular path. For this purpose, a proper survey must be done to collect adequate data. ❖The highways development must be efficient, but at a minimum cost, especially in developing and underdeveloped countries. ❖The highways should be safe and secure. ❖The planning must have a forecast for the next several years to plan fixed periods for maintenance, renewal, and widening. OBJECTIVE  Possible alignment can be fixed based on the following details available on the map : Any Alignment passing through valleys, lakes, and ponds. Location of bridges for crossing rivers. Availability of a mountain passing a mountain range. Joining of two stations at different elevation by taking a suitable ruling gradient. Determination of the length of the roadway TYPES OF using contour interval and ruling gradient. HIGHWAY PLANNING SURVEYS MAP SURVEY  The purpose of the reconnaissance survey is to eliminate those routes or sites that are impractical or unfeasible and to identify the more promising routes or sites. OBJECTIVE OF RECONNAISSANCE SURVEY Collect the details of obstruction along the route which are not available on the map. e.g. valleys, ponds, lakes, marshy land, ridge, hills, permanent structure, etc. To collect geological features of the field. To collect information regarding the availability of local construction material, water, and labor. To determine the approximate values of a gradient, TYPES OF length of gradients and radius of curves of alternate alignments. To locate the obligatory points along the alternative HIGHWAY PLANNING routes. To determine an approximate estimate of the total cost of construction of the road along each route. SURVEYS To determine two or three best possible routes. RECONNAISSANCE STUDY  Type of survey in which adequate data is collected to prepare a plan/map of the area to be used for planning and design. OBJECTIVE OF PRELIMINARY SURVEY To survey along the various alignments found after the reconnaissance and to collect all necessary physical information and details of topography, drainage, and soil. To compare the different proposals given the requirements of good road alignment. To estimate the cost of constructing the road TYPES OF including bridges and other construction aspects along each alternative alignment of the road. HIGHWAY PLANNING To finalize the best alignment from the construction, maintenance, and traffic operation point of view. SURVEYS PRELIMINARY SURVEY  The detailed examination of the field along the alignment finally recommended during the preliminary survey OBJECTIVE OF PRELIMINARY SURVEY The alignment finalized at the design office after the preliminary survey is to be first located on the field by establishing the centerline. A detailed survey should be carried out to collect the information necessary for the TYPES OF preparation of plans and construction HIGHWAY PLANNING details for the highway project. To determine the cost of the total road project. SURVEYS LOCATION SURVEY  SOIL AND MATERIAL DRAINAGE TRAFFIC SURVEYS SURVEYS SURVEY Traffic surveys are started from simple traffic counts Detailed information on Drainage surveys are to details of traffic nature various classifications of required mainly for the and transportation studies. soils is collected and purpose of design of Various studies like speed studies, traffic volume various field tests and cross-drainage structures studies, delays, and laboratory test are and survey on drainage journey time are essential being carried out for the is quite useful in fixing the to carry out for the purpose of their gradient or grade lien of purpose of road design suitability for the road. and also the improvement embankments. of the existing road network. ENGINEERING SURVEYS  Type of highway planning surveys which consist of determining the horizontal and vertical locations of objects on the surface of the earth. Topographic surveys show the nature of the ground or profile of ground which is the most essential part for proper road alignment. TYPES OF HIGHWAY PLANNING SURVEYS TOPOGRAPHIC SURVEYS  CONSISTENCY Making every element of the roadway conform to the expectations of every driver. Drivers expect the highway agency to provide them with: Clear information and guidance through a variety of road signs. Avoiding abrupt changes in the traffic as well as the road standards. If these guides and directions could be planned properly to convey one single message at a time, and if these directions will be followed smoothly and easily without undue haste, or speed changes, then, the roadway facilities are considered satisfactory. HIGHWAY DESIGN CRITERIA  DESIGN SPEED No single set of Geometric Standards will apply to all highways. For every highway segment, decisions regarding appropriate control for each of the many details or requirements must be addressed individually or separately. The high-speed road design must anticipate future generations of high-speed vehicles and advanced transportation systems that may operate on many road alignments. HIGHWAY DESIGN CRITERIA  DESIGN SPEED Although the design speed of most highways is governed by construction costs, the concept of the relatively high-speed design for freeways is Regardless of Cost. They are planned for a nationwide high- volume traffic and high-speed network. HIGHWAY DESIGN CRITERIA  SPEED IMPLICATIONS Research shows that lower speeds lead to fewer and less serious crashes. There are two reasons for this: At higher speeds a rider or a driver has less time to react to a situation and therefore there is a greater likelihood that an error will result in a crash; and The momentum and kinetic energy of a vehicle increases rapidly with speed. The sudden dissipation of this energy in a crash means that the injury to occupants is more severe. Therefore, a carefully planned speed limit regime can make a significant contribution to road safety. HIGHWAY DESIGN CRITERIA  SPEED IMPLICATIONS 40 kph (High-risk pedestrian areas) appropriate for roads where there are no footpaths and pedestrians are required to walk on the road. 60 kph (Low-risk pedestrian areas) On roads through built-up areas where there are not so many pedestrians. It is appropriate to allow motorized traffic to travel more quickly. HIGHWAY DESIGN CRITERIA  SPEED IMPLICATIONS 80 kph Appropriate on a high standard duplicated carriage road where there is only occasional access from adjoining properties. 100 kph Appropriate on very high standard expressways, which have a low crash rate. These expressways should have a high standard geometry and should be free of roadside hazards. HIGHWAY DESIGN CRITERIA  SPEED RESTRICTION SIGNS Good speed management practice depends on speed limit signs being placed in visible locations and repeated frequently enough for motorists to be certain of which speed zone they are in. HIGHWAY DESIGN CRITERIA  POOR ROAD STANDARDS If the standard of the road geometry or its surface is poor, then it may be appropriate to adopt a lower speed limit than would normally apply until such time that the road improvements can be made. The lower speeds compensate for the hazardous conditions of the road. HIGHWAY DESIGN CRITERIA  ROAD CAPACITY It is the maximum number of vehicles, which have a reasonable expectation of passing over a given section of a lane or a roadway in one direction or in both directions during one hour under prevailing road and traffic conditions. Factors affecting the capacity of a route: Number of Lanes Side friction such as the Lane and shoulder width presence of road furniture Terrain and road gradient and pedestrians Traffic composition Intersection capacity (priority and movements, traffic signal phasing, number of lanes, etc.) HIGHWAY DESIGN CRITERIA  ROAD TYPES The basic functional types of roads are locals, collectors, arterials, and freeways. Major considerations in the classification of highway functional types: Land use Mobility Local streets – emphasizes access with little consideration for mobility Freeways – emphasizes mobility with limited access Collectors – emphasizes access Arterials – emphasizes mobility HIGHWAY DESIGN CRITERIA  DESIGN VEHICLES The highway designer should exercise his judgment in selecting the appropriate design vehicle for design control, based on the intended use of the facility. General classes of Design Vehicles: Passenger Cars Trucks Buses Recreational vehicles The passenger car category includes sport utility vehicles, minivans, vans, and pickup trucks. The bus and truck categories include buses and trucks of all sizes, respectively. HIGHWAY DESIGN CRITERIA  DRIVER’S CHARACTERISTICS The geometric design of a highway should consider users, especially drivers' performance limits. There are limits to a driver's vision, perception, reaction, concentration, and comfort that could impact highway safety and operating efficiency. When driving, most drivers receive information visually from their views of the roadway alignment, markings and signs. They do receive other information through vehicle feedback from the suspension system and steering control, and roadway noise. HIGHWAY DESIGN CRITERIA  NUMBER OF LANES The number of lanes in a segment of the highway is determined from the estimated traffic volume for the design year (AADT) and highway lane capacity at expected level of service. AASHTO policies accept a dually divided 16 lanes roadway with four lanes in each direction for an inner freeway and four more lanes in each direction on the outside. There are some instances where a reversible lane is located at the center of freeways with unbalanced heavy traffic flow HIGHWAY DESIGN CRITERIA  LEVEL OF SERVICE CONSIDERATION Given a fixed volume of traffic flow and vehicle composition, the geometric design of highways, such as the horizontal and vertical curves, grades, lane width, number of lanes, etc., affects the travel speed of vehicles and the interaction between vehicles. The outcome of such an effect is the observable operational performance of the highway, qualitatively represented by the highway level of service. The concept of LOS and methods of evaluation for different highway types are covered in great detail in the Highway Capacity Manual (TRB 2000). HIGHWAY DESIGN CRITERIA THANK YOU FOR LISTENING!