Civil Engineering Past Paper PDF

Basic Engineering Sciences (CIV1008) Itgalpur, Rajanukunte, Yelahanka, Bengaluru – 560064 DEPARTMENT OF CIVIL ENGINEERING CIV1008...

Basic Engineering Sciences (CIV1008) Itgalpur, Rajanukunte, Yelahanka, Bengaluru – 560064 DEPARTMENT OF CIVIL ENGINEERING CIV1008 – Basic Engineering Sciences Module 1: Introduction to various fields in Civil Engineering 1.1 Civil Engineering: It is the first basic branch of engineering. Its relation to the fulfillment of human needs is direct, whereas the other engineering branches are complementary to the function of civil engineering. Civil engineering is called the general engineering because civil engineering uses the principles and information provided by other branches of engineering while erecting civil engineering structures. Civil Engineering is a professional engineering discipline that deals with the planning, design, construction, operation, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings. 1.2 Role of Civil Engineers: ❖ Providing shelter to people in the form of low-cost houses to high rise apartments ❖ Laying ordinary village roads to express highways ❖ Constructing irrigation tanks, multipurpose dams, canals for supplying water to agricultural fields ❖ Supplying safe and potable water for public industrial uses ❖ Protecting our environment by adopting sewage treatment solid waste disposal techniques ❖ Constructing hydro-electric thermal power plants for generating electricity ❖ Providing other means of transportation such as railways, harbour and airports ❖ Constructing bridges across streams, rivers and across seas ❖ Tunneling across mountains also under water to connect places easily reduce distance 1.3 Fields of Civil Engineering Civil engineering is a very broad discipline that incorporates many activities in various fields. The different fields of civil engineering and the scope of each can be briefly discussed as follows: 1. Structural Engineering Structural engineering deals with the analysis & design of various components of a civil engineering structure. Any civil engineering structure has several components, for e.g., a building has components like slabs, beams, columns & foundation. Analysis deals with estimating the loads, forces & stresses on the component. Design deals with selecting an appropriate material & deciding suitable dimensions for the structural component such that they resist the loads safely without failure. It is also important to ensure that the design is economical as well. 2. Transportation Engineering Transportation Engineering involves planning, design, construction & maintenance of the basic 1  Basic Engineering Sciences (CIV 1008) facilities or infrastructure required for transportation systems. The transport system includes roadways, railways, air & waterways. Role of civil engineers in this field is to construct and maintain roads, expressways, bridges, flyovers, bus terminals, railway tracks, runways, ports & harbours. It also includes planning the systems and facilities to optimal capacity keeping with future growth andexpansion needs. 3. Geotechnical Engineering All structures are constructed on top of the earth. Any building, bridge, dam, retaining wall etc. rests on soil and is supported by soil. The foundation connects the structure & soil. The foundation transfers load from the structure to the soil. The foundation is laid at a certain depth below the ground surfacetill a hard layer is reached. The soil should be thoroughly checked for its suitability for construction purposes. The study dealing with the engineering properties & behaviour of soil under loads &changes in environmental conditions is called geo-technical engineering. 4. Surveying Surveying is the science and art of determining the relative position of points on the earth’s surface by measuring distances, directions and vertical height. It is the first step before any construction activity is commenced. Surveying helps in preparing maps and plans, which help in project implementation (setting out the alignment for a road or railway track or canal, deciding the location for a dam or airport or harbour). Surveying also helps in estimating quantities of earth-fill, excavations and thus also aids in estimating cost of project. 5. Environmental Engineering Environmental Engineering deals with the protection & maintenance of the natural and built environment. It includes monitoring and maintaining the quality of air & water, monitoring and management of waste disposal. It also includes providing water supply for domestic, industrial and commercial needs along with providing sewage disposal facilities and this part of environmental engineering is known as Water Supply and Sanitary Engineering. 6. Building Materials & Construction Technology Management Any engineering structure requires a wide range of materials for construction. The choice of material depends upon the purpose of application, aesthetics, suitability for the particular application & most importantly its cost. The efficiency or success of any construction project depends on the management of materials, manpower, machinery & money. Hence, management is an inevitable part of any construction activity. The different activities should be planned properly; the manpower, materials & machinery should be optimally utilized, so that the construction is completed in time and in an economical manner. 7. Hydraulics Engineering, Water resources & Irrigation Engineering This field of civil engineering deals with managing the water resources (rivers, ground water) of the country. It also deals with the process of supplying water by artificial means to fields for raising crops. This is a very important activity for a country like India with scanty rainfall & very few perennial rivers. This branch deals with the construction & maintenance of dams for storage of water and canal 2  Basic Engineering Sciences (CIV 1008) networks for conveying water. Apart from these, other associated structures like canals regulators, aqueducts, weirs, barrages etc. are required for a proper irrigation system. The facilities for Hydro- electric power generation also come under the purview of this branch. 8. Architecture and town planning Architecture is the art and science of designing and constructing buildings and other physical structures. Key aspects of architecture include: Design, Materials, Structure, Functionality, Sustainability, and Aesthetics. Town planning (or urban planning) involves the design and regulation of the use of space within urban areas. It focuses on: Land Use, Infrastructure, Transportation, Public Spaces, Housing, Sustainability, Economic Development, and Community Involvement. The integration of architecture and town planning ensures that individual buildings fit harmoniously within their urban context, creating functional, sustainable, and aesthetically pleasing environments. 9. Remote Sensing & GIS The improvement in space technology, availability of GPS enhanced the scope of geographic information system. Good mapping technique helps to get required information accurately and quickly to effectively manage and monitor the available resources for optimal use. GIS is an high-tech equivalent of map. It represents a means to locate ourselves in relation to world around us. It deals with measurement, mapping, monitoring and modeling of geographic information around us. 1.4 Overview of Structural Engineering: A structure may be defined as an assemblage of load-bearing elements in a construction. Man-made structures include buildings, towers, bridges and dams (civil engineering structures) and Aircraft, ships, oil rigs, cranes, cars and furniture (Aeronautical / mechanical engineering). Structural analysis is the application of solid mechanics to predict the response in terms of forces and displacements of a given structure (existing/proposed) subject to specified loads. Structural Engineering deals with planning of positions/layout of different elements and design (determination of size, shape and material) of component such that safety and serviceability requirements are not sacrificed, yet economy is considered. Repair, rehabilitation and maintenance are parts of structural engineering. Dams, Bridges, Stadiums, Auditoriums, Multi-storied buildings are analyzed & designed structurally. 1.4.1 Type of Structures: Framed Structures: In framed structure, the load transfer mechanism is from Floor slab to the Beams in the floor then to the columns and Foundation system. Load bearing Structures: In load bearing structure, the load transfer mechanism is directly from floor slab to the adjoining walls and then to the foundation system. 3  Basic Engineering Sciences (CIV 1008) 1.4.2 Differences between Framed and Load bearing Structure Framed Structures Load Bearing Structures Load transfer path is from slab/floor to Load transfer path is from slab/ floor to wall, beam,beam to column and column to wallto footing. footing. Limited storey buildings can only be Multi storey buildings can be constructed. constructed. Framed structure is more resistant to lateral Load bearing structure is less resistant to loadsdue to earthquake and wind. lateralloads due to earthquake and wind. Carpet area available is more. Carpet area available is less. Mostly used form of construction. Rarely used form of construction nowadays. Excavation for this type of construction is Excavation for this type of construction is more. less. The speed of construction is more. The speed of construction is less. Cost of repair of framed structure is more. Cost of repair of load bearing structures is less. Skilled as well as non-skilled Skilled work force is required for workercan construct load bearing structures. construction. The thickness of wall can be maintained The thickness of wall cannot be maintained uniformthroughout. uniform throughout. It is flexible in design as location of It is not flexible in design as walls cannot walls canshifted. beremoved/shifted. Room dimensions cannot be changed as Room dimension can be changed. wallshave to be placed above walls below. In load bearing structure, large span areas In framed structure, large span areas notpossible. possible. Load Bearing walls can be of Brick, The frame can be RCC, Steel, Wood frame Stone,concrete block etc. etc. Large openings in walls are possible. Limitations for openings in walls. 1.4.3 Components of a Building Slab Beam Column Walls Foundation Slab: Slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs, bridges, and other types of structures. The slab may be supported by walls, by reinforced concrete beams usually cast monolithically with the slab, by structural steel beams, by columns, or by the ground. Beam: A beam is a horizontal member and resists externally applied loads essentially by bending (or flexure). Beams can also be referred to members, elements, rafters, shafts, or purlins. Beams may be in a wide range of cross-sectional shapes depending on their different applications and strength purposes. 4  Basic Engineering Sciences (CIV 1008) Some common shapes are I beams, T-beams, channel sections, rectangular, hollow rectangular and pipes. Column: Columns are vertical structural members which resist the external load primarily by axial compression and sometimes both axial force and bending (when it is part of frame element) in case of lateral loads such as wind and earthquake loads. Its capacity depends upon its geometry, material, and the effective length of the column, which depends upon the restraint conditions at the top and bottom of the column. Walls: Walls are used to divide or enclose in building construction, to form the periphery of a room or a building. In traditional masonry construction, walls support the weight of floors and roofs (i.e., load bearing structure). Modern steel and reinforced concrete frames, as well as heavy timber and other skeletal structures, require exterior walls for shelter (i.e., Framed Structure). Footings: Footings are structural elements that transmit column or wall loads to the underlying soil below the structure. Footings are designed to: transmit the loads to the soil without exceeding its safe bearing capacity prevent excessive settlement of the structure to a tolerable limit Minimize differential settlement Prevent sliding and overturning 1.4.4 Bridges A bridge is a structure which provides a safe passage for a road or railway track over obstacles, without closing the obstacle below. The obstacle to be crossed may be a river or stream, a canal, road or a railway track. A bridge may also be built for the safe passage of a canal (aqueduct). A bridge helps to connect difficult terrains, enables easy trade and transportation of goods and helps reduce travelling time. Bridges have political & economic importance in addition to its use for military. Components of a bridge The components of a bridge are mainly grouped into: a. Super Structure – Portion of the bridge above the bearing b. Sub Structure – Portion of the bridge below the bearing Deck Slab: Deck is bridge floor directly carrying traffic loads. Deck transfers loads to the Girders depending on the decking material. Girder: Girder/Beam is the part of superstructure which is under bending along the span. It is the load bearing member which supports the deck slab. Bearings: Bearings transfers loads from the girders to the pier caps. Bearing is a component which supports part of the bridge and which transmits forces from one part to another part of the structure while permitting angular and/or linear movement between parts. 5  Basic Engineering Sciences (CIV 1008) Bed Blocks: Bed block rests over the top of the piers & abutments is generally provided to evenly distribute the dead and live loads on the pier and abutments. They are usually made up of Reinforced Cement Concrete. Abutments: Abutments are vertical structures used to retain the earth behind the structure. The dead and the live loads from the bridge superstructure is also supported by the bridge abutments. Piers: Pier is a part of the substructure which supports the superstructure and which transfers loads coming on the superstructure to the foundations. Depending up on aesthetics, site, space and economic constraints various shapes of piers are adopted to suit to the requirement. Mostly Reinforced Concrete or pre-stressed concrete are adopted for the construction of piers Foundation: Foundation is the component which transfers loads from the substructure to the bearing strata. Depending on the geotechnical properties of the bearing strata, shallow or deep foundations are adopted. Usually, piles and well foundations are adopted for bridge foundations. 1.4.5 Classification of Bridges 1. Based on Materials used Concrete Bridge Steel Bridge Timber Bridge Composite Bridge 2. Based on the purpose Road Bridge Rail Bridge Rail & Road Bridge Pedestrian Bridge Aqueduct 3. Based on Span Culvert < 6m Minor Bridge 6m-60m Major Bridge > 60m 4. Based on Alignment Straight Skew 5. Based on Structural action Beam bridges Cable stayed bridges Suspension bridges Cantilever bridge Truss bridge Arch bridge 6  Basic Engineering Sciences (CIV 1008) 1.5 Introduction to Soil Mechanics & Geotechnical Engineering Soil Mechanics: Soil Mechanics is the application of laws of mechanics and hydraulics to engineeringproblems dealing with soil as an engineering material. It deals with properties, behavior and performance of soil as a construction material orfoundation support The soil should be thoroughly checked for its bearing capacity and suitability for construction purposes. Objectives of Foundation To distribute the load from the structure to soil evenly and safely To anchor the building to the ground so that under lateral loads building will not move To prevent the building from overturning due to lateral forces To give level surface for the construction of super structure Factors affecting Foundation Soil types and ground water table conditions. Structural requirements. Construction requirements. Site condition and environmental factors Economy. 1.5.1 Types of Foundations Foundations are mainly classified into two groups based on the 1. Shallow Foundations 2. Deep Foundation Shallow Foundation A shallow foundation is one whose depth is generally less than the width of the footing and less than 3m. Shallow foundations are located just below the lowest part of the wall or a column which they support. They are used when the surface soils are strong enough to support the load imposed upon it. Footing is a structural member, which is the bottom most part of a foundation made of brick work, masonry or concrete. Footings are used to transmit the load of the wall or column such that the load is distributed over a large area. Types of Shallow Foundation Shallow Foundations are classified into the following types: 1. Strip Footing / Strip Foundation 2. Spread or Isolated Footing / Spread Foundation 3. Combined Footing / Combined Foundation 4. Mat or Raft Foundations 7  Basic Engineering Sciences (CIV 1008) 1. Strip Footing: A strip footing is provided for a load-bearing wall. A strip footing is also provided for a row of columns which are so closelyspaced that their spread footings overlap or nearly touch each other. A strip footing is also known as continuous footing. 2. Spread or Isolated Footing: A spread (or isolated or pad) footing is provided to support an individual column. A spread footing is circular, square or rectangular slab of uniform thickness. Sometimes, it is stepped or hunched to spread the load over a large area. 3. Combined Footing: A combined footing usually supports two columns. It is used when the two columns are so close to each other that their individual footings would overlap. A combined footing is also provided when the property line is so close to one column that a spread footing would be eccentrically loaded when kept entirely within the property line. A combined footing may be rectangular or trapezoidal in plan. 4. Mat or Raft Foundation: A mat or raft foundation is a large slab supporting a number of columns and walls under the entire structure or a large part of the structure. A mat is required when – a) the allowable soil pressure is low or where the columns and walls are so close that individual footings would overlap. Mat foundations are useful in reducing the differential settlements. Deep Foundation When the soil at or near the ground surface is not capable of supporting a structure, deep foundations are required to transfer the loads to deeper strata. Deep foundations are, therefore, used when surface soil is unsuitable for shallow foundation and a firm stratum is so deep that it cannot be reached economically by shallow foundations. Types of Deep Foundation The deep foundations are of the following types 1. Pile Foundation 2. Pier Foundation 3. Caisson Foundation 8  Basic Engineering Sciences (CIV 1008) 1. Pile Foundation: A pile is a slender column made of wood, concrete or steel. A pile is either driven into the soil or formed in situ by excavating a hole and then filling it with concrete. A group of piles are driven to the required depth and are capped with R.C.C. Slab, over which super structure is built. The pile transfers the load to soil by friction or by direct bearing. 2. Pier Foundations: A pier is a vertical column of relatively larger cross- section than piles. A cast in-situ pile greater than 0.6 m diameter is generally termed as a pier. Piers have large diameter as compared to a pile. For walls carrying heavy loads, piers are dug at regular intervals and filled with plain concrete. The piers are taken up to good bearing strata. The piers are connected by concrete or masonry arch. 3. Caisson Foundation: A caisson is a hollow prismatic watertight box or chamber, which is built above the ground level and then sunk to the required depth as a single unit. It is a watertight chamber used for laying foundations under water, as in rivers, lakes, harbors. The caisson subsequently becomes an integral part of the foundation. 1.6 Transportation Engineering Transportation engineering is the science of safe and efficient movement of people and goods. Transportation contributes to the economic, industrial, social and cultural development of any country. Transportation is vital for the economic development of any region since every commodity produced, whether it is food, clothing, agricultural products, industrial products or medicine, needs transportation at all stages from production to distribution. In the production stage, transportation is required for carrying raw material like seeds, manure, coal, steel oil etc. In the distribution stage, transportation is required from the production centers, namely farms and factories to the marketing centers and later to the retailor and consumers for distribution. Modes of Transportation: The four major modes of transportation are: 1. Roadways or highways 2. Railways 3. Airways 4. Waterways Transport by air is the fastest among the four modes. Air travel also provides more comfort apart from the saving in transportation time for the passengers 9  Basic Engineering Sciences (CIV 1008) and goods between the airports. Transportation by water is the slowest mode among all the modes but it is the economical mode of transport. Transportation by water is possible between ports on the sea routes or along rivers or canals where inland transportation facilities are available. 1. Roadways or highways Classification of Road: Sectional view of Divided National Highway Road Elements Pavement Camber Kerb Shoulders Medians Pavement: A highway pavement is a structure consisting of superimposed layers of processed materials above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade. The ultimate aim is to ensure that the transmitted stresses due to wheel load are sufficiently reduced, so that they will not exceed bearing capacity of the sub-grade. Camber: Camber is a transverse slope provided to the road to drain off surface water. Camber depends on type of rainfall and pavement. Excessive camber causes transverse tilt of vehicle. Kerb: Kerb is a boundary between pavement and footpath or median. It remarkets the road boundary and provide lateral support to the pavement. Shoulders: 10  Basic Engineering Sciences (CIV 1008) Shoulder is an extra space provided to the road to use an emergency lane. Shoulder is much rougher than road so that it can’t be used as a regular traffic lane. Median: Function of median is to segregate the traffic in opposite direction, avoid head on collision and reduce the gleaming effect due to the headlight at night. 2. Railway engineering: Railway engineering is a multi-faceted engineering discipline dealing with the design,construction and operation of all types of rail transport systems. Rails: Rails are the members of the track laid in two parallel lines to provide an unchanging, continuous, and level surface for the movement of trains. To be able to withstand stresses, they are made of high-carbon steel. They carry out the function of transmitting the load to a large area of the formation through sleepers and the ballast. Sleepers: Sleepers are the transverse ties that are laid to support the rails. They have an important role in the track as they transmit the wheel load from the rails to the ballast. Sleepers hold the rails in their correct gauge and alignment. It also helps in transferring the load evenly from the rails to a wider area of the ballast. Ballast: Ballast is a layer of broken stones, gravel, moorum, or any other granular material placed and packed below and around sleepers for distributing load from the sleepers to the formation. It provides drainage as well as longitudinal and lateral stability to the track. Formation (Subgrade): Subgrade is the naturally occurring soil which is prepared to receive the ballast. The prepared flat surface, which is ready to receive the ballast, along with sleeps and rails, is called the formation. The formation is an important constituent of the track, as it supports the entire track structure. 3. Airport Engineering: Airport Engineering encompasses the planning, design, and construction of terminals, runways, and navigation aids to provide for passenger and freight service. An airport is a facility where passengers connect from ground transportation to air transportation. It is a location where aircraft such as airplanes, helicopters take off and land. 11  Basic Engineering Sciences (CIV 1008) Aircraft may also be stored or maintained at an airport. An airport should have runway for takeoffs and landings, buildings such as hangars and terminal buildings. Runway orientation is important in airport planning. Current practice is to layout a runway in the direction of prevailing wind. Runways may be a man-made surface (often Bitumen, concrete, or a mixture of both) or a natural surface (grass, dirt, gravel, ice, or salt). Components of Airport 1. Runway: “Rectangular area on an airport used for landing and take-off” Runway orientation is important in airport planning. Current practice is to lay out a runway in the direction of prevailing wind. Runways may be a man-made surface (often Bitumen, concrete, or a mixture of both) or a natural surface (grass, dirt, gravel). 2. Terminal buildings: These buildings are the spaces where passengers board or alight from flights. These buildings house all the necessary facilities for passengers to check-in their luggage, clear the customs and have lounges to wait before disembarking. It can house cafes, lounges and bars to serve as waiting areas for passengers. Ticket counters, luggage check-in or transfer, security checks and customs are the basics of all airport terminals. Large airports can have more than one terminal that are connected to one another through link ways such as walkways, sky-bridges or trams. Smaller airports usually have only one terminal that houses all the required facilities. 3. Apron Portion of the airport usually provided in front of TB, means for parking, loading/unloading of aircraft, refueling. It is paved area for parking of aircraft Loading and unloading of passengers and cargo. Usually located near to the terminal building or hanger. They vary in size, from areas that may hold five or ten small planes, to the very large areas that the major airports have. Unlike the runways or taxiways, vehicles can use aprons. It is typically more accessible to users than the runway or taxiway. Apron portion is not managed by air traffic control (ATC). 4. Taxiway: These are defined as the paths on the airfield surface for the taxing of aircraft and are intended to provide linkages between one part of the airfield and another. Hence on the taxiways aircrafts move only on the ground and there is no air movement associated and the movement is relatively slow. They mostly have hard surface such as Bitumen or concrete, although smaller airports sometimes use gravel or grass. 5. Aircraft Stand: An aircraft stand is a place where an aircraft can be parked. It is part of the apron 6. Hangar: A hangar is a closed building structure to hold aircraft or spacecraft. 12  Basic Engineering Sciences (CIV 1008) Hangars are used for protection from the weather, direct sunlight and for maintenance, repair, manufacture, assembly and storage of aircraft. 7. Control Tower: A tower at an airfield which air traffic is controlled by radio and observed physically and by radar. 8. Parking: Parking is a specific area of airport at which vehicles park. 1.7 Hydraulics, Water resources and Irrigation Engineering Hydraulics deals with mechanics of water (fluid) flow Hydraulics is further classified into Fluid Statics, Fluid kinematics and Fluid Dynamics 1.7.1 Key Applications of hydraulics in Civil Engineering Water Supply and Distribution: Engineers use hydraulic principles to design pipelines, reservoirs, and distribution networks that ensure a reliable and efficient supply of water to urban and rural areas. Hydraulic Structures: Construction of hydraulic structures like Dams, weirs, and spillways serve various purposes, including water storage, hydroelectric power generation, flood control, and irrigation. Stormwater and Flood Management: Hydraulics helps design drainage systems, levees, flood barriers, and retention basins particularly in regions prone to heavy rainfall or coastal areas by controlling and channelizing water flow, reducing the risk of flooding. Irrigation and Agricultural Hydraulics: Design canals, pumps, and distribution networks that efficiently deliver water to crops, optimizing water use and supporting sustainable agriculture. Modern irrigation systems, such as drip and sprinkler systems, are designed to minimize water waste and improve crop yields, reflecting the growing importance of hydraulic efficiency in agriculture. Environmental Hydraulics: The protection and restoration of natural water bodies, such as rivers, lakes, and wetlands, are increasingly important in civil engineering. 1.7.2 Water resources engineering Water resource engineering deals with identification & utilization of available water resources minimizing the loss. This also deals with ground water utilization, ground water recharge (Natural and Artificial) and rain water harvesting. Not all natural freshwater, surface water or groundwater, is accessible for use. The available water resources consider factors such as: the economy, environmental feasibility and Physical possibility of catching water which naturally flows out to the sea. Sources of water 1. Surface sources: Lakes, Ponds, Rivers, Streams, Storage reservoir. 13  Basic Engineering Sciences (CIV 1008) 2. Subsurface sources: Open wells, Tube wells, Artesian wells, Springs, Infiltration gallery. Artesian well: When a well is driven into a confined aquifer where water is flowing in confinement with pressure, the well is called as an Artesian well. Pump is not required. This can be understood by a water supply scheme fed by an over-head tank. Infiltration gallery: A tunnel constructed at shallow depth along the bank of a river through the water bearing strata, to collect water seeping through the bottom, these are constructed by masonry work. Springs: Springs generally emerge at the base of a hillslope. Springs represent places where the saturated zone (below the water table) comes in contact with the land surface. 1.7.3 Irrigation Engineering It deals with water management for agriculture purpose. Irrigation is the science of artificial application of water to the agricultural field in accordance with crop requirements throughout the period of growth for full maturity of crop. Advantages Increase in food production Insuring optimum growth or maximum yield Mixed cropping Generation of hydropower Improving domestic water supply Disadvantages Over irrigation may cause water logging which can reduce crop yield. Over irrigation combined with fertilizers & pesticides can lead to increase in nutrient level of nearby lakes and rivers leading to Eutrophication and may also cause groundwater contamination. Irrigation may lead to creation of climatic condition which favourable for public health diseases. 1.7.4 Dam and its purposes A dam is a physical obstruction constructed across a river to store the water in reservoir and divert it for multipurpose from its upstream side. The pool of water form on the upstream side of the dam, is called as the reservoir of the dam. Purpose of Construction of Dams: Power generation: Hydroelectric power is a major source of electricity in the world Many countries have rivers with adequate water flow that can be dammed for power generation purposes. Water supply: Many urban areas of the world are supplied with water abstracted from rivers pent up behind low dams or weirs. Other major sources include deep upland reservoirs contained by high dams across deep valleys. Stabilize water flow/irrigation: Dams are often used to control and stabilize water flow, often for 14  Basic Engineering Sciences (CIV 1008) agricultural purposes and irrigation. Flood prevention: Dams that are created for flood control Land reclamation: Dams are used to prevent ingress of water to an area that would otherwise be submerged, allowing its reclamation for human use. Water diversion Dams: that are constructed for diverting water for various purposes Recreation Dams: built for any of the above purposes may find themselves displaced by the time of their original use Nevertheless, the local community may have come to enjoy the reservoir for recreational and aesthetic reasons Components of a Dam structure Heel: contact with the ground on the upstream side. Toe: contact on the downstream side. Abutment: Sides of the valley on which the structure of the dam rest. Galleries: small rooms like structure left within the dam for checking operations. Diversion tunnel: Tunnels are constructed for diverting water before the construction of dam. This helps in keeping the river bed dry. Spillways: It is the arrangement near the top to release the excess water of the reservoir to downstream side Sluice way: An opening in the dam near the ground level, which is used to clear the silt accumulation in the reservoir side Classification of Dams 1. Based on Material Earthen Dam Masonry Dam Steel Dam Concrete Dam 2. Based on Structural behavior Gravity Dam Buttress Dam Arch dam Embankment Dam 3. Based on Functionality Storage Dam Diversion Dam Detention Dam Coffer Dam Check Dam 15  Basic Engineering Sciences (CIV 1008) 1.8 Environmental Engineering Environment is the available nature around us. It includes the life support system such as water, air and land/Soil. Environmental engineering deals with the technology to save nature from human and natural abuse and pollution. The study involves balanced compromise between environment and safety. Environmental Engineering primarily deals with: Technique of water collection, purification and supply Waste water collection, treatment and disposal Control of all types of pollution 1.8.1 Objectives of Water treatment Removal of floating suspended matter. Improvement in the aesthetic quality of water by removing unpleasant taste and odour. Removal of settleable suspended matter and non-settleable colloidal impurities. Removal of dissolved mineral matter, colour and bacteria. Softening of water for use in domestic washing laundries and boilers. Making the water non-corrosive, suitable for industrial processing, and recreational uses. 1.8.2 Water Quality parameters Water Quality Parameters can be divided into three types 1. Physical Parameters Suspended solids – Sense of Sight Turbidity – Sense of Sight Colour – Sense of Sight Odour and taste – Sense of Smell and Taste Temperature – Sense of Touch 2. Chemical Parameters Total Dissolved solids Alkalinity pH Hardness Nitrogen content Chloride content Fluoride content Different gases Metals DO, COD, BOD 3. Biological Parameters Bacteriological aspects Virologic aspects 16  Basic Engineering Sciences (CIV 1008) Parasitological aspects Algae 1.8.3 Drinking Water Standards as per IS 10500: 2012 Sl. No. Parameter Permissible Limit 1 pH 6.5 to 8.5 2 Conductivity 1.5 ms/cm 3 Turbidity 1 to5 NTU 4 Acidity 120 mg/l 5 Total Alkalinity 200 mg/l 6 TDS 500 to 2000 mg/l 7 Total Hardness 300 to 600 mg/l 8 Calcium as Ca 75 to 200 mg/l 9 Magnesium as Mg 30 to 100 mg/l 10 Chlorides 250 mg/l 11 Sulphates 150 mg/l 12 Dissolved Oxygen (DO) 4 to 5 mg/l 13 Biological Oxygen Demand (BOD) 0 mg/l 1.8.4 Water treatment process/units and functions 17  Basic Engineering Sciences (CIV 1008) 1.8.5 Waste Water Wastewater is liquid waste, often produced as the byproduct of many uses of water. Household uses Industrial uses Commercial uses Agricultural uses Livestock uses Terminologies in Waste Water Sewage: Mixture of water and liquid waste generated due to different activities in the community. Domestic sewage: Liquid waste generated due to domestic household activities. Industrial waste water: Waste generated due to industrial activity. Sanitary sewage: Mixture of domestic and industrial sewage. Sewers: Pipes or conduits required to carry the sewage from one point to another point. Sewerage system: The entire process of collecting, treating, and disposing of sewage. Waste water quality parameter Dissolved oxygen (DO): It refers to the amount of oxygen gas that is dissolved in water. Low levels of DO can indicate poor water quality and can be harmful to aquatic life. Chemical Oxygen Demand (COD): It is a measure of the amount of oxygen required to chemically oxidize organic and inorganic compounds in water. Biochemical Oxygen Demand (BOD): It is a measure of the amount of oxygen that microorganisms require to break down organic matter in a water sample over a specific period of time. Waste water treatment unit Screening: Screening is the preliminary stage where large floating objects and debris are removed from the raw wastewater. Grit Chamber: It is designed to remove grit, sand, gravel, and other heavy inorganic particles from the wastewater stream. Primary Treatment – This stage of wastewater treatment involves the removal of large matter from wastewater through sedimentation and filtration. Secondary treatment – It is a biological process that uses bacteria to remove impurities from water. Tertiary Treatment – It removes the persistent pollutant (after secondary treatment) by various physical and chemical process. 18