Introduction to Geotechnical Engineering

The term geo means earth or soil. This means it has something to do with the earth. Geotechnical engineering is an area of civil engineering that focuses on the engineering behaviour of earthen materials; or Geotechnical engineering, also known as geotechnics, is a discipline within civil engineering that focuses on the behavior of natural geological materials in engineered systems. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It also relies on knowledge of geology, hydrology, geophysics and other related sciences. Geotechnical engineers recognize that soil and rock are the cheapest and most abundant building materials on earth, and consequently play a major role in the construction and performance of every type of civil engineering structure.

Geotechnical engineering is the study of the behaviour of soils under the influence of loading forces and soil-water interactions. This knowledge is applied to the design of foundations, retaining walls, earth dams, clay liners and geosynthetics. The goals of geotechnical engineers could range from the design of foundations and temporary excavation support, through route selection for railways and highways, to the increasingly important areas of landfill disposal of wastes and groundwater contamination. As such, the geotechnical engineer is involved in field and laboratory investigations to determine the engineering properties of site soils and other geomaterials and their subsequent use in the analytical study of the problem at hand.

As well as civil engineering, geotechnical engineering is also used in fields such as coastal engineering, offshore construction projects, mining, military and petroleum. While the fields of geotechnical engineering and engineering geology have overlapping areas of expertise, engineering geology is closely tied to geology while geotechnical engineering is aligned to civil engineering. Geotechnical engineers use their knowledge to determine the chemical, mechanical and physical properties of soil and rock for the design of earthworks, foundations and retaining structures. A site investigation of ground conditions is used to determine the depth of foundations, while earthworks may include embankments, channels, bunds and tunnels and retaining structures include retaining walls and earth-filled dams. Furthermore, if there are issues with the foundation, then the entire structure is in trouble. Therefore, geotechnical engineers play a critical role in every constructed project.

Until about the last 100 years geotechnical engineering was largely empirical and based on observation and careful reflection. Remarkable scientific advancement in this specialty within civil engineering has been achieved in the post-World War II era and continues today with the aid of high-performance computers, sensors, data visualization and advanced soil testing. Geotechnical engineering relies on the continuous application of engineering judgment. This judgment can be best developed by careful study of past successes and failures, and years of experience.

Every civil engineering structure and its construction is related to soil in some way, and subsequently, its design will depend on properties of the soil or rock. Geotechnical operations are of importance with respect to soil sampling, investigating geomaterial properties, controlling groundwater level and flow as well as environmental and hydrological interactions. Foundation engineering, excavations and supporting ground structures, underground structures, dams, natural or artificial fills, roads and airports, subgrades and ground structures, and slope stability assessments are examples of geotechnical engineering applications.

Despite notable progress in geotechnical engineering, many solutions are still approximate, which is mainly due to the non homogeneity of soils and dominant environmental conditions. Additionally, soils are more sensitive to local environmental conditions compared to other prefabricated building materials such as steel or concrete. Consequently, it would be necessary to have comprehensive understanding of natural soil deposits, environment interactions and response to local conditions to allow more accurate prediction of geomaterials engineering performance and behavior in projects.

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Introduction to Structural Analysis

A structure comprises several components that are connected to one another and function to transfer the loads to the soil successfully. The structure is a collection of elements linked together in such a way that serves a meaningful purpose. Thus, a structure is an arrangement and organization of interrelated elements in an object or system, with the load affecting structural components vertically or laterally. Different types of structures are concrete, framed, shell, membrane, truss, cables and arches, surface structure, etc. 

In other terms “structure” refers to a building or any other artificial object designed to support a load in construction. Structures can be made of various materials such as wood, steel, concrete or brick and can range from simple structures such as a shed or fences to complex structures such as bridges, skyscrapers or dams. 

Structural engineering is the field of engineering that deals with the design, analysis and construction of structures. A properly designed and constructed structure must resist various forces and loads such as gravity, wind, earthquakes and other external factors to ensure the safety of the structure.

Structural analysis is the prediction of the performance of a given structure under prescribed loads and/or other external effects, such as support movements and temperature changes. The performance characteristics commonly used in the design of structures are

1. Stress or stress resultant, such as axial force, shear force and bending moment
2. Deflection
3. Support reaction

Thus, the analysis of a structure usually involves determination of these quantities as caused by a given loading condition. 

History of Structural Engineering

Since the dawn of history, structural engineering has been an essential part of human endeavor. However, it was not until about the middle of the seventeenth century that, engineers began applying the knowledge of mechanics (mathematics and science) in designing structures. Earlier engineering structures were designed by trial and error and by using rules of thumb based on past experience. The fact that some of the magnificent structures from earlier eras, such as Egyptian pyramids (about 3000 BC), Greek temples (500–200 BC), Roman coliseums and aqueducts (200 BC–AD 200), and Gothic cathedrals (AD 1000–1500), still stand today is a testimonial to the ingenuity of their builders.

Galileo Galilei (1564–1642) is generally considered to be the originator of the theory of structures. In his book entitled ‘Two New Sciences’, which was published in 1638, Galileo analyzed the failure of some simple structures, including cantilever beams. Although Galileo’s predictions of strengths of beams were only approximate, his work laid the foundation for future developments in the theory of structures and ushered in a new era of structural engineering, in which the analytical principles of mechanics and strength of materials would have a major influence on the design of structures.

Following Galileo’s pioneering work, the knowledge of structural mechanics advanced at a rapid pace in the second half of the seventeenth century and into the eighteenth century. Among the notable investigators of that period were Robert Hooke (1635–1703), who developed the law of linear relationships between the force and deformation of materials (Hooke’s law); Sir Isaac Newton (1642–1727), who formulated the laws of motion and developed calculus; John Bernoulli (1667–1748), who formulated the principle of virtual work; Leonhard Euler (1707–1783), who developed the theory of buckling of columns; and C. A. de Coulomb (1736–1806), who presented the analysis of bending of elastic beams. In 1826 L. M. Navier (1785–1836) published a treatise on elastic behavior of structures, which is considered to be the first textbook on the modern theory of strength of materials.

The development of structural mechanics continued at a tremendous pace throughout the rest of the nineteenth century and into the first half of the twentieth, when most of the classical methods for the analysis of structures described in this text were developed. The important contributors of this period included B. P. Clapeyron (1799–1864), who formulated the three-moment equation for the analysis of continuous beams; J. C. Maxwell (1831–1879), who presented the method of consistent deformations and the law of reciprocal deflections; Otto Mohr (1835–1918), who developed the conjugate-beam method for calculation of deflections and Mohr’s circles of stress and strain; Alberto Castigliano (1847–1884), who formulated the theorem of least work; C. E. Greene (1842–1903), who developed the moment-area method; H. Muller-Breslau (1851–1925), who presented a principle for constructing influence lines; G. A. Maney (1888–1947), who developed the slope-deflection method, which is considered to be the precursor of the matrix stiffness method; and Hardy Cross (1885–1959), who developed the moment-distribution method in 1924.

The moment-distribution method provided engineers with a simple iterative procedure for analyzing highly statically indeterminate structures. This method, which was the most widely used by structural engineers during the period from about 1930 to 1970, contributed significantly to their understanding of the behavior of statically indeterminate frames. Many structures designed during that period, such as high-rise buildings, would not have been possible without the availability of the moment-distribution method. The availability of computers in the 1950s revolutionized structural analysis. Because the computer could solve large systems of simultaneous equations, analyses that took days and sometimes weeks in the precomputer era could now be performed in seconds.

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Surveying

Surveying is the process of determining the relative position of natural and man made features on or under the earth’s surface, the presentation of this information either graphically in the form of plans or numerically in the form of tables and the setting out of measurements on the earth’s surface. It usually involves measurement, calculations, production of plans and the determination of specific locations. The profession of a surveyor is to determine the heights and distances for setting out buildings, bridges and roadways, to determine areas and volumes and to draw plans at a predetermined scale.

Surveying is defined as “the art and science of determining the relative positions of various points or stations on the surface of the earth or above or below the surface of earth by measuring the horizontal and vertical distances and angles.” These details are used for preparing map or plan to any suitable scale.

Surveying is also defined as “taking a general view of, by observation and measurement, determining the boundaries, size, position, quantity, condition, value etc. of land, estates, building, farms mines etc. and finally presenting the survey data in a suitable form”. This covers the work of the valuation surveyor, the quantity surveyor, the building surveyor, the mining surveyor as well as the land surveyor.

Objective of Surveying

The object of surveying is to prepare a map or plan to show the relative positions of the objects on the surface of the earth. The map or plan is drawn to some suitable scale. It also shows boundaries of districts, states countries too. It features different engineering works like buildings, roads, railways, dams, canals etc.

Uses of Surveying

The surveying may be used for following purposes:

• To prepare a topographical map which shows hills, valleys, rivers, forests, villages, towns etc.
• To prepare a cadastral map which shows the boundaries of fields, plots, houses and other properties
• To prepare an engineering map which shows the position of engineering works such as buildings, roads, railways, dams, canals etc.
• To prepare a contour map to know the topography of the area to find out the best possible site for roads, railways, bridges, reservoirs, canals etc.
• To prepare military map, geological map, archaeological map etc.
• For setting out work and transferring details from the map on the ground
• To determine facts on the size, shape, gravity and magnetic fields of the earth
• To prepare charts of moon and planets
• To prepare map the earth above and below sea level
• To prepare navigational carts for use in the air, on land and at sea
• To establish property boundaries of private and public lands
• To develop data banks of land-use and natural resources information which aid in managing the environment

Process of Surveying 

1) Taking a general view

It is important as it indicates the need to obtain an overall picture of what is required before any type of survey work is undertaken. In land surveying, this is achieved during the reconnaissance study.

2) Observation and Measurement

It denotes the next stage of any survey, which in land surveying constitutes the measurement to determine the relative position and sizes of natural and artificial features on the land.

3) Presentation of Data

The data collected in any survey must be presented in a form which allows the information to be clearly interpreted and understood by others. This presentation may take the form of written report, bills of quantities, datasheets and drawings, and in land surveying maps and plan showing the features on the land.

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Concrete

Concrete is the most versatile and most widely used construction material worldwide and it is the most commonly used man-made material on earth. A composite material that consists essentially of a binding medium, such as a mixture of portland cement and water, within which are embedded particles or fragments of aggregate, usually a combination of fine and coarse aggregate. It is an important construction material and is used extensively in buildings, bridges, roads, dams etc. It can be engineered to satisfy a wide range of performance specifications, unlike other building materials, such as natural stone or steel, which generally have to be used as they are. Because the tensile strength of concrete is much lower than its compressive strength, it is typically reinforced with steel bars, in which case it is known as Reinforced Cement Concrete (RCC).

Fresh concrete or plastic concrete is a freshly mixed material which can be moulded into any shape. The relative quantities of cement, aggregates and water mixed together, control the properties of concrete in the wet state as well as in the hardened state.

History of Concrete

Roman Concrete

As in modern construction, the Romans used wooden formworks and cast the concrete into them. Often, forms were built up using stone or brick. In tall structures, dense stone was used as aggregate at the bottom and light stone was used higher up.

Advantages

• It was strong and easier to use than stone for making smooth shapes (such as domes)
• It could set under water, so it could be used for piers and pediments of bridges and aqueducts

Disadvantages

• It takes a long time (up to a year) to reach high strength (so structures can sag before hardening)
• The raw materials (viz., volcanic ash) are not widely available

After the fall of Rome, concrete technology was lost in Western Europe until the 19th century. In 1756, John Smeaton was commissioned to build the Eddystone Lighthouse off the Cornwall coast (England). Contemporary mortars would not set under water, so he experimented with various local limestones. When limestone containing clay was fired, the resulting lime gained strength under water. In 1824, Joseph Aspdin patented Portland cement (so named because it was said to resemble Portland stone - a high quality limestone quarried near Portland). It is made byfiring clay and limestone (but at too low a temperature). In 1845, Isaac Johnson made the type of cement now known as Portland cement.

Uses of concrete

Many structural elements like footings, columns, beams, chejjas, lintels, roofs are made with RCC and it is used for making storage structures like water tanks, bins, silos, bunkers, bridges, dams, retaining walls etc.

Benefits of concrete

• It is a relatively cheap material and has a relatively long life with few maintenance requirements. It is strong in compression
• Before it hardens it is a very pliable substance that can easily be shaped
• It is non-combustible

Limitations of concrete

The limitations of concrete include:

• Relatively low tensile strength when compared to other building materials
• Low ductility
• Low strength-to-weight ratio
• It is susceptible to cracking

Ingredients of Concrete

• Cement
• Water
• Fine Aggregate
• Coarse Aggregate
• Admixtures

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Introduction to Engineering Mechanics

Mechanics is that branch of physical science which deals with the action of forces on material bodies or it is defined as the branch of science, which describes and predicts the conditions of rest or motion of bodies under the action of forces. Engineering mechanics applies the principle of mechanics to design, taking into account the effects of forces. It deals with the practical applications of mechanics in the field of engineering. Applications of Engineering Mechanics are found in the analysis of forces in components of roof truss, bridge truss, machine parts, parts of heat engines, rocket engineering, aircraft design etc. 

Mechanics is the study of forces that act on bodies and the resultant motion that those bodies experience. With roots in physics and mathematics, engineering mechanics is the basis of all the mechanical sciences: civil engineering, materials science and engineering, mechanical engineering, biomedical engineering and aeronautical and aerospace engineering. It plays an important role in designing and analyzing many mechanical systems, such as aircraft, automobiles, bridges, buildings, machinery, pipelines, ships, satellites, and spacecraft. Engineering Mechanics provides the “building blocks” of statics, dynamics, strength of materials, and fluid dynamics. It is the discipline devoted to the solution of mechanics problems through the integrated application of mathematical, scientific, and engineering principles. 

Divisions of Engineering Mechanics 

The subject of Engineering Mechanics may be divided into the following two main groups: Statics and Dynamics.

1) Statics 

It is the branch of engineering mechanics, which deals with the forces and their effects, while acting upon the bodies at rest. 

2) Dynamics 

It is the branch of engineering mechanics, which deals with the forces and their effects, while acting upon the bodies in motion. Dynamics may be further sub-divided into the following two branches: Kinetics and Kinematics

a) Kinetics 

It is the branch of dynamics which deals with the forces and its effect on bodies in motion along with forces causing motion. 

b) Kinematics 

It is the branch of dynamics which deals with the forces and its effect on bodies in motion without considering the forces causing motion.

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Introduction to Engineering Graphics

Graphics is a term derived from the Greek word “Graphikos” which means the art or science of drawing of an object on a two-dimensional surface according to mathematical rules of projection. 

Engineering drawing is a two dimensional representation of three dimensional objects. In general, it provides necessary information about the shape, size, surface quality, material, manufacturing process etc. of the object. It is the graphic language from which a trained person can visualize objects. Engineering graphics is the art of manipulation of designs of a variety of components, especially those related to engineering. It primarily consists of sketching the actual component, for example, a building or machine, with its exact dimensions and using entities such as points, lines, arcs etc. The scale of dimensions is suitably adjusted so as to properly fit within the contours of the drawing sheet.

Drawing Instruments and Aids

The Instruments and other aids used in drafting work are listed below:

• Drawing board
• Set squares
• French curves
• Templates
• Mini drafter
• Instrument box
• Protractor
• Set of scales
• Drawing sheets
• Pencils 

The three most necessary techniques of drawing/projection are: 

1) Orthographic Projection 

In this method the object is placed in space in such a way that the front view of it is captured in the vertical plane, and the top view of the same, is captured in the horizontal plane. The projections of the object are perpendicular with the planar screen. 

2) Perspective Projection 

This is a simple technique of drawing an object as how one views it. The observer's eye position, height and distance from the object, all influence the outcome of the drawing. Two sub-methods are adopted for this projection technique, namely, Visual Ray Method and Vanishing Point Method. 

3) Isometric Projection

This form of projection gives the total detail of the component under consideration. The basic principle behind isometric projection is that it involves the consideration of three axes that are inclined to each other making equal angles with each other (120°). This is followed by transfer of actual dimensions to the isometric scale involving some basic trigonometric calculations. 

Engineering drawing plays a vital role both in manufacture and design, as it not only explains the string of arrangement in a machine, but also tells us about the method to be employed to manufacture the individual blocks. An engineering drawing not only helps to convey ideas and convert concepts into reality but also follows criteria and conventions to eliminate confusion to the individual who understand when it is read, and very importantly, it indicates how something is going to be manufactured.

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Cement

Cement is an integral part of the urban infrastructure. Cement, one of the most important building materials, is a binding agent that sets and hardens to adhere to building units such as stones, bricks, tiles, etc. Cement generally refers to a very fine powdery substance chiefly made up of limestone (calcium), sand or clay (silicon), bauxite (aluminum), and iron ore, and may include shells, chalk, marl, shale, blast furnace slag, slate. The raw ingredients are processed in cement manufacturing plants and heated to form a rock-hard substance, which is then ground into a fine powder. Cement mixed with water causes a chemical reaction and forms a paste that sets and hardens to bind individual structures of building materials. Cement hardens both in the air and under water and remains in its hardened state once reached.

It is used to make concrete as well as mortar, and to secure the infrastructure by binding the building blocks. Concrete is made of cement, water, sand, and gravel mixed in definite proportions, whereas mortar consists of cement, water, and fine aggregate. These are both used to bind rocks, stones, bricks, and other building units, fill or seal any gaps, and make decorative patterns. Cement mixed with water silicates and aluminates makes a water-repellant hardened mass that is used for water-proofing.

Cements are classified according to their early and final strength as well as their composition. Depending on the desired application, different types of cement – each with a specific composition are necessary. Cement characteristics can also be modified through the use of additives.

History of Cement

Cement has been used in many forms since the advent of human civilization. From volcanic ashes, crushed pottery, burnt gypsum and hydrated lime to the first hydraulic cement used by the Romans in the middle ages, the development of cement continued to the 18th century, when James Parker patented Roman cement, which gained popularity but was replaced by Portland cement in the 1850s.

In the 19th century, Frenchman Louis Vicat laid the foundation for the chemical composition of Portland cement and in Russia, Egor Cheliev published the methods of making cement, uses of cement and advantages. Bricklayer Joseph Aspdin of Leeds, England first made portland cement early in the 19th century by burning powdered limestone and clay in his kitchen stove. With this crude method, he laid the foundation for an industry that annually processes literally mountains of limestone, clay, cement rock, and other materials into a powder so fine it will pass through a sieve capable of holding water. Joseph Aspdin brought Portland cement to the market in England and his son, William Aspdin, developed the modern Portland cement, which was soon in quite high demand.

In the 19th century, Rosendale cement was discovered in New York. Though its rigidity made it quite popular at first, the market demand soon declined because of its long curing time and Portland cement was again the favorite. However, a new blend of Rosendale-Portland cement, which is both highly durable and needs less curing time and is now often used for highway or bridge construction.

The cement used today has undergone experimentation, testing and significant improvements to meet the needs of the present world, such as developing strong concretes for roads and highways, hydraulic mortars that endure sea water, and stucco for wet climates. Different kinds of modern cements are Ordinary Portland cement (OPC), Portland Slag cement, Portland Pozzolana cement, White cement, Sulphate resisting cement, Low heat Portland cement, Rapid hardening cement, Quick setting cement, Blast Furnace Slag cement, High Alumina cement, Coloured cement, Air Entraining cement, Expansive cement, Hydrographic cement etc.

Cement Manufacturing Industries in the World

The top three cement producers in the world as recorded in 2010 are the USA, China and India. Among these countries, China alone manufactures about 45% of the total worldwide production of cement. Global consumption of cement continues to rise since it is a non-recyclable product and so every new construction or repair needs new cement. Especially in the economies of Asia and Eastern Europe, cement production is an important element of progress.

According to the global cement directory, there are about 2273 active cement production plants in the world. Some of the leading cement manufacturers are Lafarge Holcim, Anhui Conch, China National Building Materials, Heidelberg Cement, Cemex, Italcementi, China Resources Cement, Taiwan Cement, Eurocement and Votorantim. The total global consumption of cement, as indicated by statistics in 2015, measures up to 18 million metric tons, most of which is attributed to the rising national economy of North America.

Among the developed capitalist countries, the leading producers of cement are the USA, France, Italy and Germany. Iran, now the top producer in the Middle East, occupies the third position in the world for cement manufacture. Asian and African countries are also progressive in the production of cement.

The kiln process in cement plants causes the emission of carbon dioxide, which is one of the major greenhouse gases responsible for global warming. With a view to reducing, even eliminating, the harmful environmental impacts of cement usage, leading industries are now trying to implement technologies that utilize recycled materials and renewable energy sources. “Green cement” is such a sustainable construction material that is the result of extensive research related to the adverse effects of global warming.

Manufacturing of cement

Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients. Common materials used to manufacture cement include limestone, shells and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand and iron ore. These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder, i.e. cement.

The most common way to manufacture cement is through a dry method. Although the dry process is the most modern and popular way to manufacture cement, some kilns in the United States use a wet process. The two processes are essentially alike except in the wet process, the raw materials are ground with water before being fed into the kiln.

In dry process, the first step is to quarry the principal raw materials, mainly limestone, clay, and other materials. After quarrying the rock is crushed. This involves several stages. The first crushing reduces the rock to a maximum size of about 6 inches. The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller.

The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed and fed to a cement kiln. The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter and longer in many instances than the height of a 40-story building. The large kilns are mounted with the axis inclined slightly from the horizontal.

The finely ground raw material or the slurry is fed into the higher end. At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels or gas under forced draft. As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles.

Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers. The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency. After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone. The cement is now ready for transport to various construction sites.

Cement plant laboratories check each step in the manufacture of cement by frequent chemical and physical tests. The labs also analyze and test the finished product to ensure that it complies with all industry specifications.

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Civil Engineering Functions

The functions of the civil engineer can be divided into three categories: those performed before construction (feasibility studies, site investigations, and design), those performed during construction (dealing with clients, consulting engineers, and contractors) and those performed after construction (maintenance and research).

1) Feasibility studies

No major project today is started without an extensive study of the objective and without preliminary studies of possible plans leading to a recommended scheme, perhaps with alternatives. Feasibility studies may cover alternative methods.

2) Site investigations

A preliminary site investigation is part of the feasibility study, but once a plan has been adopted a more extensive investigation is usually imperative. Money spent in a rigorous study of ground and substructure may save large sums later in remedial works or in changes made necessary in constructional methods.

3) Design

The design of engineering works may require the application of design theory from many fields—e.g., hydraulics, thermodynamics, or nuclear physics. Research in structural analysis and the technology of materials has opened the way for more rational designs, new design concepts, and greater economy of materials. The theory of structures and the study of materials have advanced together as more and more refined stress analysis of structures. Modern designers not only have advanced theories and readily available design data, but structural designs can now be rigorously analyzed by computers.

4) Construction

The promotion of civil engineering works may be initiated by a private client, but most work is undertaken for large corporations, government authorities, public boards and authorities. Many of these have their own engineering staffs, but for large specialized projects it is usual to employ consulting engineers.

The consulting engineer may be required first to undertake feasibility studies, then to recommend a scheme and quote an approximate cost. The engineer is responsible for the design of the works, supplying specifications, drawings, and legal documents in sufficient detail to seek competitive tender prices. The engineer must compare quotations and recommend acceptance of one of them. Although not a party to the contract, the engineer’s duties are defined in it; the staff must supervise the construction and the engineer must certify completion of the work.

A phenomenon of recent years has been the turnkey or package contract, in which the contractor undertakes to finance, design, specify, construct, and commission a project in its entirety. In this case, the consulting engineer is engaged by the contractor rather than by the client.

5) Maintenance

The contractor maintains the works to the satisfaction of the consulting engineer. Responsibility for maintenance extends to ancillary and temporary works where these form part of the overall construction. After construction a period of maintenance is undertaken by the contractor, and the payment of the final installment of the contract price is held back until released by the consulting engineer. Central and local government engineering and public works departments are concerned primarily with maintenance, for which they employ direct labour.

6) Research

Research in the civil engineering field is undertaken by government agencies, industrial foundations, the universities and other institutions. Most countries have government-controlled agencies involved in a broad spectrum of research, and establishments in building research, roads and highways, hydraulic research, water pollution and other areas. Many are government-aided but depend partly on income from research work promoted by industry.

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Sub-disciplines/Branches in Civil Engineering

There are a number of sub-disciplines within the broad field of civil engineering. General civil engineers work closely with surveyors and specialized civil engineers to design grading, drainage, pavement, water supply, sewer service, dams, electric and communications supply. Civil engineers apply the principles of geotechnical engineering, structural engineering, environmental engineering, transportation engineering and construction engineering to residential, commercial, industrial and public works projects of all sizes and levels of construction.

1. Structural Engineering

Structural engineering is concerned with the structural design and structural analysis of buildings, bridges, towers, flyovers (overpasses), tunnels, off shore structures like oil and gas fields in the sea, aero structure and other structures. This involves identifying the loads which act upon a structure and the forces and stresses which arise within that structure due to those loads and then designing the structure to successfully support and resist those loads. The loads can be self weight of the structures, other dead load, live loads, moving (wheel) load, wind load, earthquake load, load from temperature change etc. The structural engineer must design structures to be safe for their users and to successfully fulfill the function.

Design considerations will include strength, stiffness, and stability of the structure when subjected to loads which may be static, such as furniture or self-weight, or dynamic, such as wind, seismic, crowd or vehicle loads or transitory, such as temporary construction loads or impact. Other considerations include cost, construction procedure, safety, aesthetics and sustainability.

2. Geotechnical Engineering

Geotechnical engineering studies rock and soil supporting civil engineering systems. Knowledge from the field of soil science, materials science, mechanics, and hydraulics is applied to safely and economically design foundations, retaining walls and other structures. Geotechnical engineering is the study of the behaviour of soils under the influence of loading forces and soil-water interactions. This knowledge is applied to the design of foundations, retaining walls, earth dams, clay liners and geosynthetics for waste containment.

The geotechnical engineer is involved in field and laboratory investigations to determine the engineering properties of site soils and other geomaterials and their subsequent use. Geotechnical engineering includes the analysis, design and construction of foundations, slopes, retaining structures, embankments, roadways, tunnels, levees, wharves, landfills and other systems that are made of or are supported by soil or rock.

3. Surveying

Surveying is the process by which a surveyor measures certain dimensions that occur on or near the surface of the earth. Surveying equipment such as levels and theodolites are used for accurate measurement of angular deviation, horizontal, vertical and slope distances. With computerization, electronic distance measurement (EDM), total stations, GPS surveying and laser scanning have to a large extent supplanted traditional instruments. Data collected by survey measurement is converted into a graphical representation of the earth's surface in the form of a map. Elements of a structure must be sized and positioned in relation to each other and to site boundaries and adjacent structures.

Although surveying is a distinct profession with separate qualifications and licensing arrangements, civil engineers are trained in the basics of surveying and mapping, as well as geographic information systems. Surveyors also lay out the routes of railways, tramway tracks, highways, roads, pipelines and streets as well as positioning other infrastructure, such as harbors, before construction.

4. Transportation Engineering

Transportation engineering is concerned with moving people and goods efficiently, safely, and in a manner conducive to a vibrant community. This involves specifying, designing, constructing and maintaining transportation infrastructure which includes streets, canals, highways, rail systems, airports, ports, and mass transit. It includes areas such as transportation design, transportation planning, traffic engineering, some aspects of urban engineering, pavement engineering, Intelligent Transportation System (ITS), and infrastructure management.

5. Environmental Engineering

Environmental engineering is the contemporary term for sanitary engineering, though sanitary engineering traditionally had not included much of the hazardous waste management and environmental remediation work covered by environmental engineering. Environmental engineering deals with treatment of chemical, biological or thermal wastes, purification of water and air and remediation of contaminated sites after waste disposal or accidental contamination.

6. Materials Science and Engineering

Materials science is closely related to civil engineering. It studies fundamental characteristics of engineering materials such as concrete, fine and coarse aggregates, cement, strong metals such as aluminum and steel and thermosetting polymers including polymethylmethacrylate (PMMA) and carbon fibers etc. Materials engineering involves protection and prevention (paints and finishes). Alloying combines two types of metals to produce another metal with desired properties.

7. Construction Engineering

Construction engineering involves planning and execution, transportation of materials, site development based on hydraulic, environmental, structural and geotechnical engineering. As construction firms tend to have higher business risk than other types of civil engineering firms, construction engineers often engage in more business-like transactions, for example, drafting and reviewing contracts, evaluating logistical operations, and monitoring prices of supplies.

6. Coastal Engineering

Coastal engineering is concerned with managing coastal areas. The objectives of this branch involve management of shoreline erosion, improvement of navigation channels and harbors, protection against flooding brought on by storms, tides and even seismically triggered waves (tsunamis), improvement of coastal recreation and management of pollution in nearby marine environments. Coastal engineering typically includes the development of structures, in addition to the transportation and probable stabilization of beach sand along with other coastal sediments.

7. Earthquake Engineering

Earthquake engineering involves designing structures to withstand hazardous earthquake exposures. Earthquake engineering is a sub-discipline of structural engineering. The main objectives of earthquake engineering are to understand interaction of structures on the shaky ground, foresee the consequences of possible earthquakes and design, construct and maintain structures to perform at earthquake in compliance with building codes.

8. Municipal Engineering

Municipal engineering is concerned with municipal infrastructure. This involves specifying, designing, constructing and maintaining streets, sidewalks, water supply networks, sewers, street lighting, municipal solid waste management and disposal, storage depots for various bulk materials. In the case of underground utility networks, it may also include the civil portion (conduits and access chambers) of the local distribution networks of electrical and telecommunications services. It can also include the optimizing of waste collection, potable water supply, treatment or pretreatment of waste water, site drainage etc.

9. Urban Engineering 

Urban engineers design, build and manage the infrastructure systems such as roads, bridges, water supply, waste management and transportation that are vital for urban areas to function efficiently. Urban engineers provide a physical definition of the urban habitat by planning, designing, building/constructing, operating, and maintaining the infrastructure including buildings and roads. This infrastructure, on the one hand, facilitates social and economic interactions within the urban habitat through ubiquitous transportation and communication systems. On the other hand, it also directly affects physical health and ecological balance within

the urban system through the provision of drinking water, air quality and waste treatment. Urban engineering focuses on designing and managing infrastructure systems in urban areas. As the world's population becomes increasingly urbanized, the role of urban engineers has become more critical in ensuring the smooth functioning of cities.

10. Water resources engineering

Water resources engineering is concerned with the collection and management of water (as a natural resource). As a discipline it therefore combines elements of hydrology, environmental science, meteorology, conservation and resource management. This area of civil engineering relates to the prediction and management of both the quality and the quantity of water in both underground (aquifers) and above ground (lakes, rivers, and streams) resources. Water resource engineers analyze and model very small to very large areas of the earth to predict the amount and content of water as it flows into, through or out of a facility.

11. Fluid Mechanics 

Fluid mechanics deals with the study of fluids (liquids and gases) in a state of rest or motion is an important subject of civil, mechanical and chemical engineering. Its various branches are fluid statics, fluid kinematics and fluid dynamics. Fluid mechanics is concerned with the response of fluids to forces exerted upon them. A substance that flows is called as fluid. All liquid and gaseous substances are considered to be fluids. Water, oil, and others are very important in our day-to-day life as they are used for various applications. For instance water is used for generation of electricity in hydroelectric power plants and thermal power plants, water is also used as the coolant in nuclear power plants, oil is used for the lubrication of automobiles etc.

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History of Civil Engineering

Because of the civil engineering is a broad profession, including several specialized sub-disciplines, its history is linked to knowledge of structures, materials science, geography, geology, soils, hydrology, environmental science, mechanics, project management, and other fields. Throughout ancient and medieval history most architectural design and construction was carried out by artisans, such as stonemasons and carpenters, rising to the role of master builder.

One of the earliest examples of a scientific approach to physical and mathematical problems applicable to civil engineering is the work of Archimedes in the 3^rd century BC, including Archimedes' principle, which underpins our understanding of buoyancy, and practical solutions such as Archimedes' screw. Brahmagupta, an Indian mathematician, used arithmetic in the 7^th century AD, based on Hindu-Arabic numerals, for excavation (volume) computations.

Pyramids in Egypt

Engineering has been an aspect of life since the beginnings of human existence. The earliest practice of civil engineering may have commenced between 4000 and 2000 BC in ancient Egypt, the Indus Valley civilization and Mesopotamia (ancient Iraq) when humans started to abandon a nomadic existence, creating a need for the construction of shelter. During this time, transportation became increasingly important leading to the development of the wheel and sailing.

Qanat water management system

The construction of pyramids in Egypt (2700–2500 BC) were some of the first instances of large structure constructions. Other ancient historic civil engineering constructions include the Qanat water management system (the oldest is older than 3000 years and longer than 71 kilometres, the Parthenon by Iktinos in Ancient Greece (447–438 BC), the Appian Way by Roman engineers (c. 312 BC), the Great Wall of China by General Meng T'ien under orders from Ch'in Emperor Shih Huang Ti (c. 220 BC) and the stupas constructed in ancient Sri Lanka like the Jetavanaramaya and the extensive irrigation works in Anuradhapura. The Romans developed civil structures throughout their empire, including especially aqueducts, insulae, harbours, bridges, dams and roads.

Chichen Itza was a large pre-Columbian city in Mexico built by the Maya people of the Post Classic. The northeast column temple also covers a channel that funnels all the rainwater from the complex some 40 metres (130 ft) away to a rejollada, a former cenote.

Chichen Itza

In the 18^th century, the term civil engineering was coined to incorporate all things civilian as opposed to military engineering. In 1747, the first institution for the teaching of civil engineering, the École Nationale des Ponts et Chaussées (National School of Bridges and Roads) was established in France; and more examples followed in other European countries, like Spain. The first self-proclaimed civil engineer was John Smeaton, who constructed the Eddystone Lighthouse. In 1771 Smeaton and some of his colleagues formed the Smeatonian Society of Civil Engineers, a group of leaders of the profession who met informally over dinner. Though there was evidence of some technical meetings, it was little more than a social society.

In 1818 the Institution of Civil Engineers was founded in London. The institution received a Royal charter in 1828, formally recognising civil engineering as a profession. The first private college to teach civil engineering in the United States was Norwich University, founded in 1819 by Captain Alden Partridge. The first degree in civil engineering in the United States was awarded by Rensselaer Polytechnic Institute in 1835. The first such degree to be awarded to a woman was granted by Cornell University to Nora Stanton Blatch in 1905.

In the UK during the early 19^th century, the division between civil engineering and military engineering (served by the Royal Military Academy, Woolwich), coupled with the demands of the Industrial Revolution, spawned new engineering education initiatives: the Class of Civil Engineering and Mining was founded at King's College London in 1838, mainly as a response to the growth of the railway system and the need for more qualified engineers, the private College for Civil Engineers in Putney was established in 1839, and the UK's first Chair of Engineering was established at the University of Glasgow in 1840.

The beginnings of civil engineering as a separate discipline may be seen in the foundation in France in 1716 of the Bridge and Highway Corps, out of which in 1747 grew the “École Nationale des Ponts et Chaussées” (National School of Bridges and Highways). Its teachers wrote books that became standard works on the mechanics of materials, machines and hydraulics. As design and calculation replaced rule of thumb and empirical formulas, and as expert knowledge was codified and formulated, the nonmilitary engineer moved to the front of the stage. Talented, if often self-taught, craftsmen, stonemasons, millwrights, toolmakers, and instrument makers became civil engineers. In Britain, James Brindley began as a millwright and became the foremost canal builder of the century; John Rennie was a millwright’s apprentice who eventually built the New London Bridge; Thomas Telford, a stonemason, became Britain’s leading road builder.

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