Civil Engineering Functions
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).
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—e.g., bridge versus tunnel, in the case of a water crossing—or, once
the method is decided, the choice of route. Both economic and engineering
problems must be considered.
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.
Since
the load-bearing qualities and stability of the ground are such important
factors in any large-scale construction, it is surprising that a serious study
of soil mechanics did not develop until the mid-1930s. Karl von Terzaghi, the
chief founder of the science, gives the date of its birth as 1936, when the
First International Conference on Soil Mechanics and Foundation Engineering was
held at Harvard University and an international society was formed. Today there
are specialist societies and journals in many countries, and most universities
that have a civil engineering faculty have courses in soil mechanics.
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 and systematic testing has been
done. Modern designers not only have advanced theories and readily available
design data, but structural designs can now be rigorously analyzed by
computers.
Construction
The
promotion of civil engineering works may be initiated by a private client, but
most work is undertaken for large corporations, government authorities, and
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 he is 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. Actions must be consistent with duty to the client; the
professional organizations exercise disciplinary control over professional
conduct. The consulting engineer's senior representative on the site is the
resident engineer.
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.
The
contractor is usually an incorporated company, which secures the contract on
the basis of the consulting engineer's specification and general drawings. The
consulting engineer must agree to any variations introduced and must approve
the detailed drawings.
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.
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, such as the United States Bureau of Standards
and the National Physical Laboratory of Great Britain, 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.
Branches of civil engineering
In 1828 Thomas Tredgold of England
wrote:
The most important object of Civil
Engineering is to improve the means of production and of traffic in states,
both for external and internal trade. It is applied in the construction and
management of roads, bridges, railroads, aqueducts, canals, river navigation,
docks and storehouses, for the convenience of internal intercourse and
exchange; and in the construction of ports, harbours, moles, breakwaters and
lighthouses; and in the navigation by artificial power for the purposes of
commerce.
It is applied to the protection of property
where natural powers are the sources of injury, as by embankments for the
defence of tracts of country from the encroachments of the sea, or the
overflowing of rivers; it also directs the means of applying streams and rivers
to use, either as powers to work machines, or as supplies for the use of cities
and towns, or for irrigation; as well as the means of removing noxious
accumulations, as by the drainage of towns and districts to . . . secure the
public health.
A
modern description would include the production and distribution of energy, the
development of aircraft and airports, the construction of chemical process
plants and nuclear power stations, and water desalination. These aspects of
civil engineering may be considered under the following headings: construction,
transportation, maritime and hydraulic engineering, power, and public health.
Construction
Almost
all civil engineering contracts include some element of construction work. The
development of steel and concrete as building materials had the effect of
placing design more in the hands of the civil engineer than the architect. The
engineer's analysis of a building problem, based on function and economics,
determines the building's structural design.
Transportation
Roman
roads and bridges were products of military engineering, but the pavements of
McAdam and the bridges of Perronet were the work of the civil engineer. So were
the canals of the 18th century and the railways of the 19th, which, by providing
bulk transport with speed and economy, lent a powerful impetus to the
Industrial Revolution. The civil engineer today is concerned with an even
larger transportation field—e.g., traffic studies, design of systems for road,
rail, and air, and construction including pavements, embankments, bridges, and
tunnels.
Maritime and hydraulic engineering
Harbour
construction and shipbuilding are ancient arts. For many developing countries
today the establishment of a large, efficient harbour is an early imperative,
to serve as the inlet for industrial plant and needed raw materials and the
outlet for finished goods. In developed countries the expansion of world trade,
the use of larger ships, and the increase in total tonnage call for more rapid
and efficient handling. Deeper berths and alongside-handling equipment (for
example, for ore) and navigation improvements are the responsibility of the
civil engineer.
The
development of water supplies was a feature of the earliest civilizations, and
the demand for water continues to rise today. In developed countries the demand
is for industrial and domestic consumption, but in many parts of the
world—e.g., the Indus basin—vast schemes are under construction, mainly for
irrigation to help satisfy the food demand, and are often combined with
hydroelectric power generation to promote industrial development.
Dams
today are among the largest construction works, and design development is
promoted by bodies like the International Commission on Large Dams. The design
of large impounding dams in places with population centres close by requires
the utmost in safety engineering, with emphasis on soil mechanics and stress
analysis. Most governments exercise statutory control of engineers qualified to
design and inspect dams.
Power
Civil
engineers have always played an important part in mining for coal and metals;
the driving of tunnels is a task common to many branches of civil engineering.
In the 20th century the design and construction of power stations has advanced
with the rapid rise in demand for electric power, and nuclear power stations
have added a whole new field of design and construction, involving prestressed
concrete pressure vessels for the reactor.
The
exploitation of oil fields and the discoveries of natural gas in significant
quantities have initiated a radical change in gas production. Shipment in
liquid form from the Sahara and piping from the bed of the North Sea have been
among the novel developments.
Public health
Drainage
and liquid-waste disposal are closely associated with antipollution measures
and the re-use of water. The urban development of parts of water catchment
areas can alter the nature of runoff, and the training and regulation of rivers
produce changes in the pattern of events, resulting in floods and the need for
flood prevention and control.
Modern
civilization has created problems of solid-waste disposal, from the manufacture
of durable goods, such as automobiles and refrigerators, produced in large
numbers with a limited life, to the small package, previously disposable, now
often indestructible. The civil engineer plays an important role in the
preservation of the environment, principally through design of works to enhance
rather than to damage or pollute.
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