introduction to civil engineering lecture 4

Introduction to Civil

Engineering

Lecture 4

1

Out lines

Code of Ethics.

Names and Symbols for the SI Base Units.

Materials of Construction.

2

3Code of Ethics. (from the American Society of Civil Engineers.)

Fundamental Principles

Engineers uphold and advance the integrity, honor and dignity of the engineering

profession by:

1. Using their knowledge and skill for the enhancement of human welfare;

2. Being honest and impartial and serving with fidelity the public, their employers

and clients;

3. Striving to increase the competence and prestige of the engineering profession;

and

4. Supporting the professional and technical societies of their disciplines.

Fundamental Canons

1. Engineers shall hold paramount the safety, health and welfare of the public in the performance of their professional

duties.

2. Engineers shall perform services only in areas of their competence.

3. Engineers shall issue public statements only in an objective and truthful manner.

4. Engineers shall act in professional matters for each employer or client as faithful agents or trustees, and shall avoid

conflicts of interest.

5. Engineers shall build their professional reputation on the merit of their services and shall not compete unfairly with

others.

6. Engineers shall act in such a manner as to uphold and enhance the honor, integrity and dignity of the engineering

profession.

7. Engineers shall continue their professional development throughout their careers, and shall provide opportunities for

the professional development of those engineers under their supervision.

4

Code of Ethics.

5Names and Symbols; for the SI Base Units

Physical Quantity Name of SI Unit Symbol for SI Unit

Length Meter m

Mass Kilogram kg

Time Second s

Temperature Celsius oC

Kelvin K oC=K– 273

Fahrenheit FoC= (F - 32) x5/9

International System of Units

The International System of Units (SI) defines seven units of measure as a

basic set from which all other SI units can be derived. The SI base units and

their physical quantities are the meter for measurement of length, the

kilogram for mass, the second for time, the ampere for electric current, the

kelvin for temperature, the candela for luminous intensity, and the mole for

amount of substance.

6Names and Symbols for the Units

7Names and Symbols for the Units

Imperial units

The system of imperial units or the imperial system (also known as British

Imperial or Exchequer Standards of 1825) is the system of units first defined

in the British Weights and Measures Act of 1824, which was later refined and

reduced. The Imperial units replaced the Winchester Standards, which were

in effect from 1588 to 1825. The system came into official use across the

British Empire. By the late 20th century, most nations of the former empire

had officially adopted the metric system as their main system of

measurement, although some imperial units are still used in the United

Kingdom, Canada and other countries formerly part of the British Empire.

The imperial system developed from what were first known as English units,

as did the related system of United States customary units.

8Names and Symbols for the SI Base Units

10

Conversion Constants and Multipliers

Names and Symbols; for the SI Base Units

12

Conversion Factors

Metric to English

13

1. Steel.

2. Concrete.

3. Bituminous Materials.

4. Bricks and Blocks.

Materials of Construction

14

1. Steel.

The applications of metals in civil engineering

are many and varied, ranging from their use as

main structural materials to their use for

fastenings and bearing materials.

As main structural materials cast iron and

wrought iron have been superseded by rolled-

steel sections.

Materials of Construction

15Materials of Construction

Steel.

Steel is of major importance for its use in reinforced and pre-stressed concrete. On smaller scale, metals

are extensively used for fastenings, such as nails and screws and for decorative facings.

The properties of metals which make them unique among construction materials are

- High tensile strength

- Ability to be formed into plate, sections and wire.

- Weldability or ease of welding

Other properties

- high thermal conductivity.

- electrical conductance.

- metallic luster.


Steel.

Disadvantage

-need to be protected from corrosion by moist conditions and the atmosphere.

In service, steel frequently has to resist

- high tensile or compressive forces ( Stress).

- corrosion

- shock loading

- low and high temperatures

- constantly varying forces

- combination of several of the above


Steel.

Use of steel in civil engineering.

1. Structural steel

Selection of structural steel is determined by the following factors

-strength level required

-other properties required (ductility, toughness...) together with the strength

-local conditions as imposed by codes and specifications


Steel.

Grades

Grade40; tensile strength 40 ksi (240 MPa)


By increasing the carbon content to 0.22% max, the strength increases.

Typical applications of structural steel are in

-Bridges.

-High-rise buildings,

-Spectator stands,

-Galvanized electricity power supply pylons and

-Welded pipelines.


Steel.

2. Concrete Reinforcement

Concrete has low tensile and bending strengths and high compressive strength. Steel

reinforcement overcomes the deficiencies in the tensile and bending strengths.

The reinforcing steel must have adequate tensile properties and form a strong bond

with the concrete. Reinforcing steel is supplied as round ribbed (deformed) bars and

as woven or electrically welded mesh.


Steel.

Grades




Steel.

3. Other applications

- pre-stressing steels.

- suspension bridge cables.

- cladding steels.

- bolt steels.

- railway steels.

22End of Lecture 4

Next Lecture :Concrete , Blocks.

introduction to civil engineering lecture 4

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