Monday, 5 December 2016

What are the Roles and Responsibilities of a Civil Engineer?

What are the Roles and Responsibilities of a Civil Engineer?
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What is a civil engineer do?
Civil engineers design, build, supervise, operate, and maintain construction projects and systems in the public and private sector, including roads, buildings, airports, tunnels, dams, bridges, and systems for water supply and sewage treatment. Many civil engineers work in design, construction, research, and education.
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Civil Engineering incorporates a broad range of different job roles. From the construction of highways and buildings to dams, tunnels, bridges and other smaller facilities the role and responsibility of civil engineers is vast.
The two crucial aspects within this field are consulting engineering and contracting engineering. Consulting engineers design a specific project whereas contracting engineers manage the physical construction and play a significant role in transforming the proposed development into architecture.
Civil engineering further encompasses a number of other specialisations, each of which is essential for successful completion of the structure. The key roles and responsibilities of the civil engineer are as listed below.
The first, and most important, responsibility is to analyse the site location and the surrounding area. This includes a search and investigation, verifying its feasibility for construction purposes.
The second is to design a plan, outlining the key variables and what needs to be changed prior to the construction.
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The third role and responsibility of civil engineer is to develop a detailed design layout, keeping the requirements of the client in mind. The design and any subsequent reports need to be reviewed and approved, and any potential risks and challenges of the project identified.
Following the completion of this tender the proposal will need to be submitted to those officials that supervise the tendering process, ensuring that all rules, regulations and guidelines are fulfilled. It’s paramount that all safety measures are met whilst the project is being undertaken.
Whilst the project is underway it is the responsibility of the civil engineer to monitor the staff onsite. They must keep an open dialogue with architects, consultants and subcontractors. Should any issues arise, they have the responsibility of resolving them.
Wherever possible all construction work should be completed within budget and to the agreed timescale. The responsibility of scheduling the work, ensuring that sound organisational skills are employed and that all the raw materials are present also lies with a civil engineer.
A civil engineer plays a pivotal role in the effective execution of all manner of engineering projects. Their input, and leadership where necessary is essential to secure the smooth execution of a vast selection of projects.

History of Civil Engineering

History of Civil Engineering:

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It is difficult to determine the history of emergence and beginning of civil engineering, however, that the history of civil engineering is a mirror of the history of human beings on this earth. Man used the old shelter caves to protect themselves of weather and harsh environment, and used a tree trunk to cross the river, which being the demonstration of ancient age civil engineering.
Civil Engineering has been an aspect of life since the beginnings of human existence. The earliest practices of Civil engg may have commenced between 4000 and 2000 BC in Ancient Egypt and Mesopotamia (Ancient Iraq) when humans started to abandon a nomadic existence, thus causing a need for the construction of shelter. During this time, transportation became increasingly important leading to the development of the wheel and sailing.
Until modern times there was no clear distinction between civil engg and architecture, and the term engineer and architect were mainly geographical variations referring to the same person, often used interchangeably. The construction of Pyramids in Egypt (circa 2700-2500 BC) might be considered the first instances of large structure constructions.
Around 2550 BC, Imhotep, the first documented engineer, built a famous stepped pyramid for King Djoser located at Saqqara Necropolis. With simple tools and mathematics he created a monument that stands to this day. His greatest contribution to engineering was his discovery of the art of building with shaped stones. Those who followed him carried engineering to remarkable heights using skill and imagination.
Ancient historic civil engineering constructions include the Qanat water management system (the oldest older than 3000 years and longer than 71 km,) 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.
Other remarkable historical structures are Sennacherib's Aqueduct at Jerwan built in 691 BC; Li Ping's irrigation projects in China (around 220 BC); Julius Caesar's Bridge over the Rhine River built in 55 BC, numerous bridges built by other Romans in and around Rome(e.g. the pons Fabricius); Pont du Gard (Roman Aqueduct, Nimes, France) built in 19 BC; the extensive system of highways the Romans built to facilitate trading and (more importantly) fast manoeuvring of legions; extensive irrigation system constructed by the Hohokam Indians, Salt River, AZ around 600 AD; first dykes defending against high water in Friesland, The Netherlands around 1000 AD; El Camino Real - The Royal Road, Eastern Branch, TX and Western Branch, NM (1500s AD).
Machu Picchu, Peru, built at around 1450, at the height of the Inca Empire is considered an engineering marvel. It was built in the Andes Mountains assisted by some of history’s most ingenious water resource engineers. The people of Machu Picchu built a mountain top city with running water, drainage systems, food production and stone structures so advanced that they endured for over 500years.
A treatise on Architecture, Book called Vitruvius' De Archiectura, was published at 1AD in Rome and survived to give us a look at engineering education in ancient times. It was probably written around 15 BC by the Roman architect Vitruvius and dedicated to his patron, the emperor Caesar Augustus, as a guide for building projects.
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. Knowledge was retained in guilds and seldom supplanted by advances. Structures, roads and infrastructure that existed were repetitive, and increases in scale were incremental.
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 3rd 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 7th century AD, based on Hindu-Arabic numerals, for excavation (volume) computations.

Educational & Institutional history of civil engineering

In the 18th century, the term civil engineering was coined to incorporate all things civilian as opposed to military engineering. The first engineering school, The National School of Bridges and Highways, France, was opened in 1747. 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, world’s first engineering society, the Institution of Civil Engineers was founded in London, and in 1820 the eminent engineer Thomas Telford became its first president. The institution received a Royal Charter in 1828, formally recognizing civil engineering as a profession. Its charter defined civil engineering as: “Civil engineering is the application of physical and scientific principles, and its history is intricately linked to advances in understanding of physics and mathematics throughout history. Because civil engineering is a wide ranging profession, including several separate specialized sub-disciplines, its history is linked to knowledge of structures, material science, geography, geology, soil, hydrology, environment, mechanics and other fields.”

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.

Thursday, 1 December 2016

LESSON NOTE ON DEFINITIONS OF TERMS IN SURVEY

DEFINITIONS OF TERMS
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levelling is the term applied to any method of measuring directly with a graduated staff the difference in elevation between two or more points.
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Precise levelling is a particularly accurate method of differential levelling which uses highly accurate levels and with a more rigorous observing procedure than general engineering levelling. It aims to achieve high orders of accuracy such as 1 mm per 1 km traverse.

A level surface is a surface which is everywhere perpendicular to the direction of the force of gravity. An example is the surface of a completely still lake. For ordinary levelling, level surfaces at different elevations can be considered to be parallel.
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A level datum is an arbitrary level surface to which elevations are referred. The most common surveying datum is mean sea-level (MSL), but as hydrological work is usually just concerned with levels in a local area, we often use:

An assumed datum, which is established by giving a benchmark an assumed value (e.g. 100.000 m) to which all levels in the local area will be reduced. It is not good practice to assume a level which is close to the actual MSL value, as it creates potential for confusion.

A reduced level is the vertical distance between a survey point and the adopted level datum.

A bench mark (BM) is the term given to a definite, permanent accessible point of known height above a datum to which the height of other points can be referred.

It is usually a stainless steel pin embedded in a substantial concrete block cast into the ground. At hydrological stations rock bolts driven into bedrock or concrete structures can be used, but structures should be used warily as they themselves are subject to settlement. The locations of benchmarks shall be marked with BM marker posts and/or paint, and recorded on the Station History Form.

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A set-up refers the position of a level or other instrument at the time in which a number of observations are made without mooring the instrument. The first observation is made to the known point and is termed a backsight; the last observation is to the final point or the next to be measured on the run, and all other points are intermediates.

A run is the levelling between two or more points measured in one direction only. The outward run is from known to unknown points and the return run is the check levelling in the opposite direction.

A close is the difference between the starting level of the initial point for the outward run and that determined at the end of the return run. If the levels have been reduced correctly this value should be the same as the difference between the sum of the rises and falls and also the difference between the sum of the backsights and foresights.
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Height of Collimation is the elevation of the optical axis of the telescope at the time of the setup. The line of collimation is the imaginary line at the elevation.

Orders of levelling refer to the quality of the levelling, usually being defined by the expected maximum closing error. These are given in Table 1

 Order                   Purpose                                              Maximum close (m)
Precision order      Deformation surveys                        0.001 x km 
First order              Major levelling control                    0.003 x km
Second order          Minor levelling control                   0.007 x km
Third order            Levelling for construction                0.012 x km 
Table 1 Levelling 
The accuracy requirements for water-level stations relate to the standards; for further information refer to section 1.

Change points are points of measurement which are used to carry the measurements forward in a run. Each one will be read first as a foresight, the instrument position is changed, and then it will be read as a backsight. 


Lesson Note On Carrying out a level traverse






Carrying out a level traverse
To determine the difference in level between points on the surface of the ground a 'series' of levels will need to be carried out; this is called a level traverse or level run.
There are two method of levelling:
  1. Rise & Fall method and
  2. Height of collimation (height of instrument) methods
Click the link to see the animated rise&fall methods then click next for the height of collimation method. Please note when the shifting of the staff or level can be done using the rise&fall method
Leveling or Field Procedures
The leveling or field procedure that should be followed is shown in Figure 1 below..
http://www.boeingconsult.com/tafe/ss&so/survey1/level/levelling.GIF
Figure 1
  1. Set up the leveling instrument at Level position 1.
  2. Hold the staff on the Datum (RL+50 m) and take a reading. This will be a backsight, because it is the first staff reading after the leveling instrument has been set up.
  3. Move the staff to A and take a reading. This will be an intermediate sight.
  4. Move the staff to B and take a reading. This also will be an intermediate sight.
  5. Move the staff to C and take a reading. This will be another intermediate sight.
  6. Move the staff to D and take a reading. This will be a foresight; because after this reading the level will be moved. (A changeplate should be placed on the ground to maintain the same level.)
  7. The distance between the stations should be measured and recorded in the field book (see Table 1)
  8. Set up the level at Level position 2 and leave the staff at D on the changeplate. Turn the staff so that it faces the level and take a reading. This will be a backsight.
  9. Move the staff to E and take a reading. This will be an intermediate sight.
  10. Move the staff to F and take a reading. This will be a foresight; because after taking this reading the level will be moved.
  11. Now move the level to Leveling position 3 and leave the staff at F on the changeplate.
Now repeat the steps describe 8 to 10 until you finished at point J.
Field procedures for leveling
All staff readings should be recorded in the field book. To eliminate errors resulting from any line of sight (or collimation) backsights and foresights should be equal in distance. Length of sight should be kept less than 100 metres. Always commence and finish a level run on a known datum or benchmark and close the level traverse; this enables the level run to be checked.

There are two main methods of booking levels:
  • rise and fall method
  • height of collimation method
Table 1   Rise & Fall Method
Back-
sight
Inter-
mediate
Fore-
sight
Rise
Fall
Reduced
level
Distance
Remarks
2.554




50.00
0
Datum RL+50 m

1.783

0.771

50.771
14.990
A

0.926

0.857

51.628
29.105
B

1.963


1.037
50591
48.490
C
1.305

3.587

1.624
48.967
63.540
D / change point 1

1.432


0.127
48.840
87.665
E
3.250

0.573
0.859

49.699
102.050
F / change point 2

1.925

1.325

51.024
113.285
G
3.015

0.496
1.429

52.453
128.345
H / change point 3


0.780
2.235

54.688
150.460
J
10.124

5.436
7.476
2.788
54.688

Sum of B-sight & F-sight,
Sum of Rise & Fall
-5.436


-2.788

-50.000

Take smaller from greater
4.688


4.688

  4.688

Difference should be equal
The millimeter reading may be taken by estimation to an accuracy of 0.005 metres or even less.
  1. Backsight, intermediate sight and forsight readings are entered in the appropriate columns on different lines. However, as shown in the table above backsights and foresights are place on the same line if you change the level instrument.
  2. The first reduced level is the height of the datum, benchmark or R.L.
  3. If an intermediate sight or foresight is smaller than the immediately preceding staff reading then the difference between the two readings is place in the rise column.
  4. If an intermediate sight or foresight is larger than the immediately preceding staff reading then the difference between the two readings is place in the fall column.
  5. A rise is added to the preceding reduced level (RL) and a fall is subtracted from the preceding RL

While all arithmetic calculations can be checked there is no assurance that errors in the field procedure will be picked up. The arithmetic check proves only that the rise and fall is correctly recorded in the appropriate rise & fall columns. To check the field procedure for errors the level traverse must be closed. It is prudent to let another student check your reading to avoid a repetition of the level run.
If the arithmetic calculation are correct, the the difference between the sum of the backsights and the sum of the foresights will equal:
  • the difference between the sum of the rises and the sum of the falls, and

  • the difference between the first and the final R.L. or vice versa.
    (there are no arithmetic checks made on the intermediate sight calculations. Make sure you read them carefully)

Back-
sight
Inter-
mediate
Fore-
sight
Height of
collimation
Reduced
level
Distance
Remarks
2.554


52.554
50.00
0
Datum RL+50 m

1.783


50.771
14.990
A

0.926


51.628
29.105
B

1.963


50591
48.490
C
1.305

3.587
50.272
48.967
63.540
D / change point 1

1.432


48.840
87.665
E
3.250

0.573
52.949
49.699
102.050
F / change point 2

1.925


51.024
113.285
G
3.015

0.496
55.468
52.453
128.345
H / change point 3


0.780

54.688
150.460
J
10.124

5.436

54.688

Sum of B-sight & F-sight,
Difference between RL's
-5.436



-50.000

Take smaller from greater
4.688



  4.688

Difference should be equal
  1. Booking is the same as the rise and fall method for back-, intermediate- and foresights. There are no rise or fall columns, but instead a height of collimation column.
  2. The first backsight reading (staff on datum, benchmark or RL) is added to the first RL giving the height of collimation.
  3. The next staff reading is entered in the appropriate column but on a new line. The RL for the station is found by subtracting the staff reading from the height of collimation
  4. The height of collimation changes only when the level is moved to a new position. The new height of collimation is found by adding the backsight to the RL at the change point.
  5. Please note there is no check on the accuracy of intermediate RL's and errors could go undetected.
The rise and fall method may take a bit longer to complete, but a check on entries in all columns is carried out. The RL's are easier to calculate with the height of collimation method, but errors of intermediate RL's can go undetected. For this reason students should use the rise and fall method for all leveling exercises.

Always commence and finish a level run on a datum, benchmark or known RL. This is what is known as a closed level traverse, and will enable you to check the level run.
http://www.boeingconsult.com/tafe/ss&so/survey1/level/o&c-traverse.gif







Closed level traverse
Series of level runs from a known Datum or RL to a known Datum or RL.
Misclosure in millimeter
http://www.boeingconsult.com/tafe/ss&so/survey1/level/leq.gif  24 x √km
Closed loop level traverse
Series of level runs from a known Datum or RL back to the known Datum or RL.
Misclosure in millimeter
http://www.boeingconsult.com/tafe/ss&so/survey1/level/leq.gif  24 x √km






Open level traverse
Series of level runs from a known Datum or RL. This must be avoided because there are no checks on misreading