Hello,

I would like to show very first how to visualize the subject. For this, we should have total concentration. To avoid obstacle coming in front of us, we will follow the following steps.

Close your eyes, try to identify any Object.,Whatever it may be and ask the following questions yourself.

1. What is that object made from?
2. What are the properties that an object supposed to have to perform functional need?
3. Is that object has this property by birth, or it introduced by some mean? If yes, what are that processes?
4. How one can come to know the properties of any object? Available instruments for that.
5. What might be failure problems faced by that object, and what preventive measures we can do?

This is a reverse engineering way of learning and teaching,

Eg.

1. I imagine object_ Helmet.
2. It should be tough enough if impact occurs on it and at the same time smooth inside to protect the head from injury.
3. All those things not by birth and artificially added by material selection to selecting mfg, the process followed with Heat Treatment.
4. Confirmation properties by Impact Test, Hardness Test, etc.
5. It may corrode, get scratched, and wear tear, so the appropriate coating is necessary for the same.

These all things you will get from nothing from Material Science and Metallurgy subject. All that complicated things we have to step by in this subject.

I hope you will better understand the importance of this subject.

Bar Bending Schedule, commonly referred to as “BBS” is a comprehensive list that describes the location, mark, type, size, length and number, and bending details of each bar or fabric in a Reinforcement Drawing of a Structure. ... In context of Reinforcement bars, it is called bar scheduling.

Introduction

Very frequently, we need to calculate frictional pressure drops in pipelines. Many of us may have domestic pumps in our households. After we estimate the pump flow from expected consumption of water, we need to calculate the pump head for purchasing a suitable pump. The following is an example of calculation of pressure drop when the flow and pipe geomerty is known.

Input Data(assumed)

1. Pipe flow -10 m³/h

2. Fluid-Water at 25⁰C. 

3. Pipe material-commercial galvanised carbon steel (absolute roughness ε=0.15 mm)

4.. Flow geometry as below(total pipe length L=20 m).

h₁=3m

h₂=12m

Calculation

Step-1 Calculation of flow velocity

From pipe dimension table for 25mm NB std thickness pipe

OD (D)=33.4 mm

Thickness (t)=3.38 mm

Hence ID(d)=D-2t=33.4-2x3.38=26.64 mm=0.02664 m

Pipe flow area (A)=(π/4)d²= (π/4)x0.02664²=0.000557 m² 

Pipe flow (Q)=10 m³/h=10/3600=0.00278 m³/s

Hence pipe flow velocity(V)=Q/A=0.00278/0.000557=4.98 m/s

Step-2 Calculation of Darcy's Friction Factor(f)

Kinematic viscosity of water(ν)=8.92x10^-7 m²/s

Reynold's number (Re)=Vd/ν=4.98x0.02664/8.92x10^-7=1.9x10⁵

Re>2000 hence flow is turbulent

For determining f we use Moody's chart s below:

 ^{Relative roughness (ε/d)=0.15/1000/0.02664=0.005631}

^{We noe find f from Re and ε/d as follows}

^{Hence f=0.031}

 ^{Step 3 Calculation Pipe Friction Drop}

 Total pipe length L=20 m

Minor losses

Minor losses are calculated by K factors. Different K factors are available in the internet(refer Crane Technical Paper 410)

a) Inlet loss-K₁=1

b) Foot valve with strainer-pressure drop Δp_f1=0.1 bar(assumed)=1x10⁴ Pa

c) Elbows 90⁰ -3 Nos, K₂=3x30f=3x30x0.031=2.79

d) Gate valve -2 nos, K3=2x8f=2x8x0.031=0.496

e) Exit loss, K4=1

Total head drop

h_f= (fL/D+K₁+K₂+K₃+K₄)V²/2g+ Δp_f1/ρg (Note :ρ=density=1000 kg/m³)

=(0.031x20/0.02664+1+2.79+0.496+1)(4.98²/2x9.81)+1x10⁴/(1000x9.81)

=37.12 mwc

Step 4 Calculation of Pump Head

In addition to frictional head loss we have static head increase

Pump head (H)=(h₁+h₂)+h_f= 3+12+37.12

H=52.12 mwc

We normally take some margin (say 15 %)for future increase in pipe friction drop due to ageing and calculation uncertainties.

So

H=52.12x1,15=60 mwc

Pump details, 10 m³/h flow, 60 mwc head.

• Tied Column.
• Spiral Column.
• Composite column.
• Axially Loaded Column.
• Column with Uniaxial Eccentric Loading.
• Column with Biaxial Eccentric Loading.
• Short Column.

• In this method, ultimate or collapse load is used as design load.
• The ultimate loads are obtained by increasing the working/service loads suitably by some factors.
• These factors which are multiplied by the working loads to obtain ultimate loads are called as load factors

BASIC PRINCIPLES IN SURVEYING

PRINCIPLE OF WORKING FROM WHOLE TO PART

• It is a fundamental rule to always work from the whole to the part. This implies a precise control surveying as the first consideration followed by subsidiary detail surveying.
• This surveying principle involves laying down an overall system of stations whose positions are fixed to a fairly high degree of accuracy as control, and then the survey of details between the control points may be added on the frame by less elaborate methods. 

• Once the overall size has been determined, the smaller areas can be surveyed in the knowledge that they must (and will if care is taken) put into the confines of the main overall frame. 

• Errors which may inevitably arise are then contained within the framework of the control points and can be adjusted to it.

Surveying is based on simple fundamental principles which should be taken into consideration to enable one get good results: 

(a) Working from the whole to the part is achieved by covering the area to be surveyed with a number of spaced out control point called primary control points called primary control points whose pointing have been determined with a high level of precision using sophisticated equipments. Based on these points as theoretic, a number of large triangles are drawn. Secondary control points are then established to fill the gaps with lesser precision than the primary control points. At a more detailed and less precise level, tertiary control points at closer intervals are finally established to fill in the smaller gaps. The main purpose of surveying from the whole to the part is to localize the errors as working the other way round would magnify the errors and introduce distortions in the survey. In partial terms, this  principle involve covering the area to be surveyed with large triangles. These are further divided into smaller triangles and the process continues until the area has been sufficiently covered with small triangles to a level that allows detailed surveys to be made in a local level. Error is in the whole operation as the vertices of the large triangles are fixed using higher precision instruments.

(b) Using measurements from two control parts to fix other points. Given two points whose length and bearings have been accurately determined, a line can be drawn to join them hence surveying has control reference points. The locations of various other points and the lines joining them can be fixed by measurements made from these two points and the lines joining them.

IMPORTANCE OF SCIENTIFIC HONESTY 

• Honesty is essential in booking notes in the field and when plotting and computations in the office. There is nothing to be gained from cooking the survey or altering dimensions so that points will tie-in on the drawing. It is utterly unprofessional to betray such trust at each stage of the survey.
• This applies to the assistants equally as it does to the surveyor in charge. Assistants must also listen carefully to all instructions and carry them out to the later without questions.

CHECK ON MEASUREMENTS

• The second principle is that; all survey work must be checked in such a way that an error will be apparent before the survey is completed.
• Concentration and care are necessary in order to ensure that all necessary measures are taken to the required standard of accuracy and that nothing is omitted. Hence they must be maintained in the field at all times. 

• Surveyor on site should be checking the correctness of his own work and that of others which is based on his information.
• Check should be constantly arranged on all measurements wherever possible. Check measurements should be conducted to supplement errors on field. Pegs can be moved, sight rails altered etc. 

• Survey records and computations such as field notes, level books, field books, setting out record books etc must be kept clean and complete with clear notes and diagrams so that the survey data can be clearly understood by others. Untidy and anonymous figures in the field books should be avoided. 

• Like field work, computations should be carefully planned and carried out in a systemic manner and all field data should be properly prepared before calculations start. Where possible, standardized tables and forms should be used to simplify calculations. If the result of a computation has not been checked, it is considered unreliable and for this reason, frequent checks should be applied to every calculation procedure. 

• As a check, the distances between stations are measured as they are plotted, to see that there is correspondence with the measured horizontal distance. Failure to match indicates an error in plotting or during the survey. 

• If checks are not done on observations, expensive mistake may occur. It is always preferable to take a few more dimensions on site to ensure that the survey will resolve itself at the plotting stage

 ACCURACY AND PRECISION

These terms are used frequently in engineering surveying both by manufacturers when quoting specifications for their equipments and on site by surveyors to describe results obtained from field work.

• Accuracy allows a certain amount of tolerance (either plus or minus) in a measurement, while; 

• Precision demands exact measurement. Since there is no such things as an absolutely exact measurement, a set of observations that are closely grouped together having small deviations from the sample mean will have a small standard error and are said to be precise.

Horizontal Distance Measurement

One of the basic measurements in surveying is the determination of the distance between two points on the earth’s surface for use in fixing position, set out and in scaling. Usually spatial distance is measured. In plane surveying, the distances measured are reduced to their equivalent horizontal distance either by the procedures used to make the measurement or by applying numerical corrections for the slope distance (spatial distance). The method to be employed in measuring distance depends on the required accuracy of the measurement, and this in turn depends on purpose for which the measurement is intended

Pacing: where approximate results are satisfactory, distance can be obtained by pacing (the number of paces can be counted by tally or pedometer registry attached to one leg). Average pace length has to be known by pacing a known distance several times and taking the average. It is used in reconnaissance surveys& in small scale mapping.

Odometer of a vehicle: Based on diameter of tires (no of revolutions X wheel diameter); this method gives a fairly reliable result provided a check is done periodically on a known length. During each measurement a constant tyre pressure has to be maintained.

Tachometry: -Distance can be can be measured indirectly by optical surveying instruments like theodolite. The method is quite rapid and sufficiently accurate for many types of surveying operations.

Taping (chaining): - This method involves direct measurement of distances with a tape or chain. Steel tapes are most commonly used .It is available in lengths varying from 15m to 100m. Formerly on surveys of ordinary precision, lengths of lines were measured with chains.

Electronic Distance Measurement (EDM): - are indirect distance measuring instruments that work using the invariant velocity of light or electromagnetic waves in vacuum. They have high degree of accuracy and are effectively used for long distances for modern surveying operations.