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Thursday, 15 June 2017

Design Of Steel Structures with Russian Standards

Their are basically 5 steps of design in  Russian system

1) Development of Design scheme.
2) Determination of Loads.
3) Calculation of Internal forces in Elements.
4) Selection of Cross Section.
5) Check for Designed Cross Section.


Loads & Loads Combination

INDIAN CODES :-

•) In India the Calculation of Dead load, Live Load & Wind load are done with reference of IS 875.

•) The Specialized Information of Industrial Buildings is provided by some codes like
IS 807.

•) For  Design of Earthquake Loads in India the reference of IS 1893 is taken into consideration.

•) For Design of  Towers & Other Forms of Structure the codes taken into consideration are IS 802, IS 9178, IS 6533.


RUSSIAN CODES :-

The Basic data on all types of loads except the earthquake loads are given in SP20.13300.2011 loads and effects code.

For Design of Earthquake loads or Sesmic Loads SP14.13330.2011 is taken into consideration.


Weight of Some Building Materials as per Russian Standards.



Loads & Effects

In Russian Standards all the loads are divided in two groups depending upon its duration and action.

1) Dead Load (Permanent): It includes the weight of Structures, Weight of Soil & pressure for underground soils, forces from prestress.

2) Live Load (Temporary): These loads are further divided into two sub category

2.a) Long Time loads like Store goods, machines in industrial Buildings, Pressure of Fluids Etc.

2.b) Short Time loads like Weight of People, Weight of Snow & Wind loads.

There is one special category designed for Earthquake loads and loads caused due to sudden breaches of technological process.


The load has two values-
a) Unfactored Load &
b) Design Load.


Unfactored Load ie Specified Characteristic Load are the loads that acts on structure during its operation.

Design Loads are the maximum possible loads that can act on structure.


Formula-     P = P^n  × (gamma)f

Where P.     = Design Load
         P^n.    = Unfactored Load
(gamma)f = Partial Safety Factor for loads
                        given in SP 20.13330.2011

(gamma)f = 1.05 For weight of steel.
(gamma)f = 1.04 For weight of  Snow.


The reability coefficient for load shows how many times the design load may exceed Unfactored load.


Sunday, 7 May 2017

VISIT EXPERIENCE AT WATER TREATMENT PLANT.

To become a Civil Engineer its very important to have a balance Theoretical Knowledge as well as Pratical Knowledge. Eventually with the same concept our visit was organised to WATER TREATMENT PLANT at Nigdi.

The visit was plan with the intention to enhance our theoretical knowledge with pratical experience.

The Water Treatment Plant is operated by Pimpri-Chinchwad Muncipal Corporation  (PCMC). Water is treated here and then supplied to the entire twin city.

The Water Treatment Plant works with basic aim to make water more acceptable for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, including being safely returned to the environment.


Water treatment plant Procedure


The Operation Cycle of Water Treatment Plant.

The Water Treatment Plant  work is distributed in 6 parts.

1) Intake source management to get fullfill amount of water every day.

2) Sampling Unit.

3) Processing Unit.

4) Storage unit.

5) Supervision & Control Unit.

6) Maintenance Unit.


Pavana Dam

The Intake Source


The intake source of Water Treatment Plant plays a very important role as the intake source should be sufficient to provide every day water requirement of Plant so as to avoid shortage of water.

The Intake Source of Water treatment Plant Nigadi is Pawna dam situated nearly 4km away from the plant. The plant treats 420 MLD ( ie Milions Litres Per Day).

PCMC is planning to build fourth water treatment plant in Chikhali.The new plant will enable the PCMC to treat water that will be drawn in future from Andra and Bhama Askhed dams to meet the growing needs of Pimpri Chinchwad.

The city's population is expected to rise to 25 lakh by 2025, which means the water supplied through Pavana dam will prove inadequate. As per the plan, the areas in Pavana and Mula river basins will get water drawn from Pavana dam while the areas in the Indrayani river basin will get water from Bhama Askhed and Andra dams, located around 20 kms away. From reports for Pimpri Chinchwad, the state government has sanctioned 167 MLD water from Bhama Askhed and 100 MLD water from Andra dam.


Laboratory Tests in WTP LAB

Laboratory Treatments

The water sample from source is been treated to examine the amount of contaminents and the selection of the suitable procedure of treatment.

The is managed by Mr. Sanket Mote and he guided us with the procedure conducted at the plant.

The test conducted are:
•)Turbidity
•)pH
•)Hardness
•)Heavy metals concentration


Equipments in Lab

Turbidity test is conducted to determine the amount of mud silt and other contaminents in water which cant be seen through naked eyes.

Turbidity is generally high in Rainy season as compared to other season therefore extra efforts are taken at the time of Rainy season.

Turbidity can be measured using either by an electronic turbidity meter or a turbidity tube. Turbidity is usually measured in Nephelometric turbidity units (NTU) or Jackson turbidity units (JTLJ),
depending on the method used for measurement. The two units are roughly equal.At Water treatment Plant the Turbidity is measured by Turbidity Meter
HACK2100QT.

Drinking water should have a turbidity of 5 NTU/JTU or less. Turbidity of more than 5 NTU/JTU would be noticed by users and may cause rejection of the supply.Where water is chlorinated, turbidity should be less than 5 NTU/JTU and preferably less than 1 NTU/JTU for chlorination to be effective

The dosage for alum to form coagulant is determined and added after aeration to for proper sedimentation. However if the amount of ciagulant is more then it affects the filteration process.


Bacterial Test

The bacterial test is conducted to determine the Pathogenic bacterias present in the sample.

There are some types of bacterial test like

1. MPN method.
2. Radicals.
3. Single path method.

The Equipment used to conduct Bacterial test at Water treatment Plant Nigdi was Single path kit for the 3rd method.

The aim of conducting the bacterial tests  determine the Pathogenic bacterias present in the sample so as to determine the amount of Chlorine dosage for bacterial degradation of water is designed.


Residual Chlorine Test.


The Residual Chlorine test is to determine the quantity of residual chlorine in the sample to preserve the quality  of  water supplied


Orthotolidine Test

In this test, 10 ml of chlorinated sample of water is taken after the required contact period, in a glass tube. To this 0.1 ml of orthotolidine solution is added. The color formed is observed after 5 minutes. The formation of yellow color normally indicates the presence of chlorine (either combined or free) in the water. The more yellow the color, the greater, is the chlorine residual. The amount of residual chlorine can be ascertained by comparing the colour developed in the glass tube with the standard colors already kept in the laboratory. This test, is therefore, very simple and does not require much technique or time. Under normal conditions, a lemon yellow color is satisfactory for public water supply. The orthotolidine test will normally gives the total residual chlorine present in water. However, it may be adjusted so as to give separately the quantities of free residual as well as combined residual of chlorine.

The free residual chlorine forms the yellow color during the first 5 seconds of the addition of orthotolidine, while the combined residual chlorine goes on forming the colour for about 5 minutes. Hence, the colour after 5 seconds will give the quantity of free residual chlorine, and the colour after 5 minutes will give the free and combined chlorine. The difference in value between the two values is the combined chlorine.

The orthotolidine test, however, is not accurate, because the impurities such as iron, manganese, nitrate etc., are likely to cause a false yellow colour, and indicating wrong and increased chlorine residual.


Cascaded Areator

Aeriation unit

This  is  the  starting  unit  of  the  water  treatment procedure. Once  the  sample  is  tested  the  water  coming from  Ravet  is  pumped  through  this  cascaded  aerator.  The purpose  of  having  an  aerator  is  to  improve  the  amount  of dissolved  oxygen  in  the  water  and  to  release  the  other gases,  also  a  few  metals  get  oxidized  during  this  procedure.

This  procedure  is  important  to  make the  water  odourless  as there  is  transmission  of  gases  during  this  process. Water is allowed to freely  fall  on the  cascaded steps and  which  each  fall  the  water  particles  are  exposed  to  the fresh  air  from  the  surrounding.  This  process  promotes  the exchange  of  gases  like  CO2,  etc. 

 


Clariflocculator

This is the second unit placed after Aeration unit.

flocculation  is  the  central  portion  of  the  tank  which  consist  of  a  mixer  that  is rotating  at  a  low  speed  to  facilitate  the  collision  of  the  charged  particles  and  their  conversion into  sludge which are  settled  down.

The water contains negatively charged particles whose amount is been analysed and the same quantity of positive bcharged particles are supplied in so as the positive charged particles and negative charged particles gets attracted to each other and as the size of this particles increases they settled down in Sedementation zone.

Sedimentation zone is the outer zone which is curved in nature and there is depression at the centre.

The  water  is  having  a  detention  time  of  0.5hr  in  the  flocculation  and  3hr  in  the sedimentation  zone.


Chlorination Unit

Chlorine is used to destroy disease-causing organisms in water, an essential step in delivering safe drinking water and protecting public health. Chlorine is by far the most commonly used disinfectant
in all regions of the world. Where widely adopted, chlorine has helped to virtually eliminate water- borne diseases such as cholera, typhoid and dysentery. Chlorine also eliminates slime bacteria, molds
and algae that commonly grow in water supply reservoirs, on the walls of water mains and in storage tanks. Only chlorine-based disinfectants leave a beneficial “residual” level that remains in treated
water, helping to protect it during distribution and storage. Chlorine is a versatile and low-cost disinfectant appropriate for any size water system, whether it serves a remote rural village or a large modern city. Where piped water supplies are not available, chlorine can also be used for treating water in individual households. Specially-packaged chlorine
bleach can disinfect household water.



However there are other disinfectants too like UV, Ozone, Boiling, Potassium Permaganet. But the main objective of adding disinfectant to water is to provide safe drinking water till it reach large span consumers. Therefore chlorine is the best option which satisfy all the requirements.



Storage  unit  and  pumping

In  this  unit  the  treated  water  is  allowed  to  stay  for  sometime  and  them  pumped  to the  distribution  network  by  using  mechanically  operated  pumps.  The  plant  is powered  by  electricity  from  the  MSEDCL


Filtration unit

This  is  a  big  unit  comprising  of  a  number  of  filter  pits.  The  filter  used  in  this  tank  was rapid  sand  filter  in  which  the  water  is  allowed  to  pass  through  the  sand  and  it  gets  filtered  as it  passes  down  under  the  action  of  gravity.  The  sand  is  having  small  pores  which  allows  water to  pass  through  it  preventing  the  suspended  matter.

During filtration the water enters the filter through upper valve, moves down towards thefilter bed, flows through the filter bed, passes the underdrainage system (filter bottom)and flows out through lower valve. The unit used to measure filtration rate is actually theapproach velocity, which is the inflow rate (m^3/h) divided by the filtration area (m^2).

When, after a period of operation, the filter rate controller is fully opened, further
clogging of the filter bed cannot be further compensated and the filtration rate will fall.
The filter is then taken out of service for backwashing.

For this, the upper and lower valves closed, and upper back wash valve  is opened to drain the remaining raw water out of the filter. A few minutes later lower backwash valve  is opened to admit the wash water.

The backwash rate should be high enough to expand the filter bed by about 20% so that the filter grains can be scoured, and the accumulated deposits carried away with the wash water. The wash water is collected in the wash water troughs from where it drains to waste. When the backwashing is completed, backwash valves  are closed and upper valve  is re-opened, admitting raw water to begin a new filter run.


Use  of  Supervisory  Control  and  Data  acquisition (SCADA)


This  plant  employs  one  of  the  most  advanced  techniques  for  its  daily  operations.  SCADA  is  a cloud  based  tool  that  is  developed  for  the  plant  and  helps  the  plant  management  to  monitor  and control  the  daily  activities  at  the  plant  in  the  supply  network.

Diagram Explaination

Level 0 contains the field devices such as flow and temperature sensors, and final control elements, such as control valves.

Level 1 contains the industrialised input/output (I/O) modules, and their associated distributed electronic processors.

Level 2 contains the supervisory computers, which collate information from processor nodes on the system, and provide the operator control screens.

Level 3 is the production control level, which does not directly control the process, but is concerned with monitoring production and targets.

Level 4 is the production scheduling level.


I would like to thank Civil Department of Trinity College of Engineering for conducting the visit to Water Treatment Plant Nigadi. Especially  Meenakshi Khapre mam  & Harshal sir for conducting the visit.

I would also like to thank
Mr.  Praveen  Ladkat Executive  Engineer,  PCMC for allowing us to visit the plant and to grab the pratical experience.


Thursday, 27 April 2017

SCUBA DIVING JOURNEY

1 Maharashtra Naval Unit NCC, Mumbai  conducted  the SCUBA Diving Camp 2014-15 at Command Swimming Pool of the Western Naval Command, Mumbai for the cadets representing all the seven Groups of Maharashtra Directorate. They are Mumbai ‘A’ and ‘B’ Group, Pune Group, Amravati Group, Kolhapur Group, Nagpur Group and Aurangabad Group. This camp includes cadets from Navy, Army and Air Wing from various parts of Maharashtra.

The Main Objectives of Camp :-

•) To expose NCC cadets to SCUBA Diving and Survival at Sea.
•)To build confidence amongst participants to voluntarily undertake waterborne rescue operations like flood relief, natural calamities etc when need arises.
•)To inculcate the spirit of adventure, camaraderie, character building, team work and ability to willingly face adverse conditions & hardships together.
•)To enjoy underwater flora and fauna.
•)To expose cadets to take up diving as a career option.

Camp Selection:

Western Naval Command has extended all facilities for conducting this camp at the Command Swimming pool located in Navy Nagar, Colaba. The Command Clearance Diving Team (Mumbai) has provided Diving equipment and Diving instructors to conduct the camp in both theory and practical classes on Diving. The camp was conducted from 06 Jul to 12 Jul 2014 which included swimming, medical and physical fitness tests. A total of 50 Cadets – 18 Girls and 32 Boys participated in screening and selection, out of which 30 cadets – 10 Girls and 20 Boys were selected for phase II training (which includes the actual exposure to SCUBA Diving) from13 Jul to 26 Jul 2014


Phase 1: Selection Procedure

The selection procedure was divided in 3 parts-

a) Ground Test.
b) Swimming Test.
c)  Medical Test.


Ground Test was conducted at Kholi Stadium at South Coloba in south Mumbai.

The Test includes
1) 2km Run
2) 20 Push Ups (2 sets)
3) 15 Pull ups (2 sets)


Swimming Test was conducted at COMMAND SWIMMING POOL Colocated with Kholi Stadium in South Mumbai.


The swimming test Include a 400m Swim with the time limit of 4 min.


The final test was Medical Test was conducted in INS ASWINI HOSPITAL situated in South colaba. The test was divided in 4 parts.

1) ECG Test.
2) Chest xray test.
3) Ear Audioable test.
4) Chamber test.


The test were conducted to know the potential of cadets whtheir they are physically fit for the traning of Scuba diving.


The day used to start with a 2 km run in kholi stadium. Further we used to deal with ground exercise for next 2 hours.

After ending up with ground sessions for 3 hours. we were granted a break of 10 min.

Then we were taken to the Command Swimming pool and were granted traning on use of scuba diving equipments.

We had traning sessions on using the mask and snorkel.Further we learned the use of fins.

After sucessfully learning use of mask,snorkel and fins. we had a session on how to wear scuba diving equipments in short span. This was the most important session in scuba diving.

Next session was on how to communicate with diver through bells. This communication network in language of bells (ie a Nylon rope tied to shoulder on which is pulled and streched to communicate known as bell). We also had the jump session from 15fts approx.


Also in the evening we had lectures on different topics related to Defence.


On the second last day of camp all the cadets were taken to Naval dockyard to visit the Indian Naval Ship Trishul. It was a great experience to visit the dockward to see the different types of ships, Submarines etc. We were lucky enough to see the Ins Virat Standing in Mumbai Dockyard.

We had sessions on How the Radar system, Sonar System works. We also had sessions on how to circulate within the ship with the help of maps. We also visited the control room of ship from where the ship is been operated.


It was really a great experience to live the navy life at such a young age. I am fortunate to be the part of Scuba diving camp.


Sunday, 26 March 2017

ONE WAY SLABS & TWO WAY SLABS DESIGN.

One Way Slab

One way slabs are such slabs in which the loads are shared only by the shorter direction of the slab. Here ratio of longer span of slab to the shorter span of slab is greater than 2. One way slab being supported on two opposite sides only leads to the structural action in single direction.

Analysis and Design of One-way Slab:

Design steps:

Step 1: Preliminary Design:

Find depth of slab using deflection control criteria.

Take Span/d = 25 for simply supported slab.

= 30 for continuous slab.

D ≥ Dmin = 100mm for normal design.

= 125mm for earthquake resistant design.

Step 2: Analysis of slab:

Analyze the slab considering the slab as beam of 1m width and find respective loads, maximum design bending moment and maximum design shear force.

Step 3: Design of Slab:

Verify depth of slab:


Determine ‘Ast’ and ‘Φ’ and number of bars in shorter direction of slab.
Slab section is normally designed as Singly Reinforced Under Reinforced Rectangular Section.

Ast = Mu/(0.87fy(d-0.416xu)) which should not be less than Astmin.

Check slab for shear.
Step 4: Check slab at limit state of serviceability in deflection.

l/d ≤ αβγδγ

Step 5: Detailing of reinforcement.

Curtail or bent surplus bars.
Check development length at support.
Ld ≤ 1.3Ml / Vu + ld

Provide min. Ast as distribution bars in longer direction of slab.

Two Way Slab

Two way slabs are such slabs in which the loads are shared by both the shorter and longer direction of the slab.Here the ratio of longer span of slab to the shorter span of slab is less or equals to 2. Two way slab being supported on four sides the load will be carried in both the directions.

Analysis and Design of Two Way Slab:

Design Steps:

Step 1: Preliminary Design.

Find depth of slab using deflection control criteria.

Take span/d = 28 for simply supported slab and 32 for continuous slab.

D ≥ Dmin = 100mm for normal design and 125mm for earthquake resistant design.

Step 2: Analysis of Slab.

Slab is analyzed by IS code method. (Ref. Annex D-1 and Annex D-2).

Step 3: Design of Slab.

Verify depth of slab:


Determine ‘Ast’ and ‘Φ’ and number of bars in shorter direction of slab.
Slab section is normally designed as Singly Reinforced Under Reinforced Rectangular Section.

Ast = Mu/(0.87fy(d-0.416xu)) which should not be less than Astmin.

Check slab for shear in shorter direction.

Step 4: Check slab at limit state of serviceability in deflection in shorter direction.

l/d ≤ αβγδγ

Step 5: Detailing of reinforcement:

Curtail/bend the surplus bars as per detailing rules of code. (Ref. Annex)
Check development length at support.
Ld ≤ 1.3Ml / Vu + ld

Provide torsion reinforcement at the discontinuous edge of slab as per codal provision.


Pic credits: Google images.
Info credits: fb page of civil development.


Friday, 24 March 2017

BRICKS- One of the Important Material of Construction.

Bricks

Bricks are the small rectangular blocks typically made of fired or sun-dried clay, typically used in building. The bricks are obtained by moulding clay in rectangular blocks of uniform size and then by drying and burning these blocks. As bricks are of uniform size, they can be properly arranged and further, as they are light in weight, no lifting appliance is required to them. The bricks don’t require dressing and the art of laying bricks is so simple that the brickwork can be carried out with the help of unskilled labours. Thus, at places where stones are not easily available, but if plenty of clay suitable for the manufacturing of bricks, the bricks replace stones.

The common brick is one of the oldest building materials and it is extensively used at present as a leading material of construction because of its durability, strength, reliability, low cost, easy availability, etc.

COMPOSITION OF GOOD BRICKS

Alumina:  It is the chief constituent of every kind of clay. A good brick should contain 20% to 30% of alumina. This constituent imparts plasticity to the clay so that it can be moulded. If alumina is present in excess, with inadequate quantity of sand, the raw bricks shrink and warp during drying /burning and become too hard when burnt.

Silica:  It exists in clay either as free or combined. As free sand, it is mechanically mixed with clay. In combine form, it exists in chemical composition with alumina. A good brick material should contain about 50% to 60% of silica. The presence of this constituent prevents cracking, shrinking and warping of raw bricks. It thus imparts uniform shape to the bricks. The durability of bricks depends on the proper proportion of silica in brick material. The excess of silica destroys the cohesion between particles and the bricks become brittle.

Lime:  A small quantity of lime not exceeding 5 percent is desirable in good brick material. It should be present in a very finely powdered state because even small particles of the size of a pin-head cause flaking of the bricks. The lime prevents shrinkage of raw bricks. The sand alone is infusible. But it slightly fuses at kiln temperature in presence of lime. Such fused sand works as a hard cementing material for brick particles. The excess of lime causes the brick to melt and hence its shape is lost. The lumps of lime are converted into quick lime after burning and this quick lime slakes and expands in presence of moisture. Such an action results in splitting of bricks into pieces.


Oxide of iron:  A small quantity of oxide of iron to the extent of about 5 to 6 percent is desirable in good brick material. It helps as lime to fuse sand. It also imparts red colour to the bricks. The excess of oxide of iron makes the bricks dark blue or blackish. If, on the other hand, the quantity of iron oxide is comparatively less, the bricks will be yellowish in colour.

Magnesia: A small quantity of magnesia in brick material imparts yellow tint to the bricks and decreases shrinkage. However, excess of magnesia leads to the decay of bricks.

QUALITY OF GOOD BRICKS

The good bricks which are to be used for the construction of important structures should posses the following qualities:

1) The bricks should be table-mounted, well burnt in kilns, copper-coloured, free from cracks and with sharp & square edges. The colour should be uniform and bright.

2) The bricks should be uniform in shape and should be of standard size.

3)The bricks should give a clear metallic ringing sound when struck with each other.

4)The bricks when broken or fractured should show a bright homogeneous and uniform compact structure free from voids.

5) The bricks shouldn’t absorb water more than 20 percent by weight for first class bricks and 22 percent by weight for second class bricks, when soaked in cold water for a period of 24 hours.

6) The bricks should be sufficiently hard. No impression should be left on brick surface, when it is scratched with finger nail.

7) The bricks should not break into pieces when dropped flat on hard ground from a height of about one meter.

8) The bricks should have low thermal conductivity and they should be sound-proof.

9) The bricks, when soaked in water for 24 hours, should not show deposits of white salts when allowed to dry in shade.

10) No brick should have the crushing strength below 5.5 N/mm sq.

STRENGTH OF BRICKS

The strength of Bricks is determined by taking following measures into consideration

1) Composition brick making material,
Preparation of clay and blending of ingredients.

2) Nature of moulding adopted
Care taken in drying and stacking of raw or green bricks.

3) Type of kiln used including type of fuel and its feeding.

4) Burning and cooling processes
Care taken in unloading.


As Brick is the most important material part of construction every civil engineer should know the details of Bricks.