September 19, 2020
Page 1
Current Chairman of NAB?
Javed Iqbal
Current Chairman Of FBR?
Javed Ghani
Current Chairman of FPSC?
Haseeb Athar
Saturday, September 19, 2020
Thursday, February 22, 2018
dam
February 22, 2018
Classification of Dams by Material, Use, Hydraulic Design
Grouping of Dams by Material, Use, Hydraulic Design
Dams can be grouped in different courses relying on the motivation behind characterization
Grouping of Dams as per the Material utilized for Dam Construction
Earth Dams
Shake fill Dams
Strong brick work gravity Dams
Praise stone work gravity Dams
Steel Dams
Timber dams
Curve dams
The initial three kinds of Dam are antiquated in root while the last four have come by and large utilize just in the most recent century or somewhere in the vicinity.
Grouping of Dams as per Use
Capacity Dams
Detainment Dams
Preoccupation Dams
Grouping as indicated by Hydraulic outline
Flood Dams
Non-Overflow Dams
Inflexible Dams
Non-Rigid Dams
dam
February 22, 2018
Dams Definition and Uses of Dams
What is Dam
Meaning of Dam is as an obstacle built over a stream or waterway. At the back of this obstruction water is gathered framing a pool. The side on which water is gathered is called upstream side and the opposite side of the boundary is called downstream side. The pool of water which is shaped upstream is known as a Reservoir.
Employments of Dams and Reservoirs
Following are the employments of Dams
The water gathered in the lake can be utilized for amusement, as a store of drinking water or it can be provided to the encompassing ranch arrive through waterways for water system.
The vitality of this gathered water can be utilized to turn a plant to pound wheat or to turn the sharp edges of a turbine to produce electrical power.
In the midst of surges, employments of dams can fill in as securities for the towns and urban communities downstream of the waterway.
Aside from these preferences dams are extremely critical in the midst of war. As they help in arranging war procedures and in controlling the headway of adversary powers.
Meaning of Dam is as an obstacle built over a stream or waterway. At the back of this obstruction water is gathered framing a pool. The side on which water is gathered is called upstream side and the opposite side of the boundary is called downstream side. The pool of water which is shaped upstream is known as a Reservoir.
Employments of Dams and Reservoirs
Following are the employments of Dams
The water gathered in the lake can be utilized for amusement, as a store of drinking water or it can be provided to the encompassing ranch arrive through waterways for water system.
The vitality of this gathered water can be utilized to turn a plant to pound wheat or to turn the sharp edges of a turbine to produce electrical power.
In the midst of surges, employments of dams can fill in as securities for the towns and urban communities downstream of the waterway.
Aside from these preferences dams are extremely critical in the midst of war. As they help in arranging war procedures and in controlling the headway of adversary powers.
dam
February 22, 2018
Factors Affecting Selection of Type of Dam
At whatever point it is chosen to build a dam, the principal question that one face is which sort of dam will be most reasonable and generally temperate? Following are the variables influencing determination of dam site by dam write.
Geography
Geography and Foundation Conditions
Accessibility of materials
Spillway size and area
Seismic tremor zone
Tallness of the Dam
Different factors, for example, cost of development and upkeep, life of dam, style and so on.
Components Affecting Selection of Dam
These elements are talked about one by one.
Geography
Geography directs the primary decision of the sort of dam.
A limited U-formed valley, i.e. a limited stream streaming between high rough dividers, would propose a solid flood dam.
A low plain nation, would recommend an earth fill dam with discrete spillways.
A thin V-molded valley shows the decision of an Arch dam
Topographical and Foundation Conditions
Topographical and Foundation conditions ought to be altogether studied in light of the fact that the establishments need to convey the heaviness of the dam. Different sort of establishments by and large experienced areSolid shake establishments, for example, stone have solid bearing force and relatively every sort of dam can be based on such establishments.
Rock establishments are reasonable for earthen and shake fill dams.
Residue and fine sand establishments recommend development of earth dams or low gravity dams.
Dirt establishments are probably going to cause gigantic settlement of the dam. Developments of gravity dams or shake fill dams are not reasonable on such establishments. Earthen dams after unique medicines can be manufactured.
Accessibility of Materials
Accessibility of materials is another imperative factor in choosing the kind of dam. So as to accomplish economy in dam development, the materials required must be accessible locally or at short separations from the development site.
Spillway Size and Location
spillway arranges the surplus waterway release. The limit of the spillway will rely upon the size of the surges to be by-passed. The spillway is hence substantially more imperative on waterways and streams with extensive surge potential.
Seismic tremor Zone
On the off chance that dam is arranged in a tremor zone, its plan must incorporate seismic tremor powers. The kind of structure most appropriate to oppose seismic tremor stuns without peril are earthen dams and solid gravity dams.
Tallness of Dam
Earthen dams are normally not accommodated statures in excess of 30 m or something like that. For more prominent statures, gravity dams are by and large favored.
Geography
Geography and Foundation Conditions
Accessibility of materials
Spillway size and area
Seismic tremor zone
Tallness of the Dam
Different factors, for example, cost of development and upkeep, life of dam, style and so on.
Components Affecting Selection of Dam
These elements are talked about one by one.
Geography
Geography directs the primary decision of the sort of dam.
A limited U-formed valley, i.e. a limited stream streaming between high rough dividers, would propose a solid flood dam.
A low plain nation, would recommend an earth fill dam with discrete spillways.
A thin V-molded valley shows the decision of an Arch dam
Topographical and Foundation Conditions
Topographical and Foundation conditions ought to be altogether studied in light of the fact that the establishments need to convey the heaviness of the dam. Different sort of establishments by and large experienced areSolid shake establishments, for example, stone have solid bearing force and relatively every sort of dam can be based on such establishments.
Rock establishments are reasonable for earthen and shake fill dams.
Residue and fine sand establishments recommend development of earth dams or low gravity dams.
Dirt establishments are probably going to cause gigantic settlement of the dam. Developments of gravity dams or shake fill dams are not reasonable on such establishments. Earthen dams after unique medicines can be manufactured.
Accessibility of Materials
Accessibility of materials is another imperative factor in choosing the kind of dam. So as to accomplish economy in dam development, the materials required must be accessible locally or at short separations from the development site.
Spillway Size and Location
spillway arranges the surplus waterway release. The limit of the spillway will rely upon the size of the surges to be by-passed. The spillway is hence substantially more imperative on waterways and streams with extensive surge potential.
Seismic tremor Zone
On the off chance that dam is arranged in a tremor zone, its plan must incorporate seismic tremor powers. The kind of structure most appropriate to oppose seismic tremor stuns without peril are earthen dams and solid gravity dams.
Tallness of Dam
Earthen dams are normally not accommodated statures in excess of 30 m or something like that. For more prominent statures, gravity dams are by and large favored.
civilenggmaterial
February 22, 2018
Treatment of Wooden Sleepers
Treatment of Wooden Sleepers
Untreated railroad sleepers are inclined to assault by rot and vermin. The life of untreated wooden sleepers is consequently less. The life of untreated sleepers can be drawn out extensively b treatment. An additional existence of 30-half is evaluated for treated railroad sleepers over untreated rail line sleepers.
The strands of wood contain a large number of moment cells containing juices. At the point when these juices age, they prompt rot of timber. In the treatment procedure these juices are expelled as much as cells are loaded with some saving arrangement. The safeguarding arrangements might be oil or some salt arrangement.
The treatment procedures can be classes:
Treatment by creosote oil
Treatment by salt arrangements
Treatment warming under strain
Painting
Treatment by Creosote Oil
It is otherwise called creosoting. In this procedure the railroad sleepers are put in a chamber of around 90" length and 6" measurement and are warmed upto 175oF. A vacuum juices, a short time later, creosote oil can be connected in two ways:Full cell process In this procedure without crushing the vacuum, creosote oil is drawn into the barrel at a weight of 75-150psi. every one of the cells are in this way loaded with the oil along these lines giving the name full cell procedure to the treatment. Around 10-15 lbs of oil for every cubic foot is required in this procedure.
Discharge cell process in this procedure, air is first constrained into the cells took after by oil under strain. Less oil is utilized as a part of this procedure. At the point when the weight is discharged some oil is constrained out by the entangled air. In this technique sleeper does not overflow oil. The railroad sleepers treated with this technique are broadly utilized as a part of Pakistan. It opposes the vermin and rot assault for the duration of its life and the life is extensively expanded.
Treatment by Salt Solution
In this procedure not weight is utilized but rather a sleeper is absorbed the salt arrangement over a long stretch two sorts of salts are for the most part utilized i.e. Zinc Chloride. The procedure is called burnetising process if the previous salt arrangement is utilized and is called kyanisizing process if the later salt arrangement is utilized.
The salt arrangement treated railroad sleepers are less expensive and does not require costly plants but rather the arrangements are probably going to be washed far from sleepers by rain water. Besides the salts are toxic and have more serious peril towards work taking care of them.
Warming under strain
In this procedure sleepers are subjected to high temperatures and weights. The common juices are rendered innocuous by this technique.
Painting
Infrequently untreated sleepers are painted. It weights timber by keeping the passage of dampness into the wood as long as the paint is in place. The closures ought not be painted as it prompts rot known as dry decay. It isn't a productive procedure of treating sleepers.
Untreated railroad sleepers are inclined to assault by rot and vermin. The life of untreated wooden sleepers is consequently less. The life of untreated sleepers can be drawn out extensively b treatment. An additional existence of 30-half is evaluated for treated railroad sleepers over untreated rail line sleepers.
The strands of wood contain a large number of moment cells containing juices. At the point when these juices age, they prompt rot of timber. In the treatment procedure these juices are expelled as much as cells are loaded with some saving arrangement. The safeguarding arrangements might be oil or some salt arrangement.
The treatment procedures can be classes:
Treatment by creosote oil
Treatment by salt arrangements
Treatment warming under strain
Painting
Treatment by Creosote Oil
It is otherwise called creosoting. In this procedure the railroad sleepers are put in a chamber of around 90" length and 6" measurement and are warmed upto 175oF. A vacuum juices, a short time later, creosote oil can be connected in two ways:Full cell process In this procedure without crushing the vacuum, creosote oil is drawn into the barrel at a weight of 75-150psi. every one of the cells are in this way loaded with the oil along these lines giving the name full cell procedure to the treatment. Around 10-15 lbs of oil for every cubic foot is required in this procedure.
Discharge cell process in this procedure, air is first constrained into the cells took after by oil under strain. Less oil is utilized as a part of this procedure. At the point when the weight is discharged some oil is constrained out by the entangled air. In this technique sleeper does not overflow oil. The railroad sleepers treated with this technique are broadly utilized as a part of Pakistan. It opposes the vermin and rot assault for the duration of its life and the life is extensively expanded.
Treatment by Salt Solution
In this procedure not weight is utilized but rather a sleeper is absorbed the salt arrangement over a long stretch two sorts of salts are for the most part utilized i.e. Zinc Chloride. The procedure is called burnetising process if the previous salt arrangement is utilized and is called kyanisizing process if the later salt arrangement is utilized.
The salt arrangement treated railroad sleepers are less expensive and does not require costly plants but rather the arrangements are probably going to be washed far from sleepers by rain water. Besides the salts are toxic and have more serious peril towards work taking care of them.
Warming under strain
In this procedure sleepers are subjected to high temperatures and weights. The common juices are rendered innocuous by this technique.
Painting
Infrequently untreated sleepers are painted. It weights timber by keeping the passage of dampness into the wood as long as the paint is in place. The closures ought not be painted as it prompts rot known as dry decay. It isn't a productive procedure of treating sleepers.
civilenggmaterial
February 22, 2018
Railway Sleepers Density
What is Sleeper Density
The quantity of railroad sleepers required to be set under the track per rail length is called as its rail line sleepers thickness.
It is by and large given by the recipe
Sleeper Density = n + x
where
n = length of one rail in yards
x = abundance number of railroad sleepers
for instance, if there are 19 railroad sleepers in a 14 feet (14 yards) rail at that point
Sleeper Density = n + x = 19
In any case, n = 14
Sleeper thickness = n + 5
In Pakistan the sleeper thickness changes from n + 3 to n + 7. In America, the sleeper thickness from n + 9 to n + 11.
Step by step instructions to Decide Sleeper Density
The accompanying focuses ought to be remembered while choosing about the railroad sleeper thickness
The separating of railroad sleepers in a track relies upon factors given underneath
Horizontal push of trains
Pivot stack coming
Nature of railroad sleepers
The firmness of a track is expanded by expanding weight of rail or by expanding the railroad sleeper thickness and the selection of it is possible that one or different techniques rely upon similar cost of rails and rail route sleepers.
The sleeper thickness can't be expanded inconclusively as a specific least separation is required between the two adjoining sleepers for pressing balance.
If there should arise an occurrence of stunned joints on cure an additional sleeper is to be set up as sleepers are to be given on either side of joint.
All sleepers require not be set at parallel separation separated. Sleepers at rail joints are put ever closer somewhere in the range of a few railroad sleepers close to the joint sleepers are dispersed nearer than the sleepers in the rest of the length of rail.
The quantity of railroad sleepers required to be set under the track per rail length is called as its rail line sleepers thickness.
It is by and large given by the recipe
Sleeper Density = n + x
where
n = length of one rail in yards
x = abundance number of railroad sleepers
for instance, if there are 19 railroad sleepers in a 14 feet (14 yards) rail at that point
Sleeper Density = n + x = 19
In any case, n = 14
Sleeper thickness = n + 5
In Pakistan the sleeper thickness changes from n + 3 to n + 7. In America, the sleeper thickness from n + 9 to n + 11.
Step by step instructions to Decide Sleeper Density
The accompanying focuses ought to be remembered while choosing about the railroad sleeper thickness
The separating of railroad sleepers in a track relies upon factors given underneath
Horizontal push of trains
Pivot stack coming
Nature of railroad sleepers
The firmness of a track is expanded by expanding weight of rail or by expanding the railroad sleeper thickness and the selection of it is possible that one or different techniques rely upon similar cost of rails and rail route sleepers.
The sleeper thickness can't be expanded inconclusively as a specific least separation is required between the two adjoining sleepers for pressing balance.
If there should arise an occurrence of stunned joints on cure an additional sleeper is to be set up as sleepers are to be given on either side of joint.
All sleepers require not be set at parallel separation separated. Sleepers at rail joints are put ever closer somewhere in the range of a few railroad sleepers close to the joint sleepers are dispersed nearer than the sleepers in the rest of the length of rail.
civilenggmaterial
February 22, 2018
Railway Sleepers – Types of Sleepers
Railway Sleepers – Types of Sleepers
Contingent on the situation in a railroad track, rail route sleepers might be delegated:
Longitudinal Sleepers
Transverse Sleepers
1. Longitudinal Sleepers
These are the early type of sleepers which are not usually utilized these days. It comprises of chunks of stones or bits of woods set parallel to and underneath the rails. To keep up rectify measure of the track, cross pieces are given at normal interims.
At display this sort of sleepers are disposed of predominantly in view of the accompanying reasons.
Running of the prepare isn't smooth when this kind of sleepers is utilized.
Clamor made by the track is extensive.
Cost is high.
2. Transverse Sleepers
Transverse sleepers presented in 1835 and from that point forward they are all around utilized. They expel the disadvantages of longitudinal sleepers i.e. the transverse sleepers are sparing, quiet in activity and running of the prepare over these sleepers is smooth. Contingent on the material, the transverse sleepers might be arranged as:Timber/wooden sleepers
Steel sleepers
Cast Iron Sleepers
Solid Sleepers
- Timber or Wooden Sleepers
The timber sleepers about satisfied every one of the prerequisites of perfect sleepers and henceforth they are generally utilized. The wood utilized might resemble teak, sal and so on or it might be coniferous like pine.
The notable highlights of timber/wooden sleepers with points of interest and impediments.
Points of interest of Timber Sleepers
They are much helpful for substantial burdens and high speeds
They have long existence of 10-12 years relying on the atmosphere, condition, rain, power, nature of movement, nature of wood and so forth
Great separators and thus useful for track circuited railroad tracks
They can suit any measure
Reasonable for salty locales and seaside territories
Can be utilized with any area of rail
Can be dealt with and set effectively
They are not seriously harmed if there should arise an occurrence of crash
They are not consumed
Less expensive than some other kinds of sleepers
Weaknesses of Timber Sleepers
Obligated to be assaulted by vermin thus, they should be legitimately treated before utilize
Obligated to burst into flames
They don't avoid crawl
They are influenced by dry and wet decay
End up costly step by step
Life is shorter contrast with others
Steel sleepers
They are as steel trough upset on which rails are settled specifically by keys or stray pieces and utilized along adequate length of tracks.
Points of interest of Steel Sleepers
Have a helpful existence of 20-25 years.
Free from rot and are not assaulted by vermins
Association amongst rail and sleeper is more grounded
Association amongst rail and sleeper is straightforward
More consideration isn't required in the wake of laying
Having better parallel inflexibility
Great piece esteem
Appropriate for high speeds and load
Simple to deal with
Great protection against crawl
Hindrances of Steel sleepers
Subject to erosion by dampness and ought not on the grounds that in salty areas
Great covers and henceforth can't be utilized as a part of track circuited districts
Can't be utilized for all areas of rails and measures
Ought not be laid with some other sorts of counterbalance aside from store
Costly
Can seriously harmed under crashes
Way check is gotten if the keys are over driven
The rail situate is weaker
Having great safeguard as there isn't pad between rail foot and weight
Cast Iron Sleepers
They comprise of two pots or plates with rib and associated by created press tie bar of segment of around 2″ ½" each pot or plate is set beneath each rail. The pot is oval fit as a fiddle with bigger distance across 2′-0″ and littler width 1′-8″ is favored. Plate sleepers comprise of rectangular plates of size around 2′ – 10′ x 1′ – 0″.
The relative favorable circumstances and impediments are given underneath.
Favorable circumstances of Cast Iron Sleepers
Long life upto 50-60 years
High rub an incentive as they can be remolded
Can be fabricated locally
Given adequate bearing zone
Substantially more grounded at the rail situate
Counteract and check crawl of rail
They are not assaulted by vermin
Hindrances Cast Iron Sleepers
They are inclined to consumption and can't be utilized as a part of salty arrangements and beach front regions
Not reasonable for track circuited segments of railroads
Can seriously harm under wrecking
Hard to keep up the measure as the two pots are free
Require a substantial number of affixing materials
Hard to deal with and might be effortlessly harmed
Absence of good safeguard
They are costly
Solid sleepers
R.C.C and pre-focused on solid sleepers are currently supplanting every single other kind of sleepers but to some uncommon conditions, for example, crossing spans and so forth here timber sleepers are utilized. They were as a matter of first importance utilized as a part of France indirect in 1914 yet are normal since 1950. They might be a twin piece sleepers joined by a point press. It might be a solitary square pre-focused on type.
Preferences Concrete Sleeprs
Tough with life extend from 40-50 years
They can be created on expansive amounts locally by introducing a plant
Heavier than every other kind in this manner giving better horizontal soundness to the track
Great separators and subsequently appropriate for use in track circuited lines
Effective in controlling wet blanket
They are not assaulted by erosion
Free from assaults of vermin and rot, appropriate for a wide range of soils
Most appropriate for welded tracks
Anticipate clasping all the more proficiently
Starting expense is high however ends up being conservative in long run
Successfully and emphatically hold the track to measure
Inflammable and heat proof
Hindrances Concrete Sleepers
Hard to be dealt with
Hard to be fabricated in various sizes along these lines can't be utilized as a part of extensions and intersection
Can be harmed effortlessly while stacking and emptying
Featured Post
Materials for Ballast
1. Broken Stones 2.Gravels 3.Cinders / Ashes 4.Sand 5.Kankar 6.Moorum 7. Brick Ballast
