Steel

civil techniques

Classification of Sleepers

abbu riyaz 1 May, 2023

There are many Classification of Sleepers. Sleepers classify according to the materials uses in the construction of railway rail tracks. The sleepers are of concrete, timbers, steel, cast iron, RCC, and the Prestress concrete. In these various types of sleepers, the sleeper which is economic uses in the construction of railway tracks.

And the climatic and geological considerations considers in making a decision of using the type of sleeper according to needs. The classifications of sleepers are as follows,

Classification of Sleepers

There are Many types of sleepers makes in the construction of the railway tracks.

Wooden Sleepers
Metal Sleepers
Concrete Sleepers

1. wooden Sleepers

wooden Sleepers are the old traditional material used in the construction of railway track sleepers. It Satisfies all requirements of a good sleeper. It absorbs shocks and vibration due to heavy moving loads. The life of wooden sleepers depends on many facts like wear and tear, decay, and attack by termites, etc.

In the Railway bridges, the railway rail tracks are of wooden sleepers. It is because of its less weight, high load carrying capacity and its tendency to absorb shocks and vibrations.

2. Metal Sleepers

The Metal sleepers are of cast iron and steel. Metal sleepers use widely in the modern construction of railway tracks. Cast iron is widely engaging than steel because of its less tendency to corrosion. Metal sleepers use widely because of the shortage of wooden sleepers and its long life properties.

3. Concrete Sleepers

The Concrete sleepers are using more than any other sleepers because of its unique properties. They are more resistant to wear and tear. It withstands blows and vibrations cause due to heavy moving loads. And it is fewer subjects to chemical attacks, termite attacks, and more corrosion resistance.

There are two types of sleepers they are,

Reinforced Concrete sleepers
Pre-stressed Concrete sleepers

civil techniques

Railway Track Sleepers

abbu riyaz 1 May, 2023

Railway Track Sleepers are members which lay transverse to the rails on which the rail supports and fixes. Sleepers are concrete beds in the railway tracks. The sleepers are of concrete, timbers, steel, cast iron, RCC, and the Prestress concrete. The main role of sleepers is to transfer load from rails to the ballast. And the sub-grade below. It as a transverse member throughout the permanent way.

These sleepers fix vertical to each other. It fixes throughout the track. The main work of sleepers is to hold rails in a strong position. It receives the loads from rails and spread to ballast and sub-grades.

Functions of Railway Track Sleepers

Sleepers perform the following functions

It holds the rails at the proper gauge and at the proper level, flat curves, turnouts, and in diamond crossings.

Transfers load evenly from rails to ballasts to absorb vibrations of moving loads.
Provides a good stability of track.
The track circuiting is making easy with it.
Supports the rail tracks at proper super-elevation.
It acts as an elastic medium in between the ballast and the rails to absorb blows.
It maintains the horizontal and vertical alignments throughout the entire track for a long lifetime.
They provide a way to rectify track geometry during its use.

Requirements of Railway Track sleepers

For a long time period and for a good performance the sleepers need to some important requirements.

Sleepers must be economical.
Should have a low maintenance cost.
It should be easier to handle during the maintenance operations like lifting, packing, removal, and replacement.
The weight of sleepers should not be too heavy or too light. It should have a moderate weight for ease of access.
And capable to resist shocks of rails because of a fast-moving load with vibration.
It should have a proper spacing between two sleepers for ease of maintenance for removal and replacement.
Sleeper to design in a way that they should not push out easily due to moving loads.
A sleeper to provide with anti-theft qualities.

civil techniques

Railway Rail Tracks

abbu riyaz 1 May, 2023

Railway Rail Tracks are the main important components in tracks. Rails are unsymmetrical I-sections. It composes of steel. Rails lay parallelly over sleepers. Railway Rail Track lies parallel to the entire track. Rails carry the wheel load of trains providing them a smooth way. And transfer the load safely to sleepers.

These rails are of high carbon steel to resist and withstand wear and tear. Rails joints together longitudinally with welding and with fishplates.

Functions of Railway Rail Tracks

Rails in the Railway Track serves the following purposes:

Rails transfer loads from wheels safely to sleepers and ballasts.
Provides a smooth level surface for movement of trains.
Provides an unchanging surface for passage of heavy moving loads with minimum friction between steel rail and wheels.

It guides the wheel of trains throughout the trackway.
High carbon steel has high strength, stiffness, and durability.
The web of rail is strong enough and support head of rails.
Rails acts as girders and bear stress develop by heavy vertical/lateral loads, breaking force and thermal stress.

Length of Railway Rail Tracks

Longer rails are highly economic. And it gives a high strength. Joints are weak points in Railway Rail Tracks. So long rails consider mainly than short rails. Short rails consume more rail joints. This decrease the efficiency of rails. These rails joints with welding and by fish plates.

In the modern railways with the technological advancement, keeping gaps between rails avoids. The welding of rails introduces. These rails welds into three rails, five rails and ten rails. Welding of jointing rails is by melting them together. These welding rails has many advantages. It is economical, low maintenance, increase stability, reduce creeps. Creeps are longitudinal movement of rail tracks. It is common to all railway rail tracks. It measures regularly in rail tracks. A creep of up to 150 mm permits in rail tracks.

Construction materials

Railway Track Components

abbu riyaz 1 May, 2023

There are some important Railway Track Components in the construction of railway track. The railway track is a permanent way for all trains. A railway track is a combination of rails, sleepers, ballast, and subgrades. The systematic rails fit on a number of sleepers. This sleeper rests on ballast supports by subgrades. These rails fix or welds together by a component name as fishplates.

The trach consists of two parallel rails fix at a specific distance. This distance depends upon the gauge of tracks. These rails are parallel to each other.

Railway Track Components

A Railway Track has many Components in it. they are as follows,

Rails
Sleepers
Ballast
Formations or subgrades

A good quality and strong aggregate materials, steel I section to use in the construction of railway tracks.

1. Rails

Rails are the first main element in the Railway Track Components. It is of an I section make with steel. Two rails fix opposite to each other. These rails are vertical I section elements places vertically throughout the track. It lies parallel to the entire track. It carries the wheel load of trains providing them a smooth way. And transfer the load safely to sleepers.

2. Sleepers

Sleepers are concrete beds in the railway tracks. It is the second main important thing in Railway Track Components. Sleepers are of concrete, timbers, steel, cast iron, RCC, and prestress concrete. These sleepers fix vertical to each other. It fixes throughout the track. The main work of sleepers is to hold rails in a strong position. It receives the loads from rails and spread to ballast and subgrades.

3. Ballast

Ballasts are stone, aggregates, and gravels. these places below and around the sleepers. The main work of ballast is to hold sleepers and rails. And provides them a strong grip. Stone ballasts widely use in railway tracks in modern railways.

4. Formations or subgrades

These are natural soils on the bottom of a track. These are the foundations of tracks. It holds rails, sleepers, ballast and the entire track together. It supports the railway track from the bottom layer.

civil techniques

Scaffolding

abbu riyaz 1 May, 2023

Scaffolding is a temporary structure uses in building operations to support platforms for workmen. And helps with structural materials, and materials required during construction of high rise buildings. It uses for above height of 1.5 meters. This temporary scaffold is useful in building construction, repairs, demolition, maintenance and repair works.

It sets one or both sides of the wall according to needs. It sets one side of wall or buildings for ordinary works. For major quality works scaffold to sets on both sides of walls. The height of the scaffolding is adjusting according to the work.

Components of scaffolding

Standards
Ledgers
Braces
Planks
Put-logs
Guard boards
Toe-boards

Standards: These are vertical members of the scaffolding.

Ledgers: Ledgers are horizontal members at right angles to the standards and parallel to the wall.

Braces: Braces are members fix diagonally to the standards.

Planks: They forms the horizontal platforms for supporting men, materials, and appliances.

Put-logs: These members place on horizontal members at right angles to the wall.

Guard boards It uses at working level to guard against materials.

Toe-boards Toe-boards place parallel to the ledgers and using for protection at high levels of the working platform.

These components/members of the scaffold are secure by means of rope lashings, rails, and bolts.

Advantages of scaffolding

The first advantage of using scaffold is to complete the work task safely.

Easily installs and complete various work tasks without hassle.

With scaffold, the worker can reach many meters high as possible.

It provides large space to keep your construction tools and more usable workspace.

LIghtweight and cost-effective.

It is easier for workers to maintain their balance on a flat platform than on a ladder step.

Provide access to difficult places when buildings are constructs and reduce time to complete work.

civil techniques

RCC Column Construction Methods

abbu riyaz 1 May, 2023

RCC Column Construction Methods consist of various steps and procedures to follow in the construction of columns at the site.

RCC Column Construction Methods

Layouts
Reinforcement work
Formwork
Pouring of concrete

1. Layout

Layouts proceed by surveying instrument. After marking the grid lines, the location of columns Identifies and marks.

2. Reinforcement work

Checklist for Column reinforcement works on site:

Check the numbers and diameter of vertical bars
The spacing between vertical bars
Development length which depends on the diameter of the bar
Lapping in alternate bars to come at the same height and not coming inside beam or slab.
Lapping l/3 or 2l/3 of column
The spacing between stirrups
The hook bends properly at right angles
Check the stirrups corner

3. Formwork

Columns carry a load of the structure so it is critical. It is important to align column for verticality so that load transmits properly. The column shuttering should strong enough to take the pressure of fresh concrete and remain in position during concreting.

Guidelines on column shuttering

Holding the concrete shuttering firmly in place and for proper alignment, a concrete pad is cast before fixing the shuttering. The starter cures for a day or two so that it is hard enough to fix the shuttering around it.
Column box or shuttering for columns is made of plywood sheets or steel sheets fabricators with adequate stiffeners.
Thin films of oil/grease applies to the inner surface of shuttering to easily remove from a column. After the concrete hardens.
Shuttering is properly aligns with its verticality and diagonals are checks to ensure accuracy in dimensions.
Formwork thoroughly supports with props size before pouring the concrete. So that it does not move horizontally or vertically during concreting.
Gaps in shuttering joints to seal with plaster or a piece of wood to prevent leakage an of a slurry.
Appropriate space to provide in the inner face of the shutter and reinforcement by fixing cover blocks.
It is preferable to remove shutters after 24 hrs of casting. If need to remove earlier, it should not remove within sixteen hours.
The removal of shutters is handling gently without jerks so that edges of columns will safe without damages.
supports of column shuttering to prevent from moving during concreting.
Diagonals of the shuttering to check to ensure dimensional accuracy.

4. Concreting of RCC Column

Concreting of an RCC column is by two methods

Manually
With the help of machine or pump

Points to follow during and after concreting:

For less quantity machine mix concrete adopts and for larger quantity, ready-mix concrete (RMC) orders.
Approval of placing concrete whether by pump or manually from the client.
Concrete pours up to slab bottom; the remaining column gets concrete during pouring of slab & beam.
Mechanical vibrator to compulsorily use in the column but excess vibration cause segregation. Each layer is to compact thoroughly.
Target slump to be 160 mm.
The height of pouring concrete should not exceed 1.5 m.
Avoid construction joint in the column.
check proper cover.
The temperature should be below 30 degrees while pouring concrete.
After the pouring and vibrating, the horizontality and verticality of the column to check.