KNOWLEDGE EXCHANGE

Having a house of your own where you live happily with your loved ones is a dream that everyone has – a desire that everyone cherishes. Let us understand what is the importance of a house or a home in a person's life? Your house is a protective shield for you:-

1. It saves you from the forces of nature

  • Scorching heat in summer
  • Harsh cold in winter
  • Strong winds during a storm
  • Heavy rain in monsoon

2. It protects you from the dark side of human nature-crimes like theft or robbery.

Your house is like your own space in this huge world. Where things happen your way. You create memories with your loved ones – share joys and sorrows. What an important structure a house is – it keeps you, your family and your belongings protected. So is it not important that it should be very strong from inside? In fact house is just like a human body. Our body has to be strong from inside to be able to handle routine functions of life upto old age till we live. The human body as we see it from outside is actually very complicated from inside. It has several organs which are resting on a structure called skeleton which is the actual strength of the body. In the same way a house is resting on a structure made of columns, beams and slabs.

These columns, beams and slabs are made of various items which are:-

  • Steel bars
  • Binding Wires
  • Stirrups
  • Cover Blocks
  • Lintel Beams
  • Chairs

All these products are very important and are put together to form a steel cage. This cage is put in place and casted with cement inside and outside of it. Due to very good bonding between the steel cage and the surrounding concrete a sold structure gets formed which called RCC (Reinforced Cement Concrete). It is this structure which bears the entire load of a building and gives it strength to serve the purpose it is built for.

Now that we have known the importance of good quality RCC in a house we obviously need to think about its constituents. We need to consider 3 points in particular –

  • The quality of the various products that are constituents of RCC.
  • The quality of workmanship at the time of fixing of these products at site.
  • The designing and placement of the steel structure based on which the columns, beams and slabs are fabricated and erected at the site.

Keeping in mind all these 3 points, we bring you complete steel reinforcement solutions which is a THREE pronged strategy to give you excellent quality of RCC work for your house/building:-

  • All 6 components required for steel cage formation are supplied by us of very high quality.
  • A panel of efficient company certified contractors made available to do steel cage formation work at site as per civil engineering requirements at your site.
  • A panel of civil engineers to cater to your structural designing needs based on optimal utilization of the space available.If you Already have structural drawings we can them.

We now elaborate the role of each of the products used at the time of steel reinforcement work at a construction site.

TMT Steel bars

Application of TMT Steel Bars as shown above.

This is the main component of the steel cage that is used for making columns, beams and slabs in a house. These steel bars should have a combination of high strength, ductility and corrosion resistance and have good bonding with cement at the time of casting. These properties will help to give a solid RCC structure to take the load of a building.


Binding wires

Application of Binding Wires as shown below.

This will keep the bars in place as required in the structural design. Loosely tied knots or bad quality wire can gravely weaken the entire structure.



STIRRUPS (Rings)

Application of STIRRUPS (RINGS) as shown above.

Most columns and beams in building today have 5-20 pieces of steel bars in them. These bars need to be connected together with stirrups so that they do not spread out at the time of pouring concrete. In many cases rings are made at site with scrap steel which has two disadvantages.

  • The length of the steel is not adequate to make full rings
  • The bending angles are not accurate resulting in loose rings. Much care is also not given to proper tying with the main bars resulting in weakening of the Steel cage.

Cover Blocks

Application of Cover Blocks as shown above.

Although steel used in TMT bars is a very strong metal but it has an enemy –MOISTURE. When steel bars come in contact with moisture they get rusted and loose strength, weakening the structure.

In order to overcome the problem, a uniform cover of cement has to be put on the steel. This is where cover blocks play a very important role. They help to maintain proper gap between the steel bars and shuttering so that when concrete is poured onto the cage, it gives the bar a uniform covering of the required thickness.
At many sites it has been noticed that either cover blocks are not being used or sometimes stone grit is placed under the steel bars to serve this purpose. Such malpractices leave the steel bars vulnerable to attack by moisture leading to corrosion and damage to the bar leading to week structure.

It is also important to note that if cover blocks are made at site they do not have the required strength as that of concrete being poured and will crumble at the time of use under the vibration load of needle vibrators.

Lintel Beam Kits

When we construct a house, doors and windows are provided to give access to the house and make it airy, sunny and well lighted. At the time of leaving space for doors and windows, a beam has to be placed above the open space left for this purpose. This beam called LINTEL BEAM is placed to take the load of the wall above the frame as shown in the picture.

Ideally a lintel beam has to cover the opening on both ends upto 6 inches. It comprises of top and bottom bars tied with rings and binding wire with cover blocks placed at positions as shown.

Application of Lintel Beam Kits as shown above

However at most sites, they are made by using scrap steel bars of inadequate length and improper tying leading to weak beam that will not support the weight of the wall above for a long time. We therefore have introduced lintel beam kits where all items used for making one beam are put together, cut to an accurate size. They only have to be assembled, placed over the sill and casted giving accurate lintel beams.


Steel Chairs

In order to maintain the gap between top and bottom reinforcement steel chairs as shown are inserted at fixed distances.

Application of Steel Chairs as shown below:

Steel chairs are very important component of rafts and slabs. The top reinforcement is placed on the chairs which are resting on the base/ bottom reinforcement. The entire weight of the top reinforcement is supported by it. In a way the bottom reinforcement is supported by COVER BLOCKS and the top one by CHAIRS. Inadequate use of chairs can cause buckling of the top reinforcement.

PROPER DESIGN

For proper designing of the structure, one should consult a good architect/structural engineer. A professional structural engineer /consultant take care of all the safety and economical factors while designing. The structural consultant gives complete instructions about the important points which have to be followed before permitting pouring of concrete.

Designing is done, depending upon the weight (load-bearing capacity) of the structure. The diameter, spacing and angle of the bars are taken into account while designing.

T - BEAM Details of reinforcement.

RCC slab supported on T - BEAMS.

An ideally designed building should:

  • Have adequate strength to bear load of the building.
  • Have required elasticity to withstand earthquakes, shocks and other calamities.
  • Be sturdy enough to bear all types of climate changes like rainfall, strong wind, extreme heat & cold conditions.

EFFICIENT WORKMANSHIP

After designing your dream home, and sourcing good quality material, you need a competent contractor and skilled labor. Semi-skilled or unskilled work force can ruin your house, if:

  • The bars have been cut, but haven't been bound properly with binding wire.
  • Likewise, the ring in column or beam not bound properly at proper distance.
  • The splicing of rebars in column or beam not in staggered pattern will make the structure weak.
  • Cover Blocks have not been tied with the bars properly at proper distance.
  • Anti-rust compound not applied adequately on the whole Structure, resulting in rusting of the steel due to moisture.
  • Shuttering work has not been carried out correctly, causing the steel to remain uncovered at certain places.

We endeavor to buy good quality of products required in the construction of a building. This is one of the important factors but to get a good job done, one has to take care of the workmanship during the construction which surely depends on the skill of the laborers and supervisors with an eye on the following points.

  • The shuttering work shall be strong enough to take the load of skeleton of steel and the concrete poured on it.
  • Shuttering shall be leveled as per the requirement and drawings.
  • We should ensure that the steel is provided with cover blocks of required strength to protect the steel after pouring of concrete on it.
  • The cover blocks should be properly placed i.e. 1m to 1.5m centre to centre as per the Indian Standards. As a thumb rule minimum cover of 50mm (2") in footing foundation, 30/40mm in columns, 25mm in Beams and shear walls and 20mm in slabs may be ensured.
  • Sufficient lap length as specified and directed should be ensured. Usually it is 50 times the diameter of the bar is considered safe.
  • Proper steel chairs should be used for separating the top and bottom steel cage reinforcement as per the drawings provided.
  • Steel reinforcement should be placed and tied properly with binding wire such that concrete placement is possible without segregation and compaction possible by an immersion needle vibrator which is used for compacting the concrete.

In order to take care of all these factors it is important to have a good and efficient contractor with skilled workforce to do the job as required.

Poor workmanship can give such risks to the structure: Poor construction methods and workmanship is responsible for the failure of buildings and structure. The poor construction methods and workmanship is caused due to negligence and inadequate quality control at construction site. Our purpose is to provide the right information, facilitating a good and strong construction. And help you to take right decisions, while constructing your dream home.

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