Understanding Stresses and Modular ratio | RCC Structures

Stresses in Steel and Concrete | Building Construction

In one of our previous articles, we discussed “Basic definitions and formulas”.

Now we will move on with our discussion on “Permissible stresses in concrete and steel” and “Understanding Modular ratio”.

Permissible Stresses in Concrete

Reinforced concrete designs make use of M15 grade concrete. The permissible stresses for different grades of concrete is different. They are given below:

Sr. No. Concrete Grade M15 M20 M25 M30
1. Stress in compression

  1. Bending


5 7 8.5 10
  1. Direct


4 5 6 8
2. Stress in bond (average) for plain bars 0.6 0.8 0.9 1.0
3. Characteristics compressive strength 15 20 25 30

 Also refer for other values in IS:456-1978

Permissible Stresses in Steel

The permissible stresses for different grades of steel are given in the table above.

The different grades steel available in the market with their market names are as follows:

Mild Steel

Grade I steel is known as mild steel. The abbreviation used for Mild steel is (m.s.)

High Tensile deformed steel has two types. They are as follows:

  1. Grade Fe415 (Tor-40 or Tistrong I)
  2. Grade Fe500 (Tor-50 or Tistrong II)

The names of the high tensile deformed steel have been derived from their manufacturers.

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Conduits | Building Construction

Construction of Conduits | Civil Engineering

In the previous article, we discussed “Types of Underground Conduits”. Now we will proceed with our discussion on “Construction of Conduits”.

Underground conduits can also be termed as buried conduits. They are constructed in variety of shapes with different materials used for construction.

Load on the conduit

The characters of the conduit determine the load withstanding capacity of the conduit. They are as follows:

  • Material of the conduit
  • Shape
  • Type of the support

For example:

If we take the example of a concrete conduit (rigid material), the load that the concrete conduit can withstand would depend on the following:

  1. Strength of the concrete pipe
  2. Quality of the foundation bedding

How to determine the strength of the conduit?

A three edge bearing test has to be conducted in order to determine the strength of the conduit.

Three edge bearing test
Three edge bearing test

This test simulates a very severe loading condition which would rarely occur in the actual conduits. This helps us determine the maximum load the conduit can take. It has been seen that the conduits can take greater load than that obtained in the test.

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Types of Underground Conduits | Civil Engineering

Underground Conduits

What are conduits?

Conduits have different meanings in different subjects.

For example:

Geographically, conduits could refer to a channel carrying water, underground tunnel or waterway (river or canal).

In terms of electrical systems, it may refer to an electrical conduit, HVAC (duct) etc.

Electrical Conduits
Electrical Conduits

We are referring to the conduits which is laid underground and used for variety of purposes.

For example:

  • Sewers
  • Drains
  • Culverts
  • Water mains
  • Gas lines
  • Electrical cables
  • Telephone lines

Causes of Foundation Damage and Retrofitting | Settlement in the ground

Causes of Foundation damage and Retrofitting 

In one of my previous articles, we discussed various steps in which the survey of the foundation has to be done in order to be considered for retrofitting.

In this article, we will discuss various reasons or causes for the damage of the foundations.

Types of foundation damage can be classified as follows:


  1. Natural rock
  2. Brick



Moisture damage

  1. Frost wedging
  2. Salt bloom

Settlement in the ground

  1. Groundwater lowering
  2. Limited bearing capacity of the ground (land)
  3. Uneven bedrock depth
  4. Excavations performed below the foundations and poor quality of backfill
  5. Increased load on the ground leading to failure
  6. Damage to the neighbouring houses
  7. Horizontal movement occurring in the ground

 Frost heave/adfreezing

Alum shale

Now we will move on with the discussion in detail on the types of foundation damage occurring due to Settlement in the ground.

Lowering in the Groundwater level

When the buildings are built on compressible soils, the resulting stress on the soil causes the soil to compress. Raft foundations are used in these kind of soils.

Since the soil undergoes compression the upper portion of wooden piles rot when groundwater level sinks.

There are various conditions which can cause the changes in the groundwater level or pore water pressure. They are as follows:

  • Ice Static Rebound
  • Dewatering (seen in cities)
  • Ditches and pipes below the groundwater level
  • Deep Foundations and Basements (causing further drainage of the ground
  • Tunnelling
  • By the removal of foundation sills
  • Construction of non-permeable surfaces such as roads, pathways causing the least amount of natural precipitation
  • Use of deciduous trees should be avoided in areas with low groundwater. They require a lot of water for their growth. They pull all the water that is available around them causing the lowering of groundwater.

Development in Structural Systems in Postmodernist Period

Evolution of Structural Systems in Postmodernism

Before 20th century, there were three great developments in structural systems.

Bulk Active structure is classified as followed:

  1. Post and lintel
  2. Arch system

Dome and vault construction (either in the form of bulk, employing plastic materials i.e. concrete, hardening into a homogeneous mass or the thrust type, in which the loads are received and counterbalanced at definite points; steel-glass skeleton system.


St. Peter's Dome
St. Peter's Dome


After World War II, the analysis of building types provides information behind each of the greater styles. This can easily be understood that it was not merely a trend, but a period of serious and required experimentation directed toward answering the needs of a specific way of life. In the era, most of the construction work was dominated by sustainable building design, construction and using materials in ways that minimize toxic production methods and in using natural sunlight for energy and natural air movement and water for cooling, climate, methods of labour, available materials, and economy of means thus impose their dictates.

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Fifa World Cup 2010 Soccer City Stadium, Johannesburg, South Africa

Soccer City Stadium is the largest soccer stadium in South Africa. It is situated near Nasrec in Johannesburg, in South Africa. The stadium is the main venue for the Fifa World Cup 2010 kick-off match. This stadium would also host the finals of Fifa World Cup 2010 and the semi-finals are going to be in other two Soccer stadiums of South Africa namely; Cape Town Soccer Stadium and Moses Mabhida Soccer Stadium. There is one other smaller stadium known as Ellis Park Stadium, but it is mainly used during Rugby matches.

Soccer City 3D View
Soccer City 3D View

Soccer City stadium has a capacity of 94,700 people, which makes it the largest stadium in the whole African Continent. It also has a 2 meter moat to keep fans away from players.

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New Scenario of Building Construction | Technological Advancement

Architecture and Civil Engineering | Technological Advances

Technology has really changed the world. Architecture and Civil Engineering have developed immensely with developing Technology. It’s amazing how the scenario of the world has changed in just a matter of 50 years.

Amazing Video. Must watch. Gives you the feeling of being proud of being an Architect or a Civil Engineer…!

Do you feel proud for being a Civil Engineer or an Architect??

 Just have a look at how construction technology has done wonders in the field of construction. Engineers and Architects have taken the technological advances pretty well.

I have always seen a conflict between Civil Engineers and Architects. Both of them have their own egos and think one is superior than the other.

I am presenting some of the patent dialogues from a Civil Engineer and an Architect…

Civil Engineer: I am the one who makes a structure stand on the ground successfully.

Architect: All you do is put some steel into the design made by ME. So, I am the creator and the entire credit goes to me.

Civil Engineer: Architects are crazy. They just draw lines and make weird shapes and forms and think that it could be brought into reality. Do  they know how much trouble it is to give a structural design for such a building?

Architect: Civil Engineers always keep cribbing about the rights and wrongs. They should learn to respect creativity. They should be able to respect the designer’s ability to design something unusual and exciting. It is so difficult for them to break away from their routine box designs.

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Tips to Building Construction | Repairing an Antique door and a Cracked brick wall

Repairing an Old Rotting Antique Door and Repairing a 14″ crack brick wall | Building Construction

In this article, I have mentioned two cases where the remedy for their repair is briefly explained. This sounds very easy but I am sure it will be of good help to all the Architecture and Civil Engineering students…

How would you restore an old rotting antique door?

The dimensions of the antique door are 7’x4’.

The rotting part of the door is to be cut carefully.

And the cut part of the door is replaced by the similar variety of wood.

After replacing the wood, give a similar finish to the door.

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Tips of Building Construction | Civil Engineering

Method of Luppm Finish and Cleaning of pinhead glass | Building Construction

This is a simple article which deals with two different topics explained in a very brief manner. I hope it will be helpful to the students of architecture and Engineering….

How would you clean a 3mm pinhead glass?

Usually, a chemical called as “aerosols” are used for cleaning 3mm pinhead glass.

The welded design on the pinhead glass can be made plain with the help of some chemical powder and then rubbing the glass with a sandpaper.

How would you luppm finish on an already painted wall?

Oil paint + whiting powder= luppm paste is made.

The paint and plaster of the already painted wall is scraped out.

Then the wall is made rough by chiselling or the wall is brushed by a “wire brush” that makes the wall rough.

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Types of Measurements in Surveying | Civil Engineering

Types of Measurements in Surveying

Surveying is the art of making suitable measurements in horizontal or vertical planes. This is one of the important subjects of civil engineering. Without taking a survey of the plot where the construction is to be carried out, the work cannot begin.

From the above definition, we conclude on two types of measurements in surveying. They are as follows:

  1. Linear measurements
  2. Angular measurements

Now we will go on with the discussion of each of these types of measurements along with their subtypes.

Linear measurements are further classified as follows:

Horizontal Distance

Vertical Distance

Horizontal Distance

A horizontal distance is measured in horizontal plane if a distance is measured along a slope, it is reduced to its horizontal equivalent.

Horizontal Angle
Horizontal Angle

Vertical Distance

A vertical distance is measured along the direction of gravity at that point. The vertical distance are measured to determine difference in elevations in various points.

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