July 2017 - CIVIL PRODYOGI

Friday

Classification of Aggregate Based on Texture

July 28, 2017

Aggregate Classification Based on Texture




Based on texture, aggregates can be classified into

  1. Smooth Surface Texture Aggregate
  2. Rough Surface Texture Aggregate
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Tuesday

Internal Redundancy and External Redundancy

July 25, 2017 0

Fig.1 Continuous Indeterminate Bridge Structures-Girders

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Construction Aggregate - Classification Based on Density of Aggregate

July 25, 2017

Fig.1.Construction Aggregate
The Aggregates can be classified based on the density of aggregates as

  1. Normal Weight Aggregate
  2. Heavy Weight Aggregate
  3. Lightweight Aggregate
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Wednesday

Bar Bending Schedule of an R.C.C Beam

July 19, 2017
The preparation of bar bending schedule of an R.C.C beam requires proper understanding of the design and the detailing of the structural member. The calculations involved in the preparation of an R.C.C beam is explained step by step in this article.



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Tuesday

Bar Bending Schedules in Construction

July 18, 2017

In reinforcement detailing of concrete, it is very important to keep an order in which a bar is fixed. The bars that are used are numbered appropriately as per the placement in the drawings and the schedules kept.



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Sunday

What is Free Body Diagram (FBD) in Structural Analysis ??

July 16, 2017

Fig.1.Free Body Diagram of A Cable Joint

Free body diagram is one of the main aid used for solving static problem in the static analysis of structures.



Free Body Diagram of Structural Elements


The free body diagram is method that can be used in modelling a structure conveniently. FBD in more precise way is a method that we use to conceptualise a structure or its respective elements so that easy analysis of the same can be carried out.

The free body diagram can be defined as a graphical, symbolic and a dematerialised representation of a structure or its elements. This conversion will remove all the connecting pieces.

While drawing a free body diagram, all the physical attributes that are on the structures are removed and symbolised conceptually. 

Features of Free Body Diagram

  1. A simple single line will be used to represent a body or a segment
  2. Connection will be represented by distinct properties.The junction will be conceptualised to a set of forces and moments. These forces are reactions at the connection. 
  3. When comes to nodes, there are internal forces. These are represented by means of external forces. This will include the influence from all the members that is connected to that node.

Consider the figure-2 below. The features explained below can be properly explained with the help of this figure. This is a street lamp. The different stages that are used to evolve the free body diagram of the street lamp is explained below. 





Fig.2.Free Body Diagram of a Street Lamp
1. Initially, the whole system is dematerialised. Here, the lamp is dematerialised into a body that is weighing say 30#. The weight is acting in the direction of gravity from the centre of the body(downwards). Hence a straight line arrow heading downwards is drawn from the centre of the lamp. The system have lamp as the only element, whose weight is known.

2. Next we need to find other forces that will keep this lamp in equilibrium. For this we look at the left end fixed support. Now we identify the forces and moments that will be generated in a fixed support. The fixed support will have a moment, vertical reaction and Horizontal reaction.As here, there is no other horizontal force, the horizontal reaction can be neglected. Hence at the left end fixed support , we have a vertical reaction and a moment.
More about Different Supports & Reaction- Read the article: 
Supports and Reactions in Structural Analysis
3. Next the span distance can be obtained from which the final free body diagram can be drawn.

All those necessary elements of force that is essential to analyse or solve a force system will be included in the free body diagram (FBD).

FBD is not found essential in simple problems. But, when it comes to complex analysis situations, FBD methods is increasingly utilised.

More examples of conversion of load systems in to free body diagrams are explained in the examples below.

Example 1: A Beam Fixed at one end and Free at other end



Fig.3.Free Body Diagram of a Cantilever Beam with a Point load at the end




Example 2: Three Different Structural Systems with same loading and support



Fig.4. Three Different Structural Systems in Real Arrangement
The free body diagram for the above structural systems can be drawn as shown in figure-5 below. Here you can see that the internal structural elements have been removed in the FBD diagram. This is because, the internal arrangement have no influence in determining the support reactions. 

Fig.5.Free Body Diagram of Figure-4


And if the loading geometrics and the supports are the same, the external reaction will also remain the same.







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Tuesday

Different Types of Paints Used in Construction

July 11, 2017


Paint is a fluid material that has the ability to spread on a solid surface. This material on drying will form a film. The paint is applied in different layers over the surface called as the primary coat called as a first coat, second, second loaf etc.

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Thursday

Building Structural Systems

July 06, 2017
Any structure under consideration is made of both the structural elements and non-structural elements. The structural elements are elements that are load carrying units. For.example columns and beams. Non-structural elements are those that do have a major role in load carrying, these involve false ceilings, partitions, doors etc.


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