Friday

Construction Estimation in Civil Engineering

https://learnandearnd5.blogspot.com/2017/09/construction-estimation-in-civil.html
Construction Estimation in Civil Engineering
The civil engineering project planning and their implementation will ask for estimation for quantities and costs in order to meet the objective of the project.  The cost of the project is estimated by the construction project manager.

Monday

Concrete Mix Design Methods - Methods Used Around World

Concrete was the structural material that was adopted during 19 century. The only criterion that was focused in order to perform the mix proportioning was the compressive strength. Better the compaction and more the cement, better is the strength. 



Some of the early methods that were used for mix design of concrete was based on maximum density and minimum voids. They are mentioned:


Early Methods of Concrete Mix Design

Early methods of Mix design used for concrete mix design are:
  1. Arbitrary Method
  2. Minimum Voids Method
  3. Fuller's Maximum Density Method
  4. Talbot - Richart Method
  5. Fineness Modulus Method


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Recent Methods of Concrete Mix Design

The practice of using early methods made the researched to find out the influence of different parameters that resulted in the development new economical and qualitative methods. Present methods of concrete mix design used around the world are based on the empirical relationships, graphs, charts and from experimental investigations.



Most of the methods used presently will follow the basic principles, but the minor difference exists. Common Concrete mix design methods in vogue are:
  1. ACI Method
  2. USBR Practice
  3. Road Note No.4 Method
  4. British Method
  5. Indian Standard Method


Sunday

What is Structural Equilibrium? | Translational & Rotational equilibrium

Equilibrium can be defined as a state of balance achieved by a structure or a state of rest occurred when all the forces are equal and opposite to each other.


What is Structural Equilibrium


In Structural analysis and structural design, we focus more on the magnitude, direction and the point of application of the forces as well as the resultant forces in order to ensure the state of equilibrium. 


Fig.1: (a)  The resultant force obtained after resolving must be provided with a reaction equal and opposite for maintaining the equilibrium (b) The moment at the cantilever support is the reaction formed that is equal and opposite to the force formed due to the point load at the end of the beam.


In more easy words, a structural element will be in equilibrium when it react with an equal and opposite force to that applied on it.

Conditions of Equilibrium


For a rigid body to be in equilibrium, two conditions are:

  1. The vector sum of all the forces must be equal to zero. This will ensure translational equilibrium
  2. Next, the algebraic sum of all the moments of forces about any point must be equal to zero. This will ensure rotational equilibrium

Newton's Third Law of Action and Equilibrium



As per Newton's third law of motion, for every action there is an equal and opposite reaction along the same line of action as the original force. This is explained in detail in the below figure-2.

What is Structural Equilibrium? | Translational & Rotational equilibrium
Fig.2


Every element part of a structural system will have reactions that will contribute to the equilibrium of the whole system.

Reinforcement Details of Sloped Concrete Roof


The reinforcement detail of a sloped  concrete roof that is supported by a beam of cross section 
250 x 500mm is given below. The thickness of the concrete roof used in 200mm. The overhanging distance of the roof is equal to 60cm. 




Fig.1: Structural Details of a Reinforced Concrete Sloped Roof



The slab is provided with bottom longitudinal reinforcement and top reinforcement as shown in figure -1above. 

Thursday

Spalling of Concrete | How to Fix Spalling in Concrete??

The spalling of concrete is a deterioration seen in structures as a result of advanced corrosion of reinforcement. The stages of spalling of concrete will start with the growth of rust, then cracks and finally push off the part of the concrete cover. 

Cracks in Plaster/Masonry Walls - Causes and Repair

Cracking is a failure that occurs most often in structures. In order to treat the crack, one must know the causes of stresses that have resulted in the formation of cracks. An estimation of these stresses before the construction will help in bringing designs that will have the provision to anticipate for movements that are the reason for cracks. The occurrence of cracks may be in different ways but certain typical modes and characteristics exist for these. The cause of cracks can be clearly understood from the type and the magnitude of the cracking.

Wednesday

Relationship between Porosity & Strength of Concrete


Porosity can be defined as the total volume of the overall volume of the pores larger than the gel pores, expressed as a percentage of the overall volume of the cement paste. The effects of pores smaller than 20mm in diameter were found to be negligible.



Top 15 Factors Affecting Strength of Concrete


The factors affecting the strength of concrete are mentioned below. These factors can be either dependent or independent of each other when comes to the concrete strength. Most of the factors are interrelated in certain means. The primary factor that has a higher influence on the strength of the concrete is the mix design factors. Each of them is mentioned and explained in detail one by one.

Monday

What is Flexural Member?

What is a Flexural Member?


A member of a structure that is subjected to both tension and compression within its depth can be called as a flexural member. As per American Concrete Institute, the following definitions for flexural members are given:



Sunday

What is PERT?? - Advantages & Disadvantages



What is PERT


PERT is Program Evaluation and Review Technique that is used in construction and project management field. This is a project network analysis technique that is used to undergo planning and controlling of the projects. 


The PERT technique focuses on the time and the cost each activity takes. This will hence influence the resultant time and the cost required for the completion of the entire project. This network analysis technique helps to understand the performance of the work throughout the course of the project.

Fig.1: A PERT Network; tE = estimated time for each activity shown on each activity row


PERT is an event oriented project scheduling technique. This method of networking will not show any kind of interdependencies between the events mentioned in the network. The network represents a combination of the event. An event is represented in terms of time and resources that are required for the completion of that event. The PERT network does not have a historic chain as in the case of Critical path method (CPM). 


Note: The PERT technique is more applicable to the projects that are newly faced, where most of the events are employed the first time or by means of a new technique. This is applied on projects that have no repetitive nature.


The PERT technique possess many advantages that facilitate the project team and many disadvantages that have to be taken care by the project managers. The pros and cons of PERT are mentioned below.


Advantages of PERT


The advantages of PERT are mentioned below:

  1. Planning For Large Projects
  2. Visibility of Critical Path
  3. Analysis of Activities
  4. Coordinating Ability
  5. The What - if -Analysis

Planning For Large Projects: The scheduling of project activities is done easily with the help of PERT system by the project manager. This technique is more active in large sophisticated project works. As PERT is event oriented programming technique, three elements are necessary to define an event. They are:

  1. What is the time required to perform the event?
  2. What comes after the event?
  3. What is coming before the event?
The answers to the above question make the scheduling easier and clear.


Visibility of Critical Path: The PERT method will show the critical path in a well-defined manner. The critical path is the path with activities that cannot be delayed under any circumstances. A proper knowledge about the stack values with limited conditions of dependencies will help the project manager to bring fast and quality decisions that will favor the project performance.

Analysis of Activity: The activity and the events are analyzed from the PERT networks. These are analyzed independently as well as in combination. This will give a picture about the likely completion of the project and the budget.

Coordination: The various departments of the construction organization will deliver data for the PERT activities. A good integration is developed between all the departments which will help in improving the planning and the decision-making capabilities of the project team. The combination of qualitative and quantitative values from a large amount of data will help in improving the coordination of the project activities. This will also improve the communication between various departments of the organization.

What - if -Analysis: The possibilities and the various level of uncertainties can be studied from the project activities by properly analyzing the critical path. This type of analysis is called as what-if-analysis. For this various sets of permutation and combination is conducted. Among them, the most suitable combination is taken into consideration. This set chosen will be the one with minimum cost, economy and best result. This analysis helps to identify the risk associated with any activities.


Disadvantages of PERT

Various Demerits of PERT are mentioned below:

  1. Time Focused Method
  2. Subjective Analysis
  3. Inaccuracy due to Prediction
  4. Expensive 
  5. Other Issues
Time Focused Method: The method of PERT is a time oriented method, where the time required to complete the respective activity is of higher importance. Hence the time determination of each activity and its allocation is very much necessary. This is done based on an assumption and within this time the work will be completed. If this is not the case issues will arise.

Subjective Analysis: The activities for a project is identified based on the data available. This is difficult in case of PERT as these are mostly applied for a project that is newly conducted or those without repetitive nature. The project dealt by PERT will be a fresh project data that make the collection of information to be subjective in nature. This will bring less accuracy on the time and the estimated time.
         There are chances to have inaccuracy and bias in the sources of data. This makes it unreliable. As this is not repetitive in nature, there is no sense in bringing the records from the past historical data.

Prediction Inaccuracy: As there is not past records or assistance to bring an outline for the project, predictions take their role. The overall project may move to total loss if the predictions and the decisions are inaccurate. No trial and error method can be employed.

Expensive: As this method is carried out based on predictions in overall, they find too expensive in terms of methods employed, the time consumed and the resources used.

Other Issues: This method is highly labor intensive in nature. As there are chances of increase in project activities large and complicated networks are developed as many task dependencies come into existence. If two activities share common resources, this technique won;t find very apt for the project. 

No: 152

Tuesday

What is Concrete Flatwork??


Concrete flatwork is a common choice for the installation of garages and basements or any other flat surfaces. This is less expensive when compared with the stone or the brick masonry. This method will provide a variety of options and have good expertise in finishing, thus make the surface aesthetically pleasing. 

Fig.1.Concrete Flatwork with Patterns

Friday

Load Action on Columns | Column Load Status -



Consider a perfectly straight vertical column subjected to an axial load. With the increase in the axial load, the column goes through three conditions



· Stable equilibrium
· Neutral equilibrium
· Instability

Role Of Building Architecture Towards Seismic Action

Building Architecture Towards Seismic Action


The response towards an earthquake force is different for a different building. Some building may stand still for an earthquake but another won't stays stable for the same earthquake. In addition to the way the earthquake force is carried to the region ,it also depends on the


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This is a center to bring up and collect all bits of knowledge and technologies flourished and flourishing to reach out for those who wish to acquire knowledge in a broader way. I am a structural engineer by profession and would like to share all information I have acquired all these years till date. This site also aims in researching new topics, works on your questionnaires and fill it up with good facts and information.

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