Posts Tagged Design of RCC structures
Bending Moment and Fixed Moment Calculations
Posted by BenzuJK in Building Construction on December 26, 2011
Bending Moment and Shear Force diagrams
What is Bending Moment?
The element bends when a moment is applied to it. Every structural element has bending moment. Concept of bending moment is very important in the field of engineering especially Civil engineering and Mechanical Engineering.
Unit of measurement: Newton-metres (N-m) or pound-foot or foot-pound (ft.lb)
Bending moment is directly proportional to tensile and compressive stresses. Increase in tensile and compressive stresses results in the increase in the bending moment. These stresses also depend on the second moment of area of the cross section of the element.
What is Shear stress?
Shear stress is defined as the measure of force per unit area. Shear stress occurs in shear plane. There are many planes possible at any point in a structure which can be defined to measure stress.
Stress = Force/Unit area
Example: Bending Moment and Shear Force Calculations
Frame diagrams | Bending moment and shear force calculations
Simply supported bending moment
Mab = wl2/8 = (22×4.14×4.14)/8
= 47.13 KN-m
Mbc = wl2/8 = (22×4.14×4.14)/8
= 47.13 KN-m
Building Materials | Use of Carbon-negative Cement in Building Construction
Posted by BenzuJK in Building Construction on December 13, 2011
Carbon-negative cement | New revolutionary Building material
Carbon-negative cement…?? Sound different, doesn’t it?
Have you ever realized how much carbon is emitted because of using concrete in the construction of buildings, highways, dams, bridges etc?
Well, here’s an answer to that. It is found that out of the 100% carbon dioxide emissions, 5% of the emissions are caused by human activities. Majority of the carbon emission is caused by usage of concrete in the constructions. How? Cement is an indispensible ingredient used for making concrete. Cement is made by baking limestone and clay powders under intense temperatures (high temperature). The intense heat which is required for the production of cement is achieved by burning of fossil fuels which in turn release large amount of carbon dioxide into the atmosphere.
Building Construction | We can just imagine to what extent the carbon dioxide would be released into the atmosphere.
Carbon dioxide is also released when the conversion of limestone takes place in the kilns. This conversion is called “Calcination”. It has been observed that the amount of carbon dioxide emitted during calcination is much higher than that which is released due to burning of fossil fuels.
Recently, a British company called “Novacem” came up with this concept of manufacturing ‘carbon-negative’ cement that absorbs more carbon-dioxide than it emits over its entire life cycle.
Calculations for Overhead Water tank | Building Construction
Posted by BenzuJK in Building Construction on November 6, 2011
Design of Overhead Water Tank | Design of RCC Structures
As per NBC (National Building Code, 2005) standards,
Water required per person per day = 150 litres
Drinking water = 4litres per person per day
Calculation for an overhead water tank for a 3 BHK Villa:
Let us assume the average family size = 5 persons in the house
Water required for daily chores per person per day as per NBC norms;
150 x 5 = 750 litres
Drinking water required:
4 x 5 = 20 litres
Total quantity of water required = 750+20 = 770 litres
Volume of water = 770/1000 = 0.77 cubic metres
Consequences of Wrong Structural Design | RCC Structures
Posted by BenzuJK in Civil Projects on October 29, 2011
A lesson for all the Civil Engineers and Designers to learn
I got a project of designing (Architectural Design) a Hostel in Lucknow, India. The Structural design that is, column positions and wall construction was already done. The client wanted me to design a Hostel keeping the column positions and exterior wall construction intact. I have written this article to address all the Civil engineering students as well as Civil Engineers to avoid making such blunders while they design. Please do read this article because understanding the intensity of the job of a Civil Engineer is must for every student and professional. I guess this realization has been washed away and forgotten in the wave of commercialism.
Hostel Design, Lucknow, India
The client mailed me the layout of the existing construction. After I studied the layout, I figured out that the Column layout was pathetic. I wonder what kind of Civil Engineer must have made the layout or if at all any Civil Engineer has done it.
Errors in Construction
Wrong size of the Columns
The size of the columns was 9”x9” and the building is supposed to be constructed upto G+2 floors which is really disastrous for the structure.
It could lead to structural failure and ultimately structural collapse.
(The duty of the Civil Engineer is to understand and not make such dramatic blunders. The consequences of this kind of structural design could be disastrous.)
Column layout and Exterior wall Construction
9”x9” size columns are only preferred if you were to construct only a ground floor structure using M15 grade concrete. If you are to construct another floor that is (G+1), the minimum size of the column should not be less than 9”x12” using M15 grade concrete.
If the client insists on using smaller columns (9”x9”); in that case, use of M20 grade concrete should be done mandatorily and the construction should not be initiated before the client agrees to do so.
Minimum Standards for Structural Design | RCC Structures
Posted by BenzuJK in Civil Projects on October 9, 2011
Thumb rules for Structural Design | RCC Structures
Design of RCC Structural Components
In this article, we are going to discuss the minimum standards that are to be followed for the design of Structural components of a building such as Columns, beams, slab and foundation. We will also discuss the minimum safe standards for the reinforcing bars that are to be used for the design of the above mentioned Structural Components.
Minimum cross-sectional dimension for a Column: is 9”x9”. But to avoid slenderness ratio problems in multistorey buildings, we prefer a rectangular column design of 9″x12″ which is safer.
Also check out:
Thumb rules for making a Column Layout
Construction on Site | Design of RCC Structures
Minimum RCC beam size: is 9″x9″. But generally, to maintain uniformity and speed of construction, we design all beams of the same size 9″x12″. But 9″x9″ can also be used safely, according to design.
Minimum thickness of RCC slab is 4.5″ because a slab may contain electrical pipes embedded into them which could be 0.5″ or even fatter for internal wiring, which effectively reduces slab depths at certain places, causing cracking, weakening and water leakage during rains. So, a minimum thickness of 4.5″ should be maintained.