What is Bond, Flexural , Anchorage Bond and Development Length - civilengineer friend

SSC JE 2019 QUESTIONS AND ANSWERS

civilengineer friend

Civilengineer friend no one website Civil engineering Subjects tutorial Learn Civil Engineering online Building construction Building material Bricks Cement Concrete technology Irrigation engineering R.C.C. Structure design Limit State Method Working Stress method Strength of material SFD and BMD Surveying Theory of structure Architects I Engineers I Developer Assure Quality With Excellence

test banner

Tuesday 18 June 2019

What is Bond, Flexural , Anchorage Bond and Development Length

What is Bond, Flexural , Anchorage Bond and Development Length

development length,what is development length,what is lap length,what is bond and development length?,difference between lap length and development length,what is lap length and development length,what is lap length development length and anchorage length?,lap length vs development length,what is steel development length,what is anchorage length,lap length,importance of bond and anchorage length

Bond:-
The most important assumption made in the theory of RCC is that there is a perfect bond between the concrete and steel. Perfect bond in the sense the bond should act in such a way that there is no slip b/w steel and concrete.
This bond helps in transferring force from steel to concrete and concrete to steel.



Bond stress:
The stress which is acting on the outer interface of steel to the surrounding concrete is called bond stress. This stress helps in keeping bond between  reinforcement and concrete together. Bond stress resists any force that tries to pull out the rods from the concrete.
When you try to pull out the reinforcement bar from hardened concrete, then this Bond stress resists the bar to come out.
By the way different grades of concrete has different bond stress.
well, these bonds are classified into two types:-
  1. Anchorage bond (Development length)
  2. Flexular bond.
Anchorage bond:- 
This bond is seen  when a bar carrying certain force is removed. In such cases,  it is necessary to transfer this force in the bar to the surrounding concrete over a certain length.
This length of bar  required to transfer the force in the bar to the surrounding concrete through bond is called “Development length (D.L.)” 
Development length

Development length (DL) is determined by performing Pull out Test.It is clear from the above image, that reinforcing bar is embedded in concrete and subjected to a pull T
T = Design Stress x area of bar = 0.87 Fy x (Pi/4) x d2
d= Dia of bar
This force must be transferred from steel to concrete through bond acting over the interface (perimeter) of the bar over a length (D.L.)
If Tbd = Avg Design bond stress
Then Ultimate Bond force = Pull out force
Tbd (Pi x d) x D.L. = 0.87 Fy [(Pi/4 x d^2)]
D.L = [0.87 x Fy x d] / [4 Tbd] 
hence all bars should extend to a distance of (DL) beyond the section where they are required to take full design force.
it is not possible to provide straight bars at all the times due to lack of space at supports. In such scenarios we provide them as hooks and bends.
The anchorage value (hook length) = 16d
The anchorage value (Bend length) =4d (45degree angle)


What is the development length formula?
Formula for development length(Ld) is - Ld= 0.87 X grade of steel X Dia of bar / 4 X bond stress of concrete . Value of Bond stress can be increased by 60% when high yield strength deformed( HYSD) bars are used. It can be further increased by 25% when we calculate development length for bars in compression.
What is difference between Anchorage length and development length?
Definition – As the name suggest, lap length is provided for overlapping two rebars in order to safely transfer the load from one bar to another bar. ... Definition –Development Length is provided to transfer the load from steel to concrete.Development Length is also known as anchorage length.

Read more :

 Development Length Calculation as per Indian Code

 Must-Know Points to Check on a Cement Bag Before Buying It

 All Types of Cement in Construction 

How to calculate cement, sand quantity for Plastering

No comments:

Post a Comment

If you are getting more information from civilengineerfriend page please give your comments. Share the page information in your whatsapp group. Subscribe our page to get more information.