How to know the size (dimensions) of transverse links to be provided for concrete walls - Eurocode 2 2

[Pretty Girl7]

For the concrete walls, the following is mentioned in the Eurocode 2. And I noticed all the spacings are mentioned and also has mentioned to provide the transverse links in the form of "links" and r/f thicknesses also have been mentioned. And it has further mentioned to provide 4 links per metre square in the clause. 9.6.4 (2).

My question is, how do we know the exact dimensions of the transverse links to be provided for the concrete walls? The links can be in various types in dimensions as shown below.

 

[centondollar]

That is up to the designer. In principle, any amount and configuration which activates a strut-and-tie mechanism is acceptable. On the other hand, the purpose of shear links is also to tie reinforcement and confine the concrete, increasing the ultimate (crushing) strength of the concrete and in that way increasing the ultimate strength of the cross-section. For confinement, the "link type 3" is least favorable; link type 1 or two link type 2-configurations are better choices.

 

[HTURKAK]

Provision for links;

-When the compression reinforcement in the wall exceeds 0.02Ac, links must be provided in accordance with the rules for columns in clause 9.5.3..
- The diameter of the transverse reinforcement should not be less than 6 mm or one-quarter of the diameter of the largest longitudinal bar whichever is greater.

-Where the main reinforcement is placed nearest to the wall faces, transverse reinforcement should be provided in the form of links ( cross ties ) with 4 per m2 of the wall area. ( Literally spaced horizontally and vertically not more than 50 cm )

I hope this respond answers to your question








Tim was so learned that he could name a
horse in nine languages: so ignorant that he bought a cow to ride on.
(BENJAMIN FRANKLIN )

 

[Pretty Girl7]

That is up to the designer. In principle, any amount and configuration which activates a strut-and-tie mechanism is acceptable. On the other hand, the purpose of shear links is also to tie reinforcement and confine the concrete, increasing the ultimate (crushing) strength of the concrete and in that way increasing the ultimate strength of the cross-section. For confinement, the "link type 3" is least favorable; link type 1 or two link type 2-configurations are better choices.

Thanks for the reply. I will look more into strut-tie method.

 

[Pretty Girl7]

Provision for links;

-When the compression reinforcement in the wall exceeds 0.02Ac, links must be provided in accordance with the rules for columns in clause 9.5.3..
- The diameter of the transverse reinforcement should not be less than 6 mm or one-quarter of the diameter of the largest longitudinal bar whichever is greater.

-Where the main reinforcement is placed nearest to the wall faces, transverse reinforcement should be provided in the form of links ( cross ties ) with 4 per m2 of the wall area. ( Literally spaced horizontally and vertically not more than 50 cm )

I hope this respond answers to your question

If it should be spaced not more than 50 cm, then the question solves right there. Can I please know where did you get that "50 cm" limit? I didn't notice it in the Eurocode 2.
Edit: now I get it, you just divided the 1m2 into four areas. Took a couple of minutes to figure out. So, I don't have to go through the strut-tie method then.

So the code is asking to provide cross-ties, not the closed-ties like above?. So, should it be like following tie? (the reason I'm asking this is, if I use "closed-ties" x 4 units, the r/f area doubles than "cross-ties")
Does the code state to use "cross-ties" in-spite of "closed-ties"?

 

[Pretty Girl7]

can anyone please confirm if it should be a "closed-link" or a "cross-tie"? the reason I'm asking this is, if I use "closed-ties" x 4 units, the r/f area doubles than "cross-ties"

 

[HTURKAK]

I just saw your last comment..

My points as per my interpretation are ;

- If the compression reinforcement in the wall exceeds 0.02Ac, links must be provided through the wall thickness in accordance with the rules for columns in clause 9.5.3 .( and clause 9.5.3 is for column reinf. and covers containment of compression reinforcement with closed links)

- In case of seismic design with ductile wall section, the boundaries shall be confined with closed links ,

- If the compression reinforcement in the wall DOES NOT EEXCEED 0.02Ac , the wall could be reinforced assuming that only end zones resist moment,provide both ends with U shape links ..

- Provide cross-ties for the mid section btw the boundary elements , end zones..

The following is snap from Manual for Detailing Reinforced Concrete Structures to EC2 ( by JOSE CALAVERA)

...and Ductile wall (from FARDIS)

Tim was so learned that he could name a
horse in nine languages: so ignorant that he bought a cow to ride on.
(BENJAMIN FRANKLIN )