Obviously, it is impossible to use continuous reinforcement concrete bars; thus, several splicing methods are available to tackle the problem. Among them, overlap with tie wire, coupling, and welding methods are the common ones.
The question that has been on my mind is: What is the force transmission mechanism difference between these methods?
In the overlap splicing method, there is inherent space between the center of the bars. It means that there is a discontinuity in force transmission in this method. On the other hand, in mechanical splicing (coupling), the rebars' center is in precisely the same direction. Several tensile tests in this method have shown us that the rupture will never happen in place of the patch (beneath the coupling). While in the overlap splicing method, a fracture could occur anywhere along the rebar.
The question is that, has the force transmission mechanism taken into account for splicing rebars? Or overlap splicing method exists just to keep the rebars in their place for concreting?
Because the mentioned methods are acting quite differently in terms of the force transmission mechanism.
Thank you so much for your attention and participation.
I think international concrete codes take these details into account. But, here we must provide an adequate running length for rebar that no debondind happen! And keeping tension force path as efficient as possible. For interaction zone, the amount of longitudinal reinforcement always doubled and no failure reported for this region in some literature That I read. Thank you that was good question.
Dear Abdullah Sikar Al-Issawi
Thank you for the response.
in the response, you said, "no debonding happen!"
in the overlap splicing method, inherently, there is no bonding!! Two rebars connect with each other side by side with just some tie wire. We can not call some tie wires a bonding! However, there is bonding in the coupling and welding method.
That is exactly why I am wondering how do these methods are the same for all international codes!!
I carried out some tests on tensile failure (as try and error side investigation). No difference recorded between welded bars and those were fastend by steel wires (for 50 cm length and 5 cm tied spacing). You can run it by yourself dear.
Dear Abdullah Sikar Al-Issawi
I would be more than happy if you could provide us the test results you conducted.
I think Codes are looking for the longitude rebars' section area in each section of the concrete elements (column, ..). it seems they don't care about bonding and the force transmission mechanism with rebars.
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