Splitting Plane?

[Waqar Saleem]

concrete in beams have one mode of failure by splitting and splitting is of two type one in the plane of rebars and 2nd in the plane vertical to the rebars, how we can determine that splitting will be in which plane and how can we control them accordingly.

[Badar (BAZ)]

who told you that concrete in beams has one mode of failure (you must have heard terms like crushing , compression, tension, shear, torsion and splitting of bond between concrete and rebar) and what rebars are you referring to. please explain. Your question is all over.

[Waqar Saleem]

@baz sir i mean one mode of failure out these all which you have mentioned i studied in twelfth edition Nilson that is 2nd example in chapter dealing bond and anchorage i guess it is 5th chapter,there he writes in the notes that top cover had controlled so the splitting will be in vertical plane b4 he mentioned two planes of splitting one is horizontal to bars plane and 2nd vertical to it i couldn't get what is the criteria of checking that splitting will be in vertical plane or in horizontal plane i didn't have the book with me i'd try make a ref n load it later.

thanx for your response

[Badar (BAZ)]

I don't know that anybody would have done the research in that much detail,I am talking about reason for concrete splitting in horizontal or vertical direction, because we dont need to get into this detail. Important thing is to insure that bond is there between concrete and rebar.

Few things that can be done during construction are compaction to avoid segregation, making sure that rebar is deformed, development length of rebar is provided according to drawings, spacing of transverse rebars and concrete cover is according to drawings.

[Waqar Saleem]

Thank you Mr.Baz , sir if all other factors of failure are controlled then splitting can be controlled by providing sufficient concrete around the long. rebar so that the tensile stress in long. rebars is sufficiently distributed in the adjacent concrete when rebars are too close mean there spacing is less stress in two adjacent rebars will overlap in the surrounding concrete and this will lead to the splitting of concrete in the plane of rebars mean horizontal plane also this type of splitting occurs when side cover is not sufficient,2ndly if the outer cover is not sufficient splitting will be in vertical plane. sir during construction the cares you have mentioned can be assured but if the factors above i mentioned are not checked b4 preparing drawings that wud have nothing to do with the efficiency of the construction.

[Ayesha]

Thank you Mr.Baz , sir if all other factors of failure are controlled then splitting can be controlled by providing sufficient concrete around the long. rebar so that the tensile stress in long. rebars is sufficiently distributed in the adjacent concrete when rebars are too close mean there spacing is less stress in two adjacent rebars will overlap in the surrounding concrete and this will lead to the splitting of concrete in the plane of rebars mean horizontal plane also this type of splitting occurs when side cover is not sufficient,2ndly if the outer cover is not sufficient splitting will be in vertical plane. sir during construction the cares you have mentioned can be assured but if the factors above i mentioned are not checked b4 preparing drawings that wud have nothing to do with the efficiency of the construction.

Good chat. I can give you a very good suggestion. Dont read Nilson. I am saying that because, everyone in Pakistan refers to Nilson. There are other text books far much better than nilson. Do your search.

[Waqar Saleem]

two of them i know and i have are J.G. Macgragor and Macromic these are nice books and truely better than nilson

[Yasir Saleem]

Thank you Mr.Baz , sir if all other factors of failure are controlled then splitting can be controlled by providing sufficient concrete around the long. rebar so that the tensile stress in long. rebars is sufficiently distributed in the adjacent concrete when rebars are too close mean there spacing is less stress in two adjacent rebars will overlap in the surrounding concrete and this will lead to the splitting of concrete in the plane of rebars mean horizontal plane also this type of splitting occurs when side cover is not sufficient,2ndly if the outer cover is not sufficient splitting will be in vertical plane. sir during construction the cares you have mentioned can be assured but if the factors above i mentioned are not checked b4 preparing drawings that wud have nothing to do with the efficiency of the construction.

Waqar your discussion seems very appealing but i have a query ,e.g what kind of loading will be in that case where horizontal splitting is occurring? Because that means you are pushing the bars from both sides is it like that?

[Waqar Saleem]

Thank you Nustian371, sir loading is that of on the beam transverse to longitudinal bars as in usual case of any simple beam when there is no sufficent concrete around the bars i.e c/c spacing b/w two bars is not sufficent the stresses in bars will overlap and generate the cracks in concrete which would be in horizontal plane