Civil Engineering/shear force factor 2
QUESTION: hello ENG.Babak Esmailzadeh Hakimi
in british code BS8110 ,the design effective shear is calculated from Veff = (1.25 or 1.15 or 1.4 )* Vt
the factors (1.25 , 1.15 , 1.4) depend on the case of column ( internal / at corner / at edge )
my question is :
Q1: in the attached image , what is the range of values a,b to consider the column as internal or corner or edge ?? should we compare a,b with effective depth d ?
to clarify my question , for example :if a=0.25 m , b = 1 m and the d=0.2 m do we consider this column as internal or corner or edge ?
ANSWER: Dear Hassan
This is for punching shear provision. You should compare the sides margin with d/2 ( d is more reliable ) . You should be certain that with a good accuracy the real punching area matches with the calculation assumption. The case you notes can be assumed to be the the case with 1.4.
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QUESTION: Thank you very much
one thing more please :
you told me that i should to compare the sides margin with d/2 ( d is more reliable ) and I should be certain that the real punching area matches with the calculation assumption .
as per Bs 8110 , the critical punching perimeter is at 1.5d from the column faces.
Q: does it mean that I should compare with 1.5d if I use Bs 8110 ?
You must conform with the code you are designing upon. Usually the side or corner columns have moderate axial loads which make the punching matter in corners and sides not worse than the middle cpolumns.
beside this , 1.5 d is a very conservative limit but in the case of non loaded sides it must be strictly fulfilled.