hi sir
i have a problem with shear stress for punching
the problem is
when i read the shear stress in robot give me strange values
i have done manual calcolation punching for internal l column
fc=25 mpa ,fy=420 mpa, cover =25mm, thikness=250mm
c1,c2=50cm
pu=1025 kn
Mux=35kn.m
Muy=35kn.m
--------
b0=2.9
jc=0.0585 m^4
Vu max aplied shear = 1.744 mpa
sir i want to read the Vu from robot how -
see attachments please
Solved! Go to Solution.
Solved by Rafal.Gaweda. Go to Solution.
Hello,
Assuming you have parameter set to middle, the values of shear stress you are seeing are 1.5 x the average shear for a rectangular section, so your 1.744 (average) would show up as 2.62 at the middle of the rectangular cross section and 0 at the upper and lower. Try it on a simple span beam to verify.
Hope this helps a little.
Regards
Chris
thank you chrismcc for help.
Dear sir Rafal
im really confused for reading shear stress in robot
i attach the manaul hand calcolution for punching
and i tryed to take the Reduse forces above the column and wall but still not close to 1.744mpa it was 1.37mpa
see attachment please
thank you sir for reply
sir is this facotre (2/3) i mean working for corner column and edge as well ?
and why you didnt read 3.27 instead of 2.93 ?
i wish to know please
Again thank in advance
egoze
sir is this facotre (2/3) i mean working for corner column and edge as well ?
and why you didnt read 3.27 instead of 2.93 ?
I took middle value
helooo sir
i have done corner column for the same modle ,and i rearange the corner column in slab to conseder it as a corner .as you know sometimes the robot coseder it as an edge column
i have read the stress at the face of column in robot are was 3.86 and 1.5 mpa
the average (as you said )=2.68 mpa
2/3*2.68=1.78mpa
good for maunual calco=1.86 mpa
my question WHEN YOU DO CHECK PUNCHING BY THE PROGRAM
Q(KN) IS VERY VERY LARGE ?????
YOU CAN SEE THE ATTACHMENTS
**************new
hello sir
i have done corner column for the same modle ,and i rearange the corner column in slab to conseder it as a corner .as you know sometimes the robot coseder it as an edge column
i have read the stress at the face of column in robot are was 3.86 and 2.56 mpa
the average (as you said )=3.21 mpa
2/3*3.21=2.14mpa
for maunual calco
force=205 kn
m1 =105kn.m
m2=86kn.m
b1=b2=c1+d/2=0.5+0.217/2=0.6085
bo=1.217
Jc=0.016
Vu=0.776+0.759+0.622
Vu= 2.159mpa max stress
my question WHEN YOU DO CHECK PUNCHING BY THE PROGRAM
Q(KN) IS VERY VERY LARGE ????? what is the furmula of Q(KN)
have a look for new pic please
egoze perhaps this page will help and also download the verification manual for EU codes from here (dropbox). (If the downloaded file isn't shown properly just add-type .pdf after the name of the file)
Good link.
In short : moments are also considered in punching check ; Q and Qadm are calculated reducing set of forces to axial force only (giving the same punching like initial axial force and moments)
Thank you sir
a small point can i find this (data used for calculations in Robot) as you did
for anther columns
how can i got this data used for calcolation