written 5.8 years ago by |
the bolts are 20mm $\phi$ m and 4.6 grade
Step I
list bolt value=$\frac{fub\times Anb\times hn}{\sqrt{3}ymb}$
=$\frac{400\times245\times 1}{\sqrt{3}\times 1.25}$
Vdsb=45.26kN
Step II
dirct shera force per bolt=$\frac{w}{6}$ in horizontal direction
direct shear force per bolt=$\frac{2}{6}$in vertical direction
F1=$\sqrt{(\frac{w}{6})^{2}+(\frac{w}{6})^{2}}$=0.236w
Step III
force in bolt due to tortion
F2=$\frac{\sum(w.e)\gamma n}{\sum \gamma ^{2}}$
$\sum $we=w(700)+w(80)=780w
$\gamma n=\sqrt{80^{2}+80^{2}}$=113.13
$\gamma ^{2}=6(80)^{2}+4(80)^{2}$=64000
F2=$\frac{780w\times113.13}{64000}$
F2=1.37w
Step V
Resultant flow equation
R=F1+F2
45.26=0.236w+1.378w
w=28.02kN
Step VI
safe working load=$\frac{w}{1.5}$
=$\frac{28.02}{1.5}$
=18.68kN
Type II
bolt are sub to direct shera and bending tention
Step I-
Find bolt value
Step II -
No. of bolts required=$\sqrt{\frac{6m}{n\times p\times Bolt \ value}}$
M=P.e
P=eccentric load
E=eccentric distance
n=no.of rows
P=Pitch distance
Bv=list bolt value
Step III -- Total height of plate
H=2e+$\sum$P(pitch distance)
Step IV- Interaction equation
$(\frac{Vsb}{Vdb})^{2}+(\frac{Tb}{Tdb})^{2}$
Step--V direct shear=$\frac{Reaction}{No.of \ bolt}$
max Tensile force in critical bolt=$\frac{m\times yn}{\sum y^{2}}$
$m^{'}=\frac{m}{l+(\frac{2h}{2l}\times \frac{\sum y}{\sum y^{2}})}$
h=H-e