written 5.8 years ago by |
Given
load=250KN
Design bolted connection
1) Shearing strength of bolt $\frac{fub\times(nn.Anb)}{\sqrt{3}.\gamma mb}$
=$\frac{400\times(1\times245)}{\sqrt{3}\times1.25}$
Vdsb=45.26KN
strength of bolt=45.26KN
No of bolt =$\frac{250}{45.26}=5.52\sim$7 Nos
Tdg=$\frac{Ag.\times fy}{\gamma mo}$
Ag=$\frac{Tdg\times \gamma mo}{fy}$
=$\frac{250\times1.1}{250}$
=1100mm$^{2}$
provide 90$\times60\times10mm$ Aprov=1401mm$^{2}$
e=1.7$\times$22=40mm
e=2.5$\times$d=2.5$\times$20=50mm
Assume gauge distance g=50mm
Tdn=$0.9\times Anc\times\frac{fu}{\gamma ml}+BAgo\frac{fy}{\gamma mo}$
or
Tdn=$\gamma\times An\frac{fu}{\gamma m1}$
Anc=$(90-\frac{10}{2})\times10-(22\times10)$
=630mm$^{2}$
Ago=$(60-\frac{10}{2})\times10=550mm^{2}$
An$\gt $Ag required
Tdn=08$\times$1180$\times\frac{410}{1.25}$=309.63KN
block shear
Tdb$_{1}=\frac{Avg.fu}{\sqrt{3}.\gamma m0}+\frac{0.9,Afn.fu}{\gamma m1}$
Tdb$_{2}=\frac{0.9\times Avn.fu}{\sqrt{3}.\gamma m1}+\frac{Afg.fy}{\gamma mo}$
Afg=40$\times$10=400mm$^{2}$
Afn=$(40-\frac{1}{2}\times22)\times10=290mm^{2}$
Tdb$_{1}=\frac{3400\times250}{\sqrt{3}\times1.1}+0.9\times290\times\frac{410}{1.25}$
Tdb$_{1}$=531.74KN
Tdb$_{2}=\frac{0.9 \times 1970\times410}{\sqrt{3}\times1.25}+\frac{400\times250}{1.1}$
Tdb$_{2}=426.66\times10^{3}$
Tdg=$\frac{Ag\times fy}{\gamma mo}$
=$\frac{1401\times250}{1.1}$
Tdg=318.40KN
Design strength of angle =309.63KN
(least of 318.40,426.66)
Total tensile strength of angle 309.63$\gt$250KN
Hence design is safe