Saddle calculation as per LP Zick Method (div 1)

[susanbhj]

While going through compress calculation, I found some doubts while taking the loads during calculation.

1) Bending Moment calculation at the saddle
Mq = w*(2*H*Al / 3 + Al^2 / 2 - (R^2 - H^2) / 4)
Where, w=Wt/(L+4H/3)
As per compresses calculation, Wt is taking as total operating weight. As my concern is that it is missing the additional load due to either wind/seismic during moment calculation that means it is neglecting the stress due to wind/seismic at the saddle support. Am I correct?

2) Shear stress Calculation:
Same problem I found calculating shear stress.
Qshear = Q - w*(a + 2*H / 3)
Where, Q=total weight +seismic/wind load
W=unit operating weight per effective length.
Am I right guy?

 

[jharris3]

The calculation of 'w' and 'Q' include the seismic or wind loadings.

Compare the numbers in the calculation rather than just looking at the equations.

Notice that Q involves Ql and Qt; both of those use the wind shear V and the largest of the two is added to W.

w is harder to show but it works out.

 

[susanbhj]

if u see my attached file with additional wind load calculation u will see that

Q = Weight on saddle + larger of Qt or Ql
Q = W + Qt = 79,124.98 + 5,697.82 = 84,822.79 N

w = Wt / Le = 157,271.34*10 / 6,648 = 236.57 N/cm

where total operating weight= wt on saddles
=(7968.7+8068.5)*9.80665=157271.2N

During calculation of Bending Moment calculation at the saddle
Mq = w*(2*H*Al / 3 + Al^2 / 2 - (R^2 - H^2) / 4)

don't u think it miss the additional load Qt (5697.82N) while calculating Mq? It's clear.

u can check in ur compress model also with additional loads(seismic or wind).