Topic Options
#40733 - 02/07/11 02:07 AM Moments and Shears in legs and saddles
MARVIC2110 Offline
Member

Registered: 02/07/11
Posts: 5
Loc: Madrid
Hi,

I have a doubt, PV Elite not calculed the shear and moment produced by wind and earthquake in vessels with legs or saddles.
In case of horizontal vessels, Pv Elite calcule the maximum shears and moments, but he not specify the condition.

Please somebody can to clarify me these points.

Thanks in advance, regards.

Top
#40756 - 02/07/11 08:06 AM Re: Moments and Shears in legs and saddles [Re: MARVIC2110]
MARVIC2110 Offline
Member

Registered: 02/07/11
Posts: 5
Loc: Madrid
Sorry,
I find the shears and the moments for the legs, but not for the saddles. How can find this values for wind and earthquake in baseplate of saddles?

Thanks for your kindly cooperation.
Regards,

Top
#40827 - 02/09/11 05:48 AM Re: Moments and Shears in legs and saddles [Re: MARVIC2110]
ARG Offline
Member

Registered: 10/27/09
Posts: 11
Loc: L&T,Gujarat , India
See the calculation of saddles, you will find the shear & moments.
_________________________
Ankur Gupta
L&T C

Top
#40876 - 02/10/11 01:49 AM Re: Moments and Shears in legs and saddles [Re: ARG]
MARVIC2110 Offline
Member

Registered: 02/07/11
Posts: 5
Loc: Madrid
Exactely, but they not especify if the shears are for the wind case o earthquake case. I need to know these cases for trasmit the loads to civil department.

An example:
Intermediate Results: Saddle Reaction Q due to Wind or Seismic

Saddle Reaction Force due to Wind Ft [Fwt]:
= Ftr * ( Ft/Num of Saddles + Z Force Load ) * B / E
= 3.00 * ( 4392.0 /2 + 0 ) * 1590.0000 / 2443.9238
= 4286.1 Kg

Saddle Reaction Force due to Wind Fl or Friction [Fwl]:
= Max( Fl, Friction Load, Sum of X Forces) * B / Ls
= Max( 793.70 , 5969.35 , 0 ) * 1590.0000 / 5350.0005
= 1774.1 Kg

Saddle Reaction Force due to Earthquake Fl or Friction [Fsl]:
= Max( Fl, Friction Force, Sum of X Forces ) * B / Ls
= Max( 26212.75 , 5969.35 , 0 ) * 1590.0000 / 5350.0005
= 7790.3 Kg

Saddle Reaction Force due to Earthquake Ft [Fst]:
= Ftr * ( Ft/Num of Saddles + Z Force Load ) * B / E
= 3.00 * ( 0 /2 + 0 ) * 1590.0000 / 2443.9238
= 0.0 Kg

Load Combination Results for Q + Wind or Seismic [Q]:
= Saddle Load + Max( Fwl, Fwt, Fsl, Fst )
= 19897 + Max( 1774 , 4286 , 7790 , 0 )
= 27688.2 Kg

Formulas and Substitutions for Horizontal Vessel Analysis:

Note: Wear Plates are assumed to be Welded k = 0.1

The Computed K values from Table 4.15.1:
K1 = 0.1066 K2 = 1.1707 K3 = 0.8799 K4 = 0.4011
K5 = 0.7603 K6 = 0.0529 K7 = 0.0410 K8 = 0.3405
K9 = 0.2711 K10 = 0.0581 K1* = 0.1923

Note: Dimension a is greater than or equal to Rm / 2.

Moment per Equation 4.15.3 [M1]:
= -Q*a [1 - (1- a/L + (R²-h2²)/(2a*L))/(1+(4h2)/3L)]
= -27688*1200.00[1-(1-1200.00/7850.00+(1411.000²-706.000²)/
(2*1200.00*7850.00))/(1+(4*706.00)/(3*7850.00))]
= -5744.4 Kg.m

Moment per Equation 4.15.4 [M2]:
= Q*L/4(1+2(R²-h2²)/(L²))/(1+(4h2)/( 3L))-4a/L
= 27688*7849/4(1+2(1411²-706²)/(7849²))/(1+(4*706)/
(3*7849))-4*1200/7849
= 17649.7 Kg.m

Longitudinal Stress at Top of Shell (4.15.6) [Sigma1]:
= P * Rm/(2t) - M2/(pi*Rm²t)
= 5.0 * 1411.000 /(2*10.00 ) - 17649.7 /(pi*1411.0²*8.00 )
= 317.49 Kg/cm²

Longitudinal Stress at Bottom of Shell (4.15.7) [Sigma2]:
= P * Rm/(2t) + M2/(pi * Rm² * t)
= 5.2 * 1411.000 /(2 * 10.00 ) + 17649.7 /(pi * 1411.0² * 8.00 )
= 399.92 Kg/cm²

Longitudinal Stress at Top of Shell at Support (4.15.8) [Sigma3]:
= P * Rm/(2t) - M1/(pi * Rm² * t)
= 5.0 * 1411.000 /(2 * 10.00 ) - -5744.4 /(pi * 1411.0² * 10.00 )
= 361.93 Kg/cm²

Longitudinal Stress at bottom of Shell at Support (4.15.9) [Sigma4]:
= P * Rm/(2t) + M1/(pi*Rm²t)
= 5.0 * 1411.000 /(2*10.00 ) + -5744.4 /(pi*1411.0²*10.00 )
= 343.57 Kg/cm²

Maximum Shear Force in the Saddle (4.15.5) [T]:
= Q(L-2a)/(L+(4*h2/3))
= 27688 ( 7850.00 - 2 * 1200.00 )/(7850.00 + ( 4 * 706.00 /3))
= 17164.7 Kg

Shear Stress in the shell with a single ring (4.15.13) [tau1]:
= T / ( pi * Rm * t )
= 17164.70 / ( pi * 1411.0000 * 10.0000 )
= 38.72 Kg/cm²

Decay Length (4.15.22) [x1,x2]:
= 0.78 * sqrt( Rm * t )
= 0.78 * sqrt( 1411.000 * 10.000 )
= 92.653 mm.

Circ. Stress in shell w/ring in Plane of Saddle (4.15.32) [sigma6*]:
= -K5 * Q * k/A
= -0.760 * 27688 * 0.1/55.63
= -37.84 Kg/cm²


In this example I can find the shears for Wind or Earthquake, but where is the moments indicates?
The maximum shear is in wind case or earthquake? It's not clear.

On the other hand, when I have a little vessel support with legs, I suppose the shears and moments indicates are in the base, not in the junction with the shell. It is correct?
Thanks in advance for your cooperation.

Regards

Top
#40941 - 02/14/11 08:16 AM Re: Moments and Shears in legs and saddles [Re: MARVIC2110]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 743
Loc: Houston, TX
Hello Folks

The moment and shear force are not given directly by PV Elite. We give the worst load on the saddle (Q).
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

Top



Who's Online
1 registered (Ahmed_Kamal), 32 Guests and 2 Spiders online.
Key: Admin, Global Mod, Mod
May
Su M Tu W Th F Sa
1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31
Forum Stats
12065 Members
14 Forums
16973 Topics
75151 Posts

Max Online: 303 @ 01/28/20 11:58 PM
Top Posters (30 Days)