Dear sir,
I would like to calculate GRP pipes with BS7159 code using Caesar II. But I’m not sure that this load cases combination is correct for this code.
Can someone confirm this load cases combination? If this one is not correct can you give me the correct one, please?

Load Case Name type Status Output Combination
1 W+H(HGR) HGR Suppress Disp/Force/Stress
2 W+T1+P1+H(HGR) HGR Suppress Disp/Force/Stress
3 WW+HP HYD Keep Disp/Force/Stress
4 (SUS) WNC SUS Keep Disp/Force/Stress
5 (SUS) WNC SUS Keep Disp/Force/Stress
6 (OPE) W+T1+P1+D3 OPE Keep Disp/Force/Stress
7 (SUS) W+P1+D3 SUS Keep Disp/Force/Stress
8 (OPE) W+T1+P1+D3+WIN1 OPE Keep Disp/Force
9 (OPE) W+T1+P1+D3+WIN2 OPE Keep Disp/Force
10 (OPE) W+T1+P1+D3+WIN3 OPE Keep Disp/Force
11 (OPE) W+T1+P1+D3+WIN4 OPE Keep Disp/Force
12 (OPE) W+T1+P1+D3+1.75WIN1 OPE Keep Disp/Force
13 (OPE) W+T1+P1+D3+1.75WIN2 OPE Keep Disp/Force
14 (OPE) W+T1+P1+D3+1.75WIN3 OPE Keep Disp/Force
15 (OPE) W+T1+P1+D3+1.75WIN4 OPE Keep Disp/Force
16 (OPE) W+T1+P1+D1+D3+U1 OPE Keep Disp/Force
17 (OPE) W+T1+P1-D1+D3-U1 OPE Keep Disp/Force
18 (OPE) W+T1+P1+D2+D3+U2 OPE Keep Disp/Force
19 (OPE) W+T1+P1-D2+D3-U2 OPE Keep Disp/Force
20 (OPE) W+T1+P1+D3+U3 OPE Keep Disp/Force
21 (OPE) W+T1+P1+D3-U3 OPEKeep Disp/Force
22 (EXP) L22=L6-L7 EXP Keep Disp/Force/Stress Algebraic
23 (OCC) L23=L8-L6 OCCSuppressDisp/Force/Stress Algebraic
24 (OCC) L24=L9-L6 OCCSuppressDisp/Force/Stress Algebraic
25 (OCC) L25=L10-L6OCCSuppressDisp/Force/Stress Algebraic
26 (OCC) L26=L11-L6OCCSuppressDisp/Force/Stress Algebraic
27 (OCC) L27=L12-L6OCCSuppressDisp/Force/Stress Algebraic
28 (OCC) L28=L13-L6OCCSuppressDisp/Force/Stress Algebraic
29 (OCC) L29=L14-L6OCCSuppressDisp/Force/Stress Algebraic
30 (OCC) L30=L15-L6OCCSuppressDisp/Force/Stress Algebraic
31 (OCC) L31=L16-L6OCCSuppressDisp/Force/Stress Algebraic
32 (OCC) L32=L17-L6OCCSuppressDisp/Force/Stress Algebraic
33 (OCC) L33=L18-L6OCCSuppressDisp/Force/Stress Algebraic
34 (OCC) L34=L19-L6OCCSuppressDisp/Force/Stress Algebraic
35 (OCC) L35=L20-L6OCCSuppressDisp/Force/Stress Algebraic
36 (OCC) L36=L21-L6OCCSuppressDisp/Force/Stress Algebraic
37 (OCC) L37=L23,L24 OCC Keep Disp/Force/Stress Max
38 (OCC) L38=L25,L26 OCC Keep Disp/Force/Stress Max
39 (OCC) L39=L37+L38 OCC Keep Disp/Force/Stress SRSS
40 (OCC) L40=L27,L28 OCC Keep Disp/Force/Stress Max
41 (OCC) L41=L29,L30 OCC Keep Disp/Force/Stress Max
42 (OCC) L42=L40+L41 OCC Keep Disp/Force/Stress SRSS
43 (OCC) L43=L31,L32 OCC Keep Disp/Force/Stress Max
44 (OCC) L44=L33,L34 OCC Keep Disp/Force/Stress Max
45 (OCC) L45=L35,L36 OCC Keep Disp/Force/Stress Max
46 (OCC) L46=L43+L44+L45 OCC Keep Disp/Force/Stress SRSS
47 (OCC) L47=L7+L37 OCC Keep Stress Scalar
48 (OCC) L48=L7+L38 OCC Keep Stress Scalar
49 (OCC) L49=L7+L39 OCC Keep Stress Scalar
50 (OCC) L50=L7+L40 OCC Keep Stress Scalar
51 (OCC) L51=L7+L41 OCC Keep Stress Scalar
52 (OCC) L52=L7+L42 OCC Keep Stress Scalar
53 (OCC) L53=L7+L43 OCC Keep Stress Scalar
54 (OCC) L54=L7+L44 OCC Keep Stress Scalar
55 (OCC) L55=L7+L45 OCC Keep Stress Scalar
56 (OCC) L56=L7+L46 OCC Keep Stress Scalar

Where :
W: Poids propre
T1:Température de calcul
P1: Pression de calcul
WW : Poids eau épreuve
HP : Pression d’épreuve
WIN1 : Vent selon +X
WIN2 : Vent selon –X
WIN3 : Vent selon +Y
WIN4 : Vent selon -Y
U1 : Séisme selon X
U2 : Séisme selon Y
U3 : Séisme selon Z
D1:Déplacement selon X
D2:Déplacement selon Y
D3:Tassement selon Z(négatif)


Thank you for advance

hello!
can someone reply me?
thanks

Typically, the evaluation of GRP pipe does not follow the standard B31 collapse and fatigue approach. Basically, you calculate the total stress at various states of the piping system and compare that total stress to a limit. For example, load cases 8 to 21 would be used for stress evaluation and load cases 47 to 56 would not be required.
I would suggest you first assure safe operation for installation and basic operation before you throw on all those occasional loads.

thank you Dave,
But if we use BS7159 for stress calculation, and according to section five the allowable stress SH is depending on pipe diameter.
I have GRP pipe with thoses characteristic:
- laminate type three:Ed=0.0018
axial elastic modulus long term:10000MPa
hoop elastic modulus long term:20000MPa
Sh=Ed.ELAM
ELAM=XLAM/td
according to paragraph 4.3 and section five i have the following value for all diameters:
DN Ref laminate td XLAM ELAM Sh(MPa)
80 L30 4.5 33000 7333 13.2
100 L40 5.2 42000 8077 14.54
150 L50 5.9 50000 8474 15.25
200 L60 6.7 58800 8776 15.79
250 L80 8.7 80000 9195 16.55
300 L100 10.6 100000 9434 16.98
350 L120 12.5 120000 9600 17.28
400 L120 12.5 120000 9600 17.28
There are very low vakue to be used
or in B31.3 Sh=0.5UDB=40MPa
If I run this model weith B31.3 it pass
but if I run it with BS7159 it can't pass
there a big difference in Sh value for B31.3 and BS7159
there no logical result!
normally there are a small difference between all code not over than 10%
can this modelization is correct?

Section 5 is Design for pressure containment. I am not sure you want to use that table for flexibility analysis. Flex analysis is Section 7 and there you have your stress calculations. In Section 7 it says that the maximum combined stress should not exceed the design stress for the laminate at any location. Although the wording is not consistent, Section 4 defines design stress as the design strain times the appropriate E. From your data, I would guess the design stress in hoop is 36MPa and 18MPa axial.

I thank you Dave
But in section 4 the Sh is calculated by:
Sh=Ed.ELAM
ELAM=XLAM/td
and Xlam is depending on diameters
you consider ELAM the manufacturer value of elasticity module! witch paragraph can approve this consideration?

I have no answer for you at the moment.
Maybe the pipe manufacturer can help here?