Prestress factors in CSM

SOFiSTiK
1

Hi everyone.

I have a question about the prestress factors which are used in SLS checks.

According to eurocode ΕΝ1992-1-1 - 5.10.9 for serviceability and fatigue calculations, prestress action should be multiplied by the following factors (rsup, rinf):
TYPE 1: pre-tensioning or unbonded tendons: rsup = 1.05 and rinf = 0.95
TYPE 2: post-tensioning with bonded tendons: rsup = 1.10 and rinf = 0.90
TYPE 3: when appropriate measures (e.g. direct measurements of pretensioning) are taken: rsup = rinf = 1.00
I am currently working on a bridge with type 2 & 3 tendons as mentioned above. Can CSM generate load combinations with the correct prestress factors simultaneously for both types of prestress? (type 2-> rsup = 1.10 and rinf = 0.90 & type 3-> rsup = rinf = 1.00)

Thanks in advance

2

I dont think CSM can do that but I like to be corrected. Usually we apply the factors in AQB.

3

Hi,

you change Pk,inf/sup with command CTRL PKIN and CTRL PKSU in CSM.
Value VAL is for P_1 and V2 is for P_2, so you can apply your PT as P_1 and P_2 with approperiate inf/sup factors

4

I have changed the Pk,inf/sup factors in CSM using prestress actions P_1 & P_2 and the following error occurred:

+++++ error no. 335 in program PKIN
CTRL PKIN only made for P_0 and P_1 usage, not for P_1 and P_2 usage!
Because V2 acts on P_1 and V3 on P_2 (confusing on P_1 and P_2 usage)
If you really have P_1, P_2, P_3 … without P_0 you can
switch off this error message with CTRL WARN 335.

Could you please explain to me the purpose of actions P_0, P_1, P_2,P_3 ?

I have also tried using actions P_0, P_1 with the following lines in CSM:

$----------------------------------------
CTRL PKIN VAL 1.00 V2 1.10
CTRL PKSU VAL 1.00 V2 0.90
$----------------------------------------

and I think it worked. Is my assumption correct ?