Pdelta Analysis / Perform Analysis Command

RE: Pdelta Analysis / Perform Analysis Command

DSANJU — Mon, 02 Mar 2015 13:34:15 GMT

You have used correct commands.

RE: Pdelta Analysis / Perform Analysis Command

SantoS — Mon, 02 Mar 2015 13:14:14 GMT

Hi DSANJU,

Thank you for your reply.

Based on your explanation, the correct on should be like this?

Please your confirmation.

Thanks a lot.

**********************************************************
DEFINE IBC 2006 ACCIDENTAL
SS 1 S1 0.37 I 1 RX 8 RZ 8 SCLASS 3 TL 4 FA 1.005 FV 1.43
SELFWEIGHT 1
MEMBER WEIGHT
_ROOF UNI 1.86
FLOOR WEIGHT
_ROOFSLAB FLOAD 2.88
********************************************************************
LOAD 1 LOADTYPE Seismic TITLE EX
IBC LOAD X 1
PERFORM ANALYSIS
CHANGE

********************************************************************
LOAD 2 LOADTYPE Seismic TITLE EZ
IBC LOAD Z 1
PERFORM ANALYSIS
CHANGE
********************************************************************
LOAD 3 LOADTYPE Dead TITLE DEAD
SELFWEIGHT Y -1
FLOOR LOAD
_ROOFSLAB FLOAD -2.88 GY
MEMBER LOAD
_ROOF UNI GY -1.86
LOAD 4 LOADTYPE Live TITLE LIVE
FLOOR LOAD
_ROOFSLAB FLOAD -1 GY
********************************************************************

LOAD 5 1.4D
REPEAT LOAD
1 1.4
LOAD 6 1.2D+1.6L
REPEAT LOAD
1 1.2 2 1.6

LOAD 7 1.0D+0.7EX+0.3(0.7)EY
REPEAT LOAD
1 1 21 0.7 22 0.21 ......etc

PDELTA ANALYSIS
FINISH

RE: Pdelta Analysis / Perform Analysis Command

DSANJU — Mon, 02 Mar 2015 07:59:30 GMT

After the load case 1, you should use PERFORM ANALYSIS command followed by a CHANGE command. The same this should be done for the other static seismic load cases. You can find the effect of P-delta for the load combination where you have vertical and lateral load cases combined together- it is to be noted that you should use REPEAT LOAD commands to combine the primary load cases. You are rightly used PDELTA ANALYSIS command.