Good afternoon.
I used DFF and SELECT command to check a serviceability as shown below.
DEFINE ENVELOPE
201 TO 276 ENVELOPE 2 TYPE STRENGTH
901 ENVELOPE 8 TYPE SERVICEABILITY
END DEFINE ENVELOPE
**********************************************************************
LOAD LIST 201 TO 276
LOAD LIST ENV 8
PARAMETER 1
CODE AISC UNIFIED 2010
METHOD LRFD
FYLD 245000 MEMB _STEEL
DFF 200 ALL
DJ1 4 MEMB 4 31
DJ2 24 MEMB 4 31
DMIN 0.19 MEMB _STEEL
**********************************************************************
TRACK 2 MEMB _STEEL
CHECK CODE MEMB _STEEL
SELECT MEMB _RSG
*********************************************************************
FINISH
The code checking result is 'Pass' by 0.316 ratio with H194x150x6x9 section and relatively small deflection as shown below.
STAAD.PRO CODE CHECKING - (AISC-360-10-LRFD) v1.4a
********************************************
MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/
FX MY MZ LOCATION
=======================================================================
4 ST H194X150X6X9 (JAPANESE SECTIONS)
PASS DEFLECTION 0.316 901
8.29 0.07 13.46 5.02
|-----------------------------------------------------------------------|
| DEFLECTION CHECK: (UNIT: CM ) |
| |
| Limit Span/Deflection (DFF) : 200.000 Limit : 2.512 |
| Span/Deflection : 6.32E+02 Deflection : 0.795 |
| L/C : 901 LOC : 5.025 |
| Ratio : 0.316 (PASS) |
|-----------------------------------------------------------------------|
Even if the ratio is below 1.0, MEMBER SELECTION command find the huge section which is H498x432x45x70 for all members as shown below.
I expected the section not be changed because the ratio is below 1.0.
I have not defined any restriction for section so dont know why this big section is selected.
STAAD.PRO MEMBER SELECTION - (AISC-360-10-LRFD) v1.4a
***********************************************
MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/
FX MY MZ LOCATION
=======================================================================
4 ST H498x432x45x70 (JAPANESE SECTIONS)
PASS DEFLECTION 0.007 901
8.29 0.07 13.46 5.02
|-----------------------------------------------------------------------|
| DEFLECTION CHECK: (UNIT: CM ) |
| |
| Limit Span/Deflection (DFF) : 200.000 Limit : 2.512 |
| Span/Deflection : 2.86E+04 Deflection : 0.018 |
| L/C : 901 LOC : 5.025 |
| Ratio : 0.007 (PASS) |
|-----------------------------------------------------------------------|
Can you help me to resolve the problem?
Thanks.