Hi Everyone,
I have the following structure modeled in STAAD and evaluated using ASCE 10-97. After reviewing some of the results, the utilization ratios are not in agreement with the hand calculations based on the forces being applied. I concentrate on member 881 which has an utilization of 24.5 which makes no sense. Please advice if I have input something wrong in the design component.
CODE ASCE 1997
FYLD 4752 MEMB 881
UNB 7.8 MEMB 881
UNT 7.8 MEMB 881
MAIN 5 MEMB 881
LEG 0 MEMB 881
SSY 1 ALL
SSZ 1 ALL
NHL 0 MEMB 881
TRACK 3 MEMB 881
CHECK CODE MEMB 881
UNIT INCHES KIP
LOAD LIST 20
PRINT MEMBER FORCES GLOBAL LIST 881
SECTION 0 0.25 0.5 0.75 1 MEMB 881
PRINT MEMBER SECTION FORCES LIST 881
PRINT MEMBER STRESSES LIST 881
FINISH
ALL UNITS ARE - KIP FEET (UNLESS OTHERWISE Noted)
MEMBER TABLE RESULT/ CRITICAL COND/ RATIO/ LOADING/
FX MY MZ LOCATION
=======================================================================
* 881 ST L25253 (AISC SECTIONS)
FAIL ASCE 3.12-1 24.572 20
6.59 C 0.04 0.66 3.89
AXIAL CAPACITY OF SECTION = 9.422
EULER CAPACITIES - Y AXIS, Z AXIS = 29.047, 6.860
MOMENT CAPACITY - Y AXIS = 1.204
MOMENT CAPACITY - Z AXIS = 0.695
BOLT CAPACITY = 11.421 NO OF BOLTS = 1 NET SECT. FACTOR = 1.000
SHEAR CAPACITY/ACTUAL SHEAR - Y AXIS = 5.997, 0.000
SHEAR CAPACITY/ACTUAL SHEAR - Z AXIS = 5.997, 0.000
ACTUAL/ALLOWABLE SLENDERNESS RATIOS = 165.444, 250.000
|---------------------------------------------------------------------|
************** END OF TABULATED RESULT OF DESIGN **************
2869. UNIT INCHES KIP
2870. LOAD LIST 20
2871. PRINT MEMBER FORCES GLOBAL LIST 881
STAAD SPACE -- PAGE NO. 346
MEMBER END FORCES STRUCTURE TYPE = SPACE
-----------------
ALL UNITS ARE -- KIP INCH (GLOBAL)
MEMBER LOAD JT FX FY FZ MX MY MZ
881 20 230 -0.03 0.00 6.59 0.00 0.00 0.00
232 -0.03 0.00 -6.59 0.00 0.00 -0.00
************** END OF LATEST ANALYSIS RESULT **************
2872. SECTION 0 0.25 0.5 0.75 1 MEMB 881
2873. PRINT MEMBER SECTION FORCES LIST 881
STAAD SPACE -- PAGE NO. 347
MEMBER FORCES AT INTERMEDIATE SECTIONS
--------------------------------------
ALL UNITS ARE -- KIP INCH
MEMB LOAD SEC AXIAL SHEAR-Y SHEAR-Z MOM-Y MOM-Z
881 20 0.25 6.59 -0.01 0.01 0.43 0.43
0.50 6.59 0.00 0.00 0.57 0.57
0.75 6.59 0.01 -0.01 0.43 0.43
************** END OF LATEST ANALYSIS RESULT **************
2874. PRINT MEMBER STRESSES LIST 881
STAAD SPACE -- PAGE NO. 348
MEMBER STRESSES
---------------
ALL UNITS ARE KIP /SQ INCH
MEMB LD SECT AXIAL BEND-Y BEND-Z COMBINED SHEAR-Y SHEAR-Z
881 20 .0 7.3 C 0.0 0.0 7.3 0.1 0.1
0.25 7.3 C 0.9 1.9 9.7 0.0 0.0
0.50 7.3 C 1.2 2.6 10.5 0.0 0.0
0.75 7.3 C 0.9 1.9 9.7 0.0 0.0
1.0 7.3 C 0.0 0.0 7.3 0.1 0.1
************** END OF LATEST ANALYSIS RESULT **************