Good day Everyone!
I have several warnings in what I'm trying to design.
I designed this model in STAAD TRUSS since this is a truss.
Below are the details. Thanks in advance.
P R O B L E M S T A T I S T I C S ----------------------------------- NUMBER OF JOINTS 121 NUMBER OF MEMBERS 197 NUMBER OF PLATES 0 NUMBER OF SOLIDS 0 NUMBER OF SURFACES 0 NUMBER OF SUPPORTS 22
SOLVER USED IS THE OUT-OF-CORE BASIC SOLVER
ORIGINAL/FINAL BAND-WIDTH= 102/ 18/ 45 DOF TOTAL PRIMARY LOAD CASES = 4, TOTAL DEGREES OF FREEDOM = 297 TOTAL LOAD COMBINATION CASES = 5 SO FAR. SIZE OF STIFFNESS MATRIX = 14 DOUBLE KILO-WORDS STAAD TRUSS -- PAGE NO. 7
REQRD/AVAIL. DISK SPACE = 12.5/ 871950.9 MB
*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 11 EQN.NO. 1 LOADS APPLIED OR DISTRIBUTED HERE FROM ELEMENTS WILL BE IGNORED. THIS MAY BE DUE TO ALL MEMBERS AT THIS JOINT BEING RELEASED OR EFFECTIVELY RELEASED IN THIS DIRECTION.*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 55 EQN.NO. 4*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 88 EQN.NO. 7*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 89 EQN.NO. 10*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 60 EQN.NO. 13*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 90 EQN.NO. 16*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 61 EQN.NO. 19*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 91 EQN.NO. 22*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 62 EQN.NO. 25*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 92 EQN.NO. 28*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 63 EQN.NO. 31*WARNING- ZERO STIFFNESS IN DIRECTION 1 AT JOINT 93 EQN.NO. 34 **WARNING - THERE WERE MORE THAN 12 DOF WITH ZERO STIFFNESS. THE FIRST 12 ARE LISTED ABOVE. TOTAL # TRANSLATIONAL= 84 TOTAL # ROTATIONAL= 0 ***WARNING - INSTABILITY AT JOINT 121 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 4.4049210E+02 L-MATRIX DIAG= 3.6663829E-07 EQN NO 54 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY **NOTE** STAAD DETECTS INSTABILITIES AS EXCESSIVE LOSS OF SIGNIFICANT DIGITS DURING DECOMPOSITION. WHEN A DECOMPOSED DIAGONAL IS LESS THAN THE BUILT-IN REDUCTION FACTOR TIMES THE ORIGINAL STIFFNESS MATRIX DIAGONAL, STAAD PRINTS A SINGULARITY NOTICE. THE BUILT-IN REDUCTION FACTOR IS 1.000E-09 THE ABOVE CONDITIONS COULD ALSO BE CAUSED BY VERY STIFF OR VERY WEAK ELEMENTS AS WELL AS TRUE SINGULARITIES. ***WARNING - INSTABILITY AT JOINT 8 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 4.0197194E+01 L-MATRIX DIAG= 7.1054274E-15 EQN NO 65 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 41 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 6.1183192E+02 L-MATRIX DIAG= 3.9748602E-07 EQN NO 72 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 2 DIRECTION = FX PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.2704715E+02 L-MATRIX DIAG= -4.0103032E-11 EQN NO 73 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY STAAD TRUSS -- PAGE NO. 8
***WARNING - INSTABILITY AT JOINT 2 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 1.4603033E+01 L-MATRIX DIAG= -2.4886759E-12 EQN NO 74 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 2 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.3650660E+02 L-MATRIX DIAG= -4.1524117E-11 EQN NO 75 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 4 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 1.4743329E+01 L-MATRIX DIAG= 3.5527137E-15 EQN NO 95 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 4 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.3408224E+02 L-MATRIX DIAG= -2.8421709E-14 EQN NO 96 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 118 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 4.4165583E+02 L-MATRIX DIAG= 0.0000000E+00 EQN NO 114 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 119 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 4.5418037E+02 L-MATRIX DIAG= 2.3703706E-11 EQN NO 117 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 38 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.9622196E+02 L-MATRIX DIAG= 5.6843419E-14 EQN NO 153 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 124 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 4.5490480E+02 L-MATRIX DIAG= 8.2428642E-10 EQN NO 156 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 1 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 1.4522596E+01 L-MATRIX DIAG= 1.7763568E-15 EQN NO 188 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 1 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.3057744E+02 L-MATRIX DIAG= 0.0000000E+00 EQN NO 189 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 39 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 6.1455070E+02 L-MATRIX DIAG= 1.9194886E-09 EQN NO 192 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY STAAD TRUSS -- PAGE NO. 9
***WARNING - INSTABILITY AT JOINT 6 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 3.9099370E+01 L-MATRIX DIAG= 7.1054274E-15 EQN NO 194 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 3 DIRECTION = FX PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.3288038E+02 L-MATRIX DIAG= -3.6948222E-11 EQN NO 226 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 3 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 1.4667662E+01 L-MATRIX DIAG= -2.3252511E-12 EQN NO 227 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 3 DIRECTION = FZ PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 2.3288195E+02 L-MATRIX DIAG= -3.6919801E-11 EQN NO 228 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 75 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 5.6258032E+03 L-MATRIX DIAG= 1.8189894E-12 EQN NO 242 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 54 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 5.5161260E+03 L-MATRIX DIAG= 4.9476512E-10 EQN NO 284 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY ***WARNING - INSTABILITY AT JOINT 43 DIRECTION = FY PROBABLE CAUSE SINGULAR-ADDING WEAK SPRING K-MATRIX DIAG= 5.5161260E+03 L-MATRIX DIAG= -6.9212547E-10 EQN NO 296 ***NOTE - VERY WEAK SPRING ADDED FOR STABILITY 290. LOAD LIST 5 TO 8 291. FINISH *********** END OF THE STAAD.Pro RUN ***********