Kris SathiaBentley Technical Support Group
Objective:
To calculate the support forces at the base of a column by using P-DELTA Analysis. Only the Large Delta effect is considered.
Input Parameters:
Length of column = 12 ft = 144 in
E=29000 ksi
Section= W8X10
Lateral load= 5 kip
Vertical load= 3 kip
Calculation:
Mz at column base = H x L + P x ∆
where H = the lateral load
L = the length of column
P = the axial compression load and
∆ = the displacement due to the lateral load at the free end of the column.
= 5.5717”
Mz = 5*144 + 3*5.5717
= 736.715 kip-in
STAAD Input file:
STAAD SPACESTART JOB INFORMATIONENGINEER DATE 22-Sept-13END JOB INFORMATIONINPUT WIDTH 79UNIT FEET KIPJOINT COORDINATES1 0 0 0; 2 0 12 0;MEMBER INCIDENCES1 1 2;DEFINE MATERIAL STARTISOTROPIC STEELE 4.176e+006POISSON 0.3DENSITY 0.489024ALPHA 6.5e-006DAMP 0.03END DEFINE MATERIALset shearMEMBER PROPERTY AMERICAN1 TABLE ST W8X10CONSTANTSMATERIAL STEEL ALLSUPPORTS1 FIXEDPRINT MEMBER PROPERTIES ALLLOAD 1 LOADTYPE None TITLE Lateral LoadJOINT LOAD2 FX 5LOAD 2 LOADTYPE None TITLE Vertical LoadJOINT LOAD2 FY -3PERFORM ANALYSIS PRINT STATICS CHECKCHANGELOAD 3 LOADTYPE None TITLE Vertical + Lateral load REPEAT LOAD1 1.0 2 1.0PDELTA ANALYSIS LARGEDELTA PRINT STATICS CHECKunit kips inchesPRINT JOINT DISPLACEMENTS ALLPRINT MEMBER FORCESFINISH
Member End force output:
Solution Comparison: