*HEADING
  THREE DIMENSIONAL FRAME STRUCTURE WITHOUT SUPERELEMENTS   
*NODE
 1, -4., -4.
11, -4., -4., 2.4
21,  4., -4., 2.4
31,  4., -4.
1001, -4.,  4.
1011, -4.,  4., 2.4
1021,  4.,  4., 2.4
1031,  4.,  4.
*NGEN
1,11
11,21
21,31
1001,1011
1011,1021
1021,1031
11,1011,100
21,1021,100
*ELEMENT,TYPE=B31
1,1,2
1001, 1001,1002
101,11,111
111,21,121
*ELGEN,ELSET=PLANE
1,30
1001,30
*BEAM SECTION,SECTION=RECT,MATERIAL=STEEL,ELSET=PLANE
0.1 , 0.1
 0, -1.
3,3
*ELGEN,ELSET=ANGLE
101,10,100,1
111,10,100,1
*BEAM SECTION,SECTION=RECT,MATERIAL=STEEL,ELSET=ANGLE
0.1 , 0.1
 -1.,
3,3
*ELSET,ELSET=ROOF,GENERATE
11,20
1011,1020
101,120
*MATERIAL,NAME=STEEL
*ELASTIC
2.1E11 , 0.3
*DENSITY
7200., 
*BOUNDARY
1,1,6
31,1,6
1001,1,6
1031,1,6
*RESTART, WRITE
*STEP,PERTURBATION
*STATIC
*DLOAD
ROOF,PZ, -235.
*NODE PRINT
U, 
RF, 
*NODE FILE
U, 
RF, 
*OUTPUT,FIELD
*NODE OUTPUT
U,
RF,
*EL PRINT,FREQUENCY=0
*END STEP
*STEP
*FREQUENCY, eigensolver=lanczos
10, , 
*NODE FILE,FREQUENCY=0
*OUTPUT,FIELD,FREQ=0
*NODE OUTPUT
*MODAL FILE
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP