hello guys can anyone answer me for this point, what's different between specification beam (Release) and normal beam of the structure? the specification beam (release) will remove ?

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 05-Dec-22
END JOB INFORMATION
INPUT WIDTH 79
UNIT METER KN
JOINT COORDINATES
1 0 0 0; 2 10 0 0; 3 0 5 0; 4 10 5 0; 5 0 0 10; 6 10 0 10; 7 0 5 10; 8 10 5 10;
9 1.66667 5 0; 10 3.33333 5 0; 11 5 5 0; 12 6.66667 5 0; 13 8.33333 5 0;
14 1.66667 6 0; 15 3.33333 7 0; 16 5 8 0; 17 6.66667 7 0; 18 8.33333 6 0;
19 1.66667 5 10; 20 3.33333 5 10; 21 5 5 10; 22 6.66667 5 10; 23 8.33333 5 10;
24 1.66667 6 10; 25 3.33333 7 10; 26 5 8 10; 27 6.66667 7 10; 28 8.33333 6 10;
MEMBER INCIDENCES
1 3 9; 2 1 3; 3 2 4; 4 7 19; 5 5 7; 6 6 8; 7 3 7; 8 4 8; 9 9 10; 10 10 11;
11 11 12; 12 12 13; 13 13 4; 14 19 20; 15 20 21; 16 21 22; 17 22 23; 18 23 8;
19 3 14; 20 14 15; 21 15 16; 22 16 17; 23 17 18; 24 18 4; 25 9 14; 26 10 15;
27 11 16; 28 12 17; 29 13 18; 30 10 14; 31 11 15; 32 11 17; 33 12 18; 34 7 24;
35 24 25; 36 25 26; 37 26 27; 38 27 28; 39 28 8; 40 19 24; 41 20 25; 42 21 26;
43 22 27; 44 23 28; 45 20 24; 46 21 25; 47 21 27; 48 22 28; 49 9 19; 50 10 20;
51 11 21; 52 12 22; 53 13 23; 54 14 24; 55 15 25; 56 16 26; 57 17 27; 58 18 28;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 210
POISSON 0.3
DENSITY 76.8195
ALPHA 1.2e-005
DAMP 0.03
TYPE STEEL
STRENGTH FY 253200 FU 407800 RY 1.5 RT 1.2
ISOTROPIC STAINLESSSTEEL
E 1.9793e+008
POISSON 0.3
DENSITY 76.8195
ALPHA 1.8e-005
DAMP 0.03
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
19 TO 58 TABLE ST W6X9
1 TO 18 TABLE ST W8X48
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 2 5 6 FIXED
MEMBER RELEASE
19 TO 48 54 TO 58 START MX MY MZ
DEFINE REFERENCE LOADS
LOAD R1 LOADTYPE None TITLE REF LOAD CASE 1
END DEFINE REFERENCE LOADS
LOAD 1 LOADTYPE Dead TITLE LK
JOINT LOAD
3 4 7 8 14 TO 18 24 TO 28 FY -144
PERFORM ANALYSIS
FINISH