Fig 3-26 The fix connection (portal frame)prevents the displacement JF PINNED, IF FIXED,ROTATION ROTATION IS ALLOWED (b) IS RESISTED DEFLECTIONS LARGE DEFLECTIONS REDUCED ELEVATIONS OF 4 COLUMN SPACE-STRUCTURE UNDER HORIZONTAL LOAD DL 一IF PINNED, IF FIXED BUCKLING 15 BUCKLING IS MORE LIKELY LESS LIKELY (ROTATION ALLOWED) (ROTATION RESTRAINED) (c) (d) ELEVATIONS OF 4 COLUMN SPACE-STRUCTURE UNDER VERTICAL LOADFig 3-26 The fix connection (portal frame) prevents the displacement