Compression flange, buckling

Buckling of compression flange (one edge pinned, one edgefree)... 

Compression flange buckling Lateral torsional buckling Partial coefficients ULS SLS... 

It was hoped that frame failure would initiate in the connections. However, it appears that initial imperfections (identified in a cross-section dimension survey reported in reference 5 promoted local buckling in the beam compression flange which eventually resulted in cracking of the web-flange junction at mid-span before the moment capacities of the beam-column joints were exhausted. 

Specimen SLCOl/02 did not fail after 90/120 min, when experiments were stopped. The noncooled specimen SLC03, however, failed after 57 min. Post-fire inspection showed delamination cracks at the web-flange junctions and local buckling at the compressed upper face sheet and webs (see Figure 7.7). In order to understand the failure mode, the shear stress at the web-flange junction was calculated as follows ... 

P(5) The minimum ratio of flange width to flange thickness shall be determined to sustain the required compressive stress in the flange without local buckling. 

High-speed video images of the sequence of buckling and faiiure of a short, pultruded GFRP WF column subjected to axial compression (a) the post-locally buckled state immediately prior to failure initiation, (b) the instant of failure initiation at the left web-flange junction (see arrow head) and (c) development of further failure at both web-flange junctions and in the web. 

Column web buckling and beam flange buckling under compression are not considered in such modeling procedure. 

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