| Abstrakt: |
The use of steel cellular beams (beams with circular shape of openings) has been increasing day by day because of its architectural appearance as well as many other advantages such as light in weight, enhancement in flexural strength and incorporation of pipes through the openings. But on the other hand, due to the presence of web openings, there is a sudden drop in the shear as well as flexural strength of the beams. To counteract this problem, there is a necessity to strengthen the cellular beams. Therefore, the objective of the present research work is to evaluate the buckling performance of cellular beams strengthened with flange cover plates. In the present study, the cellular beams are designed as per the Arcelor Mittal, ACB®and Angelina TM beams specification. The sections considered in the analysis are CB420, CB450 and CB480 which are fabricated from parent section ISMB300 by adopting the expansion ratio as 1.4h, 1.5hand 1.6h. The spacing is varied from 1.1a, 1.2aand 1.3a, where ‘a’ is the diameter of the opening. The diameter of openings are changed from 1.0h, 1.1h, 1.2hand 1.3hwhere ‘h’ is the height of the parent section, i.e. 300 mm. The FE analysis is performed using ABAQUS software. From the analysis results, it observed that by strength enhancement in cellular beam due to strengthening is 36.30% for CB420, 39.16% for CB450 and 43.08% for CB480. The centre-to-centre spacing of openings also plays a governing role on flexural strength of beams. As soon as spacing of openings increases, the strength increases and vice versa. The common modes of failure are excessive bending, local buckling, vierendeel mechanism and web-post buckling. The last two failure modes, i.e. vierendeel mechanism and web-post buckling are the most important failure modes of cellular beams which needs to be carefully addressed. |
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