FINITE ELEMENT MODELLING ON VIERENDEEL MECHANISM IN STEEL BEAMS WITH LARGE CIRCULAR WEB OPENINGS

摘要

The paper presents a finite element investigation on the VierendeeJ mechanism in steel beams with large circular web openings. A finite element model is established with both material and geometrical non-linearity so that the moment capacities of tee sections above and below the web openings may be accurately evaluated in the presence of co-existing axial and shear forces. Moreover, load redistribution across the web openings may be directly incorporated during the assessment of the load carrying capacities of steel beams with large circular web openings. An empirical shear moment interaction curve at the perforated sections is then proposed for practical design of steel beams with medium to large circular web openings against the Vierendeel mechanism. It is found that shear yielding in steel beams with large circular web openings is very important as it reduces the effectiveness of load re-distribution across the web openings. Consequently, the plastic moment capacities of tee sections at the low moment side of the web openings may not be mobilized fully.