There are two point of views regarding the presence of beam web openings. The first attitude is treating the opening as non-intentional weakness imposed by non-structural necessities. The second and newly proposed attitude is to use these weakening parts as intentionally placed fuse elements to improve the seismic behaviour of the entire frame. In both cases, the existence of gravity loads on the beam causes an asymmetry in distribution of the internal forces of the beam when the frame is subjected to the lateral loads. This will cause, the different behaviour of the openings at two sides of the beam. This study evaluates the effects of gravity loads on the seismic behaviour of steel moment resisting frames with reduced web beams. For this purpose, two series of numerical models at beam and frame scales are developed and analysed under different levels of gravity loads. Based on the results, the unbalancing gravitational bending moment at the centre of openings causes the asymmetric yielding of the openings making one of the openings more critical.
