Effects of vertical seismic actions on the responses of single-storey industrial steel building frames

Single-storey industrial steel frames with crances are considered as being vertically irregular in structural configuration and load distribution under strong earthquake excitations. In this paper, various analytical frames with their spans of 20, 26, 32 and 38 m and locations built in Ha Noi and Son La regions were designed to resist dead, roof live, crane and wind loads. The equivalent horizontal and vertical static earthquake loads applied on the frames were determined. Next, by using linear elastic analyses of structures, the effects of vertical seismic actions on the responses of the frames were evaluated in terms of the ratios K1 and K2 at the bottom and top of the columns corresponding to different combinations of dead loads and static earthquake loads, as denoted by CE1, CE2 and CE3. The effects of seismic actions compared with those of wind actions were also evaluated in terms of the ratios K3 and K4. As a result, the effects of vertical seismic actions were significant and increased with the span lengths of the frames. In addition, by using nonlinear inelastic analyses of structures, the levels of the static earthquake loads were determined corresponding to the first yielding and maximum resistances of the frames. Keywords: single-storey industrial buildings; steel frames; span lengths; irregularity; vertical seismic actions; earthquake levels; wind loads