In this paper, eight one-span single-storey industrial steel building structures with cranes were investigated by using three-dimensional analyses under equivalent longitudinal static seismic loads. The investigation parameters included the frame spans of 20, 26, 32 and 38 m; crane capacities of 100 and 200 kN; and construction locations in Hanoi and Son La regions. As a result, the maximum bending moments at the bottom of the columns in out of the frame plane induced by longitudinal seismic loads were very small and can be ignored, while the axial forces in the columns were considerably large, particularly in columns with longitudinal braces. Considering combination of internal forces due to dead loads and seismic loads for the columns, the compressive forces obtained when considering all three seismic load components acting transversely, vertically and longitudinally were significantly larger than those when considering only two transversal and vertical seismic load components, resulted from 2.36 to 2.99 times. The obtained results show that the compressive forces induced in columns due to longitudinal seismic loads were significantly increased, especially for those with braces and consequently this increase must be taken into account in the seismic design of single-storey industrial steel building structures with cranes, which depends on the span length and seismic intensities.