There are many collapse of steel building that equipped with crane, which did not knew what are root caused of their collapse. The forensic engineering have been done to find out root cause of the collapse, however the most of collapse case happened on crane have been used for many time, as known that every time crane move is cyclic loading and cause dynamic effect that will reduce the capacity of structure to sustain the exerted load, this phenomena in technical term known as fatigue of material (especially happened on steel structure). Fatigue, is the damage or collapse of structure element caused by dynamic effect of repeated applied load in certain number of loading cycles. From this terminology it found that every steel structure elements have their number of cycles to sustain the repeated load (N), and this number of cycles related with the value of crane lifting load (L), that caused stress on the structure (S), the higher the load make higher stress on the structure (S) then the lower the number of cycles (N) and vice versa. In this research the AI apps have been built to give quick prediction on number of cycles (N) of steel building that sustain certain crane load which caused stress (S) on structure. The prediction accuracy minimum is eighty percent (80%).