It is useful to consider the physical meaning of the charge combination. Each combination indicates the effects that may be present in the structure at a certain time. As a general rule, an effect in combination X does not act at the same time as an effect in combination Y. For example, 1.4G+1.6Q is the situation where the building is affected by vertical effects in a stationary state in the long term (no earthquake). 0.9G+E is roughly the case of an earthquake while the building is under construction. In general, the most unfavorable situation for vertical bearing elements comes from this combination because the normal force is low and the moments are high. G+Q+E is the case of an earthquake when the building is in use. Therefore, at a certain moment only one of these states will be present in the structure and the elements will only receive influences under that combination, that is, with the moment M2 in a loading d Since the M3 moment in the other loading or the normal force in another loading will not act on the elements at the same time, the design is made on the basis of the reinforcement areas calculated from the internal forces of each combination, and the combination is selected as the design combination that requires the most reinforcement area. The axial force has an indirect effect on the design by changing the moment carrying capacity of the element (thereby changing the reinforcement requirement). As a direct axial force design, it is only checked whether it exceeds the upper limits set by the regulation.