<p>The influences of different factors, including whether the transverse frames are actually built, longitudinal and transverse welding residual stresses, and unloaded edge boundaries, on the ultimate strength and failure mode of a real hull bottom full-scale stiffened plate under axial compression and lateral pressure are investigated via numerical analysis. Result shows that the failure mode of the stiffened plate under axial compression is the tripping of the stiffeners. Whether transverse frames are built has little effect on the ultimate strength of the stiffened plate under axial compression, which can be replaced by the degree of freedom constraint. However, when lateral pressure is present, the transverse frame cannot be simply replaced by a free-degree constraint. The longitudinal residual stress has a greater effect on the ultimate strength, whereas the effect of the transverse residual stress is smaller. Stronger unloaded edge boundary conditions can slightly enhance the stiffness and ultimate strength of the stiffened plate. Under combined axial compression and lateral pressure, the failure mode of stiffened plates changes from the tripping of stiffeners to beam-column failure, as the lateral pressure increases. The ability of stiffened plates in which transverse frames are actually built out to resist beam-column shape deformation becomes weaker with lower ultimate strength. Stronger unloaded edge boundary conditions can improve the ability of stiffened plates to resist beam-column deformation and increase the ultimate strength.</p>