Structural elements of actual structures usually have several kinds of imperfections ; initial deflections, residual stresses, unexpected discontinuities of structural components and so on. These imperfections may severely weaken the strength of structures designed based on the ideal states of structures.
It is necessary to clarify the effects of imperfections not only qualitatively but also quantitatively. The theoretical analysis of the structures with imperfections, however, will not so easy in many cases partly because linear problems will become non-linear ones and in some cases two dimensional problems will become three dimensional ones and partly because it will be difficult to consider a suitable analytical models for so small amount of imperfections.
In this paper, the effects of initial deflections of columns on the compressive maximum loads are investigated where columns are assumed to be under the combined states of axial compression and one-dimensional bending.
The compression tests of 20 rectangular section columns and 8 H-type section columns with sine half wave type initial deflections were conducted.
The analytical solutions were computed by using incremental Finite Element technique. The accordance of both results was satisfactory.
Moreover, the maximum compressive loads of columns with irregular type initial deflections or with rotationally restrained ends were obtained theoretically.