ABSTRACT
ART. 6.1 . INTRODUCTION C o n c r e t e is strong in compression: and since the basic function of columns in most normal frameworks is to carry vertical loads down to some lower level (generally to the foundations) it might seem at first that here at least was a component it should be possible to design without a great deal of intricate calculation. And yet in fact the design of columns frequently proves to be as laborious as any other part of a reinforced-concrete frame, if not more so. This is because in continuous rigid-jointed construction, part of the effect of loads on beams or slabs is the transmission of bending into the columns. Even internal columns in frameworks of structural symmetry are subject to out-of-balance bending moments, as for example when superimposed loads are applied on the floor on one side of the columns but not on the other. And the empirical method of design for flat-slabs (Article 5.5) is very reasonably dependent on internal columns being designed to resist bending moments equal to 50 per cent of the negative moment in the column strips of the slabs they support.
