Abstract
There have been developed several equations for estimating the flexural crack widths of RC beams, and some of them are now appreciated in code specifications. Since most of them are semi-empirical, their applicability should be examined whenever new types of structure come into consideration. One of the recent requirements for RC structures is to make them larger in size. As for the reinforcing bars, placement of bars in multi-layers in the cross section as well as usage of large sized bars is indispensable for design of large sized beams. This paper discussed firstly the applicability of present equations for flexural crack widths to the beams with multi-layers of longitudinal bars. The examination of applicability is extended using test results of 86 beam specimens which are deliberately selected so as to represent wide variety of arrangement of reinforcing bars. Based on the discussion the authors propose the equations for crack spacing and crack width with wide applicability.
