Abstract
With request for larger RC structures and structural members in these days, longitudinal reinforcing bars are required to be large in size and to be placed in multi-layers in the cross scetion of members. This trend makes it nacessary to examine the applicability of present code equations for flexural crack widths of RC beams. Based on the experimental test results, it is discussed in this paper how the multi layers of longitudinal bars influence the flexural cracking of RC beams. Special attention is paid to how the location and the size of bars as well as the bounded bars influence the cracking behaviors. The test results show that the crack spacings and the crack widths of beams depend upon how the longitudinal bars are placed although the bars nearest to the concrete surface have dominant effects on cracking.
