Load bearing mechanisms of lap splices under tension were investigated by one of the discrete analytical methods, called Rigid Body Spring Model, RBSM. Influences of splice length and clear space on the splice strength were evaluated focusing on internal cracks and stress distribution of concrete to clarify the bearing mechanisms of lap splices. As the results of analyses, it was confirmed that compression struts were formed in the concrete between splice rebars, and the performance of the lap splice depended on the magnitude of the stress in those struts and their spread.
