Ultimate stress of unbonded tendon in continuous members

Mojtahedi and Gamble emphasised the effect of span/depth ratio from the study of continuous shallow specimens, which laid the ground for the revision of ACI 318-77 Code as ACI 318-83 Code. However, the fact that most specimens had failed prematurely before reaching their ultimate flexural capacities was overlooked. Specimens they referred to were not able to deform sufficiently because of improper reinforcing details or failure modes different to the flexural mode. Thus, the purpose of this study is to provide physical evidence for the overemphasis of current ACI Code (318-02) on the unbonded tendon stress of members with a high span/depth ratio. In this study, four new specimens were fabricated to the same specifications as the specimens of Burns et al., but in which bonded reinforcements were provided continuously. As a result, it was revealed that the current ACI Code, revised by the results of Mojtahedi and Gamble's study, overestimates the effect of span/depth ratio on shallow members.