Bond Characteristics of Prestressing Tendons within Pre-tensioned Prestressed Concrete Members Damaged by a Fire and Evaluation of Their Residual Load Carrying Capacity

点击翻译按钮获取中文摘要

Bond strength between concrete and prestressing tendons, as well as residual prestress and load carrying capacity of pre-tensioned prestressed concrete beams decreased due to the effect of high temperature exposure by a fire. These decreasing ratio became larger with increasing in applied temperature and exposure time, and with decreasing in concrete cover.On the other hand, an increase in concrete cover thickness could restrain the enhancement of temperature in prestressing tendons and mitigate the reduction in bond strength and load carrying capacity. Especially, in the case of 70mm concrete cover, load carrying capaciry scarcely decreased even when subjected to 30 minutes heating up to 1100 degree centigrade.