STRESS-DISTRIBUTION AND CRACKING BEHAVIOR AT ANCHORAGE ZONES IN PRESTRESSED CONCRETE MEMBERS

Recently, several prestressed concrete structures have experienced sev ere cracking along the tendon path when prestress farce has been trans ferred in the anchorage zone. the purpose of the present study is to e xplore characteristics of the local stress distribution and to study t he failure mechanism on the anchorage zones of the precast prestressed concrete structures. To accomplish these objectives, a comprehensive experimental and analytical study has been conducted. Major variables include section geometry tendon profile and types of local reinforceme nts. From this study, it is found that the failure of rite anchorage z ones is initiated by the cracks along the tendon path and eventually s udden explosive failure with complete destruction on the anchorage zon es. Section geometry such as tendon inclination, tendon eccentricity a nd concrete cover thickness affect the cracking and ultimate loads. Th e cracking and ultimate load capacities for spirally reinforced anchor age zones are found to be larger than those for orthogonal reinforced anchorage zones. A new concept of failure mechanism on the anchorage z one is suggested, and the proposed concept describes well the failure process of prestressed concrete members.