Investigation of crack propagation of the concentric anchorage zones based on linear elastic fracture mechanics

In the past decades, significant progress has been made in prediction of the structural behavior of the posttensioned anchorage zones, an aspect which has not yet been sufficiently clear up, however, is the serviceability behavior of posttensioned anchorage zones, especially with regard to the crack formation. To address this problem, a numerical method based on linear elastic fracture mechanics is proposed to investigate the crack propagation in posttensioned anchorage zones, and predict the structural behavior in the serviceability state. Following Irwin's approach, an effective crack length is proposed for I-II mixed-mode crack growth. The numerical analyses of the tested anchorage zone specimens show that the proposed procedure is able to accurately describe the crack propagation behavior, including crack length, crack width, and crack trace. Parameter analysis is performed to study the effects of the layout of the reinforcement on crack width in the service state. The results show that the proper bursting rebar diameters and rebar spacing can lead to the significant decrease of the crack width, while the longitudinal rebar makes little contribution to cracking control.