This research presents a multi-scale modeling approach to examine the behavior of an anchorage region in concrete girders strengthened with post tensioned Near-surface Mounted (NSM) carbon fiber reinforced polymer (CFRP) composites. Investigation methods include three dimensional continuum finite element and discrete object physics models to cover macro- and meso-scale behavior, respectively. Sequential coupling is used to link these various scale responses. A significant portion of the energy induced by post tensioned NSM CFRP is dissipated near the bottom flange of the strengthened girders at their anchorage location from macro-scale perspectives. The meso-scale model explains such energy dissipation occurs in the concrete-anchor bolt interface. The discrete object physics method is believed to be particularly useful for simulating the interaction between the anchorage components and contacting concrete substrate, including the interfacial failure process of the anchorage components while tensioning the CFRP composites. Predicted results explain the dynamic progress of damage in the anchorage zone, along with concrete crack development and stress transformation. The detailed failure mechanism of the anchorage for post tensioned NSM CFRP composites at a material level is elucidated.
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