To address the prominent issues of unclear damage evolution mechanism and difficulty in quantitatively characterizing the quasi-stable state of the unguided hydraulic climbing formwork corbels under asymmetric cyclic loading, a multi-scale study from macro to micro was conducted. Based on the Chaboche nonlinear kinematic hardening constitutive model, a refined finite element model of the node was established using ABAQUS to simulate the cyclic mechanical behavior under the construction load spectrum. Combined with nanoindentation simulation, the micro-mechanical responses at different damage levels were obtained. The results show that the damage evolution of the node presents three-stage characteristics: cyclic softening, damage localization, and micro-instability. The edge of the bolt hole is the core area of damage, and the maximum reduction in macroscopic bearing capacity is up to 12.8%. There is a mechanism transition in the damage evolution. When the damage variable D > 0.15, the dominant mechanism changes from the overall material yield softening to the aggregation of defects and local instability. The critical instability time point of micro-scale energy dissipation is sensitive to the damage state. For the node and load conditions, the damage calibration relationship established based on the critical instability time offset and cumulative plastic dissipation energy density has a goodness of fit greater than 0.98, achieving quantitative mapping of macro and micro damage states. This provides a micro-mechanical basis for node damage assessment. The relevant control measures have effectively controlled the damage level within the safety requirements in engineering practice, verifying the rationality and engineering applicability of the proposed method.