Akademik Veri Yönetim Sistemi
Construction and Building Materials, cilt.522, 2026 (SCI-Expanded, Scopus)
Dynamic shear strength plays a critical role in the structural reliability of concrete elements subjected to cyclic and seismic loading conditions. However, most existing fatigue models are developed under quasi-static assumptions and generally neglect the influence of loading-rate effects on cyclic shear behavior. This study experimentally investigates the influence of loading rate on cyclic shear fatigue life and progressive strength degradation of concrete under displacement-controlled loading conditions. Monotonic direct shear tests were performed at different displacement rates to quantify the loading-rate dependency of shear strength through the Dynamic Increase Factor (DIF). The obtained DIF relationship was incorporated into a modified fatigue formulation by introducing a rate-dependent intercept parameter in the S–N curve. This modification allows the combined effects of loading rate and cyclic damage evolution to be represented within a unified framework. Experimental results demonstrate that increasing loading rate leads to a systematic enhancement in shear strength and significantly influences fatigue life predictions. The proposed rate-adjusted S–N relationship exhibits improved agreement with experimental observations compared with the classical formulation, yielding higher correlation (R²) values and lower root mean square error (RMSE). These findings indicate that incorporating loading-rate effects into fatigue assessment reduces the uncertainty associated with conventional fatigue models based on static reference strength. From an engineering perspective, the proposed framework provides a more realistic basis for evaluating fatigue performance and damage evolution in shear-critical concrete elements subjected to cyclic and seismic loading conditions.