Fatigue behavior and life prediction of frost-damaged reinforced concrete beams under water submersion: Experimental and numerical study

Reinforced concrete (RC) bridge deck slabs in cold regions are frequently subjected to both fatigue loading and freeze–thaw cycles (FTC), leading to progressive deterioration. However, current design approaches typically treat these mechanisms independently, which may result in non-conservative service life predictions. To elucidate the influence of FTC on fatigue performance, three-point bending fatigue tests were conducted on RC beams under dry, submerged, and combined FTC and submersion conditions. Under severe frost damage, fatigue life is reduced by 80% relative to wet fatigue and by up to 98.3% relative to dry fatigue. A finite element model was developed and calibrated within a multi-scale computational framework to quantitatively analyze the fatigue behavior of frost-damaged RC beams. Based on numerical and experimental results, an empirical prediction formula was proposed for the reduction factor for wet fatigue life ( R F ) from the relative dynamic modulus of elasticity (RDME).