Effect of fatigue stress amplitude on the 5000 cycle residual strength of non-adhesive filament wound concrete composites under compression

Two layers of aluminum foils are inserted between the concrete column and the filament wound glass/epoxy composite jacket to form a non-adhesive wrapping for concrete columns. Different compressive fatigue stress amplitudes are applied on the concrete specimens to investigate their compressive strength after fatigue. Experimental results show that the compression after fatigue (CAF) strength of the non-adhesive filament wound composite/concrete columns is better than that of a pure concrete column under the same fatigue cycle and stress amplitude. The CAF strength of both concrete columns and composite/concrete columns is dominated by the pre-applied fatigue stress amplitude when it is greater than 1/3 of the compression strength of the plain concrete column. For stress amplitude less than this threshold value, the CAF strength reduction is less than 5%. The hysteretic loops during the fatigue cycle are recorded to evaluate the energy dissipation of both concrete and composite/concrete systems. The stress–strain curve of the CAF coupons is measured to locate the influence of stress amplitude on the lateral compliance of the composite/concrete system. Statistical prediction models of CAF strength for concrete and composite/concrete systems correlate well with the experimental data.