Experimental Research on Fatigue Behavior of RC Beams Strengthened with Steel Plate-Concrete Composite Technique

Abstract

Based on fatigue experiments on eight reinforced concrete (RC) beams strengthened with the steel plate-concrete composite (SPCC) technique, the fatigue life and development trend of stiffness and strain of specimens under a constant amplitude fatigue loading were studied. The experimental results showed that the fatigue failure mode of the SPCC strengthened beams was the fatigue failure of the steel plate. The initial fatigue crack in the steel plate appeared near the weld toe of studs and then expanded through the plate. Unlike regular RC beams, the fatigue failure mode of the tested specimens was ductile. The amplitude of stress in the steel plate had the most important influence on the fatigue behavior of RC beams strengthened with the SPCC technique. The level and amplitude of stress in the steel plate should be strictly controlled in practical design, and therefore, the high-strength steel and thin steel plate were not suitable for RC beams strengthened with the SPCC technique. The prestress in the steel plate could improve the fatigue life of RC beams strengthened with the SPCC technique. The S-N curve of the tension steel plate, welded with studs specified in the British code of practice for bridge design, BS5400, was conservative for the design of steel plate in RC beams strengthened with the SPCC technique. Calculation models were pre- sented of the residual static capacity and stiffness of RC beams strengthened with the SPCC technique after fatigue failure. DOI: 10.1061/ (ASCE)ST.1943-541X.0000336. © 2011 American Society of Civil Engineers. CE Database subject headings: Steel plates; Composite materials; Load bearing capacity; Fatigue; Concrete beams; Reinforced concrete.