Fatigue Behavior and Design of Ferrocement Beams

Extensive experiments were carried out on ferrocement beams reinforced with various amounts (volume fraction from 2% to 6%) and types of square steel meshes. The beams were subjected to fatigue flexure with three levels of loading corresponding to approx —40%, —50%, and —60% of static yield load. Particular emphasis was given to the shape of the load-deflection curve and the cracking behavior as influenced by the number of loading cycles. Based on observed results linear regression equations are proposed to predict fatigue life of ferrocement as a function of the stress range in the outermost layer of steel mesh. Also, an exponential relation with two parameters is developed to predict the increase in deflection, average and maximum crack widths as a function of applied load, and number of loading cycles. The preceding relations are shown to be usefully adaptable to reinforced concrete beams subjected to fatigue flexure.