Title: Effect of Deficiencies on Fatigue Life of Reinforced Concrete Beams
Author(s): Nawal Kishor Banjara and K. Ramanjaneyulu
Publication: Structural Journal
Appears on pages(s): 31-44
Keywords: fatigue loading; flexure deficient; nonlinear finite element analysis; reinforced concrete beams; shear deficient; unified S-N expression
Static and fatigue behavior of three types of reinforced concrete (RC) beams—namely, control, shear-deficient (20, 40, and 60%), and flexural-deficient (30 and 50%)—are investigated. After assessing the ultimate load-carrying capacities of RC beams, experimental studies are carried out on fatigue behavior of control, 20% shear-deficient, and 30% flexural-deficient RC beams for three load ranges—20 to 65%, 20 to 75%, and 20 to 85% of respective ultimate load-carrying capacity. Further, numerical models are developed for nonlinear finite element analysis of control, shear-deficient, and flexural-deficient RC beams under monotonic and fatigue loading. Upon validation of the results of numerical simulations carried out on RC beam specimens under monotonic loading, further numerical simulations are carried out on fatigue behavior of RC beams with shear and flexural deficiencies. Based on the results of experimental and numerical investigations, a unified S-N expression which incorporates different types and levels of deficiency is also developed. This unified S-N expression will be useful to evaluate the fatigue life of reinforced concrete beam/girder with known level of shear or flexure deficiency. This will also help the engineers to plan for appropriate retrofit strategy to achieve the required fatigue life.