Ten-Year Study on Steel Fiber-Reinforced Concrete Beams Under Sustained Loads

Abstract

This article reports on a study of the behavior of steel fiber-reinforced concrete (SFRC) beams with different fiber contents under different sustained loads for a period of 10 years. Nine reinforced concrete beams with discrete steel fiber contents ranging from 0 to 2% were subjected to sustained flexural loading between 0.35 to 0.8 times the flexural capacity. The results showed that the addition of steel fibers to concrete is effective in containing long-term deflection and restraining crack widening. The deflections and crack widths were smaller for lower sustained loads. The modified ACI approach and effective modulus method (EMM) predict the long-term deflections very well, while the adjusted effective modulus method slightly underestimates the same. The authors conclude that, except for the permanent deformation and reduced initial stiffness due to sustained loading, the aged beams showed the same load-deflection behavior as those of the unsustained beams tested before, both in terms of strength and stiffness.