Repairing reinforced concrete beams by ferrocement

Abstract

This paper presents a proposed method for repairing reinforced concrete beams using ferrocement laminates as a viable alternative to steel plates which are directly glued to the cracked tension face ofthe beam by epoxy resins. The results of both experimental and analytical investigations to examine the effectiveness of this method are reported and discussed including strength, deflection, and cracking characteristics of the repaired specimens. Twenty seven reinforced concrete beams were tested over simply supported one meter span. Each specimen was first loaded with a central line load till collapse or up to (85%) ofthe ultimate load of the control specimen. After unloading, the damaged beam specimens were repaired by either one layer at the tension face, two layers at the tension face, or U-shaped layer around the beam cross-section. The finite element technique was used to analytically investigate the effectiveness of the proposed repair method. The 3-dimensional feature available in the commercial analysis package (ANSYS 5.1) was used to model all test specimens. The model accommodates the material non-linearities, cracking and crushing of concrete and yielding ofthe steel. The analytical results compared well with the experimental ones which served as a verification for the analytical model. Consequently, the analytical model was used to investigate additional parameters to complement the experimental investigation. The analytical and experimental results of the repaired beams demonstrated that irrespective of the pre-loading level or the repair scheme, better cracking behavior for all test specimens could be achieved compared to their original behavior. Under short term loading conditions, all repaired specimens restored more than their original ultimate strengths. It was found that the ultimate strength ofthe repaired specimens is affected by the level of damage sustained prior to repairing. The ductility ratio and energy absorption properties were also improved by this method of repair.