ABSTRACT
Because of placement difficulties, the beamcolumn joints of RC structures can-not be fully controlled by civil engineers and it is not easy to handle this situation with care according to the design drawings. Numerous researchers have attempted to reduce the workmanship difficulties by simplifying the reinforcement lay-out in the joints. In several experimental investigations (Recommendations ACI-ASCE Committee 352, 1985; Jindal and Hasan, 1984; Craig et al., 1984; Katzensteiner et al., 1992; Filiatrault et al., 1994; Filiatrault et al., 1995), the use of steel fibre reinforced concrete (SFRC) was proposed as additional reinforcement instead of squeezing stirrups in the beam-column joints. In many of these investigations, SFRC was used in certain parts of the joints together with normally spaced transverse reinforcement instead of squeezed stirrups. The effects of various parameters on the behavior of joints have been studied experimentally, such as the type of loading, the amount of steel fibre in the concrete mix, the method of loading, and the amount of transverse and longitudinal reinforcements. These experiments showed that beam-column joint specimens with normally spaced stirrups and SFRC at the joints, displayed higher capacity for shear forces and bending moments, dissipated more energy and showed more ductile behavior than conventional ductile beam-column joints of plain concrete. All the test specimens were made with steel fibre reinforced concrete due to its higher shear strength than that of
rather well known as the first research project on shear properties of SFRC was started three decades ago (Batson et al., 1972), SFRC is only occasionally used in structural elements of buildings. In fact, steel fibre in concrete can significantly increase the shear strength of structural concrete (Lim et al., 1987, Casanova et al., 1994). It will be shown here that adding even a small amount of steel fibre can significantly improve fracture properties of concrete, thus improving ductility, overall behaviour in tension as well as an element’s performance in shear.
