6533b856fe1ef96bd12b2621

RESEARCH PRODUCT

Load-carrying capacity of axially-loaded RC members with circular openings

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Abstract Core drilling is today one of the most used technique among the group of partially destructive testing methods in reinforced concrete (RC) members. Even if the engineering practice provided to extract cores only in beams, taking samples from columns could be often necessary. In this case, the presence of the hole introduced a geometrical discontinuity in the member, creating a disturbed region. Consequently, compressive stresses will disperse in lateral direction as they have to avoid the drilled area. A bursting tensile force will develop, in orthogonal direction to the column axis, and if no sufficient reinforcement was arranged, a vertical crack will form, leading to the concrete splitting. Such a failure mode was related to the tensile strength of concrete and consequently it could be weak and dangerous. In the last years a very poor amount of works was carried out on the behavior of drilled compressive members. Among them, most of studies investigated from an experimental point of view. In this paper, an analytical model is presented able to predict the load-carrying capacity of RC columns with core holes. The model is constituted by two parts: the first part is based on a continuum approach and it allows to find the position and the intensity of the bursting (or splitting) force; the second part is an equilibrium-based model able to design the reinforcement. Results obtained analytically are compared with those obtained by non-linear F.E. analysis and with experimental data available in the literature. Results are discussed and design considerations are made.