Seismic vulnerability of existing R.C. buildings: A simplified numerical model to analyse the influence of the beam-column joints collapse

Abstract

In order to evaluate seismic vulnerability of existing reinforced concrete buildings, a simplified approach is proposed to take into account the beam-column joints shear collapse. This collapse is described by a link element which is introduced between column and beam. To develop and verify this element, several comparisons have been performed with experimental results of laboratory test and numerical results obtained by a two-dimensional finite element model specifically carried out for this check. The link element uses a tri-linear moment-rotation law, compatible with standard Italian and European codes, whose features can be estimated by limited structural and geometrical information, which is a typical situation on older existing structures, and by standard code recommendations. In order to give a preliminary evaluation of the seismic capacity for existing R.C. frames, taking into account the beam-column joints behaviour, this link element has been introduced in a one-dimensional model of bearing structure of the Unit N.1 of the Santa Maria Annunziata Hospital in Florence (Italy) and pushover analyses have been carried out.

The development of a dynamic fracture propagation model for FRP-strengthened beam-column joints

“…and stresses in the and -FRP reinforcement, respectively. Ultimate force of beam-column joint is used which has been implemented using the finite element method by Borghini et al [35] to control collapse. Tension stress and compression stress are [35]:…”

A Case Study on Structural Failure of Reinforced Concrete Beam-Column Joint After the First Significant Earthquake Impact in Malaysia

“…Areas of low to moderate seismicity have been discovered to be more prone to damages than areas of high seismicity [1]. Throughout the world, a majority of old reinforced concrete (RC) building structures are designed and built only for gravitational load without weighing in active seismic areas [2]. Recently, the Malaysian construction industry has begun adhering to the design guideline imposed by the British Standards [3].…”

Simplified assessment of the need for the explicit model of RC beam‐column joints instead of the rigid model

“…However, regardless of the full or partial strength nature of RCBC joints, the influence of their flexibility on the structure overall quasi‐static behaviour should not be neglected—not to mention their influence on progressive collapse or seismic behaviour, which are beyond the scope of this paper. This is recognized by current technical specifications (e.g., ), which require the inclusion of the effect of beam‐column joints deformation in structural models.…”

“…[1][2][3][4] Consequently, current technical specifications require that the strength of RCBC joints is larger than that of the adjacent columns and beams (full strength joints), that is, a joint must not fail before its adjacent elements 5 -in seismic design this is accomplished through the capacity design principles, which classify RCBC joints as brittle components. [6][7][8] However, regardless of the full or partial strength nature of RCBC joints, the influence of their flexibility on the structure overall quasi-static behaviour should not be neglected 9 -not to mention their influence on progressive collapse 10,11 or seismic behaviour, [12][13][14] which are beyond the scope of this paper. This is recognized by current technical specifications (e.g., 5,15 ), which require the inclusion of the effect of beam-column joints deformation in structural models.…”