Cyclic Performance of Beam-Column Joints with Extended Column Fixed at Base: Part I - Experimental Investigation

http://www.icevirtuallibrary.com/content/journals “Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.”The seismic performance of a non-seismically detailed reinforced concrete (RC) beam–column joint with column pinned and fixed at the base is experimentally investigated in this paper. Six half-scale RC beam–column specimens were tested to study the effect of inflection point on the cyclic behaviour of beam–column sub-assemblages. The specimens were separated into two groups. The shape of specimens in the first group was cruciform; the size of the column in those specimens was varied while the size of beam was kept nearly constant. The dimensions and reinforcing detail of specimens in the second group were identical to those in the first one except that the column was extended to the footing and fixed at the base. The main variable in this study was the relative stiffness between beam and column, which affects the position of the inflection point. The test results demonstrated a significant effect of inflection point position on the load capacity, joint shear stress and failure mode

Cyclic Performance of Beam-Column Joints with Extended Column Fixed at Base: Part I - Experimental Investigation

http://www.icevirtuallibrary.com/content/journals “Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees.”The seismic performance of a non-seismically detailed reinforced concrete (RC) beam–column joint with column pinned and fixed at the base is experimentally investigated in this paper. Six half-scale RC beam–column specimens were tested to study the effect of inflection point on the cyclic behaviour of beam–column sub-assemblages. The specimens were separated into two groups. The shape of specimens in the first group was cruciform; the size of the column in those specimens was varied while the size of beam was kept nearly constant. The dimensions and reinforcing detail of specimens in the second group were identical to those in the first one except that the column was extended to the footing and fixed at the base. The main variable in this study was the relative stiffness between beam and column, which affects the position of the inflection point. The test results demonstrated a significant effect of inflection point position on the load capacity, joint shear stress and failure mode

Strengthening of non-seismically detailed reinforced concrete beam–column joints using SIFCON blocks

This article aims to propose a novel seismic strengthening technique for non-seismically detailed beam column joints of existing reinforced concrete buildings, typical of the pre-1975 construction practice in Turkey. The technique is based on mounting pre-fabricated SIFCON composite corner and plate blocks on joints with anchorage rods. For the experimental part three 2/3 scale exterior beam column joint specimens were tested under quasi-static cyclic loading. One of them was a control specimen with non-seismic details, and the remaining two with the same design properties were strengthened with composite blocks with different thickness and anchorage details. Results showed that the control specimen showed brittle shear failure at low drift levels, whereas in the strengthened specimens, plastic hinge formation moved away from column face allowing specimens to fail in flexure. The proposed technique greatly improved lateral strength, stiffness, energy dissipation, and ductility

Concrete Columns Confined with Large Rupture Strain Composites: An Emerging Field

2020, Springer Nature Singapore Pte Ltd. Large rupture strain (LRS) fibre-reinforced polymer (FRP) composites are emerging as a competitive solution for the seismic retrofitting of reinforced concrete (RC) columns. Research on the confinement of concrete with FRP to date has primarily been focused on traditional FRP composites exhibiting ultimate tensile strains generally less than 3%. Such composites are usually made from carbon, glass or aramid fibres. For this reason, existing knowledge of FRP confinement needs to be assessed with the use of LRS FRP composites that possess tensile strain capacities well in excess of traditional FRP materials. Initially, this paper introduces large rupture strain fibres. Then, a summary of existing research on the compressive behavior of LRS FRP-confined concrete columns is provided. The general form of the compressive stress-strain relationship of such confined concrete is bilinear and similar to that of circular columns confined with traditional FRP composites. However, similar to square and rectangular columns insufficiently confined with traditional FRPs, square and rectangular LRS FRP-confined columns exhibit a strength softening region before the FRP activates. It is expected that if the stiffness of LRS FRP confinement materials is increased, then a more traditional bilinear behavior could be exhibited. Finally, recommendations for future research are provided