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

Abstract

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 prefabricated 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.

Effect of Modeling Beam-Column Joints on Performance Assessment of Columns in Non-Ductile RC Frames

“…Experimental research studies on non-seismically detailed beam-column joints conducted by Mısır and Kahraman (2013) [32] and Pantelides et al (2002) [33] are considered in this study. Geometry and reinforcing details of 2/3 scale S1 specimen [32] and full-scale Unit 4 [33] are shown in Figure 6. One reference (S1) and two exterior beam-column joints strengthened with SIFCON blocks were tested by Mısır and Kahraman (2013) [32].…”

“…Both models computed stiffness degradation as well as pinching in a good agreement with cyclic behavior of specimen (Figure 8c) and the failure mode is captured with the diagonal concrete crushing. Figure 6 -Geometry and reinforcing details of unreinforced beam-column joint for (a) S1 specimen tested by Mısır and Kahraman [32], and (b) Unit 4 tested by Pantelides et al. [33] (a) (b) During the test, first yield in longitudinal reinforcement was observed and initial significant cracking in the joint was observed at at 0.5% and 1.5% drift ratios, respectively.…”

“…Numerical simulation models for S1 specimen (a)Model A and (b) Model B Comparison of measured and computed responses for S1 specimen and (a) Model-A, and (b) Model-B and (c) lateral load-drift ratio relationships for S1 specimen[32] Pantelides et al (2002)[33] tested six exterior full-scale beam-column joints with different details of beam reinforcement and axial load ratios. For Unit-4 specimen shown inFigure 6b, average concrete strength was 31.6 MPa at the test day and beam and column longitudinal rebars with 25-and 29-mm diameters had 469 MPa and 458.5 MPa yield strengths, respectively.…”

Improving integrity of RC beam‐column joints with deficient beam rebar anchorage

“…12 The effectiveness of these strengthening methods has been verified for improving the shear resistance of exterior joints. [7][8][9][10][11][12] However, strengthening methods that are effective for improving beam rebar anchorage in exterior joints are still limited. Ghobarah and El-Amoury 13 proposed a strengthening method by carbon fiber-reinforced polymer (CFRP) sheets attached to the beam face and a strengthening method by external steel tie-rods welded to the existing beam rebar.…”

Exterior beam-column joint study with non-conventional reinforcement detailing using mechanical anchorage under reversal loading

“…Sagbas et al (2011) in their FEA Computational analysis compared with experimental test results seismically and non-seismically designed joint detailed for the effect of shear deformations. Misir & Kahraman (2013) proposed a seismic strengthening technique for non-seismically detailed beam-column joints of existing reinforced concrete buildings using pre-fabricated SIFCON composite blocks.…”