Seismic strengthening of existing RC beam‐column joints by wing walls

Li, Yuebing; Sanada, Yasushi

doi:10.1002/eqe.2890

Cited by 16 publications

(27 citation statements)

References 3 publications

(8 reference statements)

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“…This result verifies that Equation (19) provides a conservative estimation of the tensile capacity of anchors, assuming steel failure. Therefore, a minimum embedment length of 10d a is recommended for application in strengthening design to develop ductile behavior by yielding of anchors.…”

Section: F I G U R E 1 6 Setup Of Pullout Testsupporting

confidence: 78%

“…The design procedure proposed in the previous study 19 was effective to ensure formation of a beam yielding mechanism in the strengthened specimen. The specimen with deformed bar and straight anchorage at the end, J1, failed by anchorage failure (pullout of beam longitudinal bars) in the negative loading direction, while joint shear failure was observed in the positive loading direction.…”

Section: Discussionmentioning

confidence: 99%

“…The moment diagram of the specimens under seismic loads is shown in Figure , assuming that the inflections are at the midpoint of the columns and beam. The ultimate strength of the frame M u representing the joint node moment and the failure mode is determined by Equation , which was proposed in the previous study

M_{u} = \min . ([],,, (_{n} M_{italiccu1} +_{n} M_{italiccu2}), _{n} M_{bu}, M_{italicju})

where n M cu1 / n M cu2 is the nodal moment at the joint when the upper/bottom column yields at the critical section (N·mm), n M bu is the nodal moment at the joint when the beam yields at the critical section (N·mm), and M ju is the moment capacity of the joint (N·mm).…”

Section: Seismic Performance Evaluation Of Typical Exterior Beam‐columentioning

confidence: 99%

“…In consideration of the economic situation and technical level of developing countries, strengthening of beam‐column joints by concrete jacketing, local enlargement of joint, or installing additional structural elements (ie, RC wing walls), which use conventional materials such as concrete and reinforcement, are likely to be practical solution. However, these strengthening methods were developed for improving shear resistance of the joints, not for improving anchorage of beam rebar in joint.…”

Section: Introductionmentioning

confidence: 99%

“…However, these strengthening methods were developed for improving shear resistance of the joints, not for improving anchorage of beam rebar in joint. In a previous study, a strengthening method by installing RC wing walls has been proposed and validated to upgrade the exterior joints without shear reinforcement. In this study, the strengthening method by installing wing walls is proposed to upgrade exterior joints with substandard anchorage of beam longitudinal rebar.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

Wardi

Sanada

Saha

et al. 2020

Earthq Engng Struct Dyn

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In recent earthquakes in developing countries, severe damage was observed on reinforced concrete buildings. This study focuses on exterior beamcolumn joints with substandard beam rebar anchorage and seismic strengthening by installing wing walls. First, a series of experiments was conducted to investigate the seismic behavior of exterior joints with substandard beam rebar anchorage representing typical Bangladeshi buildings.Two 0.7-scaled exterior joint specimens were tested, and these specimens showed beam rebar anchorage failure and/or joint shear failure. Prior to strengthening of the joint, a series of pullout tests was conducted on postinstalled bonded anchors in low-strength concrete for strengthening design.Then, an experiment was performed to apply the strengthening method by wing walls to one of the exterior joint specimens to improve the integrity, and this method was intended to prevent the failure of beam rebar anchorage. The strengthening method is proposed to extend the development length of beam longitudinal bars by considering the embedment length along the wing walls. The test results verified the effectiveness and applicability of the proposed strengthening method to upgrade exterior RC beamcolumn joints with deficient beam rebar anchorage. K E Y W O R D Sanchorage failure, developing country, low-strength concrete, reinforced concrete, seismic strengthening, substandard structure

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Section: F I G U R E 1 6 Setup Of Pullout Testsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

M_{u} = \min . ([],,, (_{n} M_{italiccu1} +_{n} M_{italiccu2}), _{n} M_{bu}, M_{italicju})

Section: Seismic Performance Evaluation Of Typical Exterior Beam‐columentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Wardi

Sanada

Saha

et al. 2020

Earthq Engng Struct Dyn

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Strengthening seismically vulnerable reinforced concrete flat plate‐column connections by installing wing walls

Samdani

Takahashi

Yoon

et al. 2021

Japan Architectural Review

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This study emphasizes a new strengthening scheme for seismically vulnerable flat plate-column connections in existing structures. An experimental investigation on a series of three half-scaled interior plate-column connections was conducted to explore the effectiveness of the proposed seismic strengthening method using postinstalled RC wing walls and to analyze the punching shear capacity of the connections. This study focuses on typical existing flat plate structures constructed using low-strength concrete in Bangladesh. Two of the three specimens had wing walls employed in two principal directions, that is, along the loading direction and orthogonal direction, while another specimen was tested without wing walls and served as a control specimen for comparisons between the cases with and without strengthening. Static cyclic vertical displacements with increasing amplitude were applied to the ends of the slabs to represent interstory drift under seismic action. Both strengthened specimens showed higher resistance to punching shear failure. Thus, the test results experimentally verified that installing RC wing walls is a feasible method to upgrade flat plate-column connections, including those constructed using low-strength concrete, to prevent collapse under seismic action.

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Reinforced concrete beam‐columns anchored with headed bars subjected to reversed cyclic loading: Experimental and numerical investigation

Chourasia

Singhal

Parashar

et al. 2023

Structural Concrete

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Past seismic events have shown poor performance of reinforced concrete (RC) moment resisting frames, due to failure of beam-column joints, attributed to insufficient anchorage and poor workmanship. Inadequate development length in beam-column joints may lead to joint strength deterioration due to detailing constraints and site errors. Alternatively, headed bars have potential to replace conventional anchorage system of development length in beamcolumn joint. The paper deals with extensive experimental and numerical program conducted on RC beam-column joints with plain and deformed (grooved and ribbed) headed bars and compared with the specimens with conventional development length. Effect of steel fibers on strength of RC beam-column joints is also investigated. The test specimens of beam-column joints were subjected to displacement-controlled reversed cyclic loading and structural behavior was assessed in terms of failure mode, load carrying capacity, stiffness, drift, ductility, and energy dissipation. The strength parameters of headed bar specimens were well comparable to that of conventional specimens. Groovedheaded and ribbed-headed bar specimens exhibited superior load resistance as compared with plain-headed bar specimens. Numerical analysis was carried out, whose results were in agreement with the experimental results, thus demonstrating the efficacy of headed bars as mechanical anchorage system for RC beam-column joints.

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Seismic strengthening of existing RC beam‐column joints by wing walls

Cited by 16 publications

References 3 publications

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

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

Strengthening seismically vulnerable reinforced concrete flat plate‐column connections by installing wing walls

Reinforced concrete beam‐columns anchored with headed bars subjected to reversed cyclic loading: Experimental and numerical investigation

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