Seismic Performance Evaluation and Strengthening of RC Frames with Substandard Beam-Column Joint: Lessons Learned from the 2013 Bohol Earthquake

Li, Yuebing; Sanada, Yasushi; Takahashi, Susumu; Maekawa, Koki; Choi, Ho; Matsukawa, Kazuto

doi:10.1142/s1793431116400078

Cited by 6 publications

(4 citation statements)

References 1 publication

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“…However, this assumption may mislead the analysis results in the case of substandard beam-column joints, because the failure of the joint may occur as confirmed in the literature of experimental studies (e.g. [1], [2], [10]- [12]) and an experimental study by one of the authors [3].…”

Section: Introductionmentioning

confidence: 99%

Pushover Analysis of Rc Frames With Substandard Beam-Column Joints

2023

GEOMATE

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Recent earthquakes in developing countries showed that the failure of substandard beamcolumn joints often contributes to heavy damage or collapse of reinforced concrete (RC) buildings. Static nonlinear pushover analysis is one of the methods to evaluate the seismic capacity of RC frames/buildings. However, the pushover analysis commonly neglects the failure at beam-column joints because of the complex behavior. In this study, a nonlinear pushover analysis procedure considering the failure of exterior beamcolumn joints without shear reinforcement is presented. Specifically, the performance limit is assumed as a point at the failure of beam-column joints from the literature of experimental study and a simplified backbone of joint shear stress-strain response. The proposed analysis procedure was applied to one RC frame with substandard beam-column joints representing a collapsed building due to a recent earthquake in Indonesia. The proposed analysis procedure was applicable to estimate the seismic capacity of RC frames considering the failure of exterior beam-column joints.

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Section: Introductionmentioning

confidence: 99%

Pushover Analysis of Rc Frames With Substandard Beam-Column Joints

2023

GEOMATE

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“…[1][2][3] Additionally, such poorly detailed joints still exist in newly constructed buildings in an area affected by a recent earthquake, 1 as observed in a field survey by two of the authors. Recent earthquakes in developing countries have revealed that severe damage or collapse of RC buildings is often caused by poor performance of the beam-column joints with substandard detailing.…”

Section: Introductionmentioning

confidence: 99%

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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“…Many buildings exist in developing countries potentially contain improper structural details which do not adequately meet requirements and/or recommendations according to the design guidelines [1][2][3][4][5] . As a result, such buildings in several developing countries have suffered from severe damage under sudden earthquakes.…”

mentioning

confidence: 99%

“…Beam-column joints are a critical link in modern moment-resisting RC structures. Recent seismic events [3][4][5] globally have highlighted the vulnerability of the beam-column joints, often resulting in severe damage. In developing countries like Bangladesh, the beam-column joints are even more susceptible to damage/total failure due to the following practical background.…”

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confidence: 99%

Accurate measurement of the bond stress between rebar and concrete in reinforced concrete using FBG sensing technology

Ahmed,

Matsumoto,

Yoon

et al. 2024

Sci Rep

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Recent earthquakes in several developing countries have shown that reinforced concrete (RC) buildings with improper structural detailing experience severe damage under seismic motions. Using low-quality construction materials such as brick aggregates, resulting in low-strength concrete, significantly impacts the bond between rebar and concrete. Accurate evaluation of the bond performance of such low-strength concrete is one of the key issues for seismic safety assessment of RC buildings, especially in Bangladesh; thus, the bond performance is usually evaluated through laboratory tests. However, conventional measurements of bond stress based on rebar strains measured by electrical resistance strain gauges are likely to negatively impact the bond behavior/performance because of the reduced total contact area between rebar and concrete as well as the changing rebar surface boundary conditions. Under the above social and academic backgrounds, in this study, a new measurement technique that applies fiber Bragg grating (FBG) sensors embedded in optical fiber to rebar strain measurements is developed, and its effectiveness is investigated to realize more accurate measurements of the bond stress between rebar and concrete. Two 70% scaled RC beam-column joint specimens in which the beam rebar was anchored in a straight manner were constructed with identical detailing, except for the beam rebar strain measuring methods. The specimens were then subjected to cyclic lateral loading until failure. By comparing the experimental data acquired by the above two different devices (the FBG sensors and conventional strain gauges), it was found that the experimental bond strength on the beam rebar based on the strain data measured by the FBG sensors was much higher than that from the data measured using conventional strain gauges. Which negatively impacted the test data on the beam-column joint’s capacity in the specimen applied the conventional measuring method, indicating the necessity of the presented method not only for accurate evaluation of the bond stress between rebar and concrete but also for seismic safety assessments of RC buildings.

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Seismic Performance Evaluation and Strengthening of RC Frames with Substandard Beam-Column Joint: Lessons Learned from the 2013 Bohol Earthquake

Cited by 6 publications

References 1 publication

Pushover Analysis of Rc Frames With Substandard Beam-Column Joints

Pushover Analysis of Rc Frames With Substandard Beam-Column Joints

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

Accurate measurement of the bond stress between rebar and concrete in reinforced concrete using FBG sensing technology

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