Seismic Performance of Substandard RC Columns Retrofitted with Sprayed GFRM

Nima Kian*, Ugur Demir, Cem Demir, Muhammed Marasli, Alper Ilki

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

There is a myriad amount of substandard reinforced concrete (RC) buildings in developing countries that do not comply with the requirements and instructions of the current building design codes. In particular, columns in these substandard buildings demonstrate unsatisfactory and undesired behavior against lateral loads, mainly due to low concrete compressive strength and poor reinforcement detailing. The problem is exacerbated when the axial load ratio (ratio of applied axial load to the axial load capacity) and/or the shear ratio (ratio of shear force corresponding to moment capacity (Ve) to the shear capacity (Vr)) is/are high, leading to brittle failure modes. In this study, three full-scale substandard RC columns subjected to high axial load ratio of 0.75 were tested under constant axial load combined with reversed cyclic lateral displacements. Shear ratio (Ve/Vr) of the substandard columns were 0.75 and 0.82 according to ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and (Turkish Building Earthquake Code (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), respectively. According to the TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey), columns had a high Ve/(fctmbd) ratio of 1.12, where, fctm, b, and d are the direct tensile strength of concrete, width of the cross-section, and effective depth of the section. The ratio of transverse reinforcement to minimum required transverse reinforcement according to the ACI 318-19 (ACI 318 (2019) Building Code Requirements for Structural Concrete. American Concrete Institute, Farmington Hills, MI, USA) and TBEC (Turkish Building Earthquake Code (TBEC) (2018) Disaster & Emergency Management Authority, Ankara, Turkey) was 0.19 and 0.77, respectively. Two of the columns were retrofitted with an innovative, cost-effective, and easily-applicable strengthening method, through external jacketing with sprayed glass fiber reinforced mortar (GFRM) of different characteristics. The remaining column was tested as the reference specimen to evaluate the efficiency of the strengthening method. The test results demonstrated the extremely poor performance of the reference substandard column as well as the remarkable lateral load capacity and ductility improvement provided by the adopted novel strengthening approach.

Original languageEnglish
Title of host publication10th International Conference on FRP Composites in Civil Engineering - Proceedings of CICE 2020/2021
EditorsAlper Ilki, Medine Ispir, Pinar Inci
PublisherSpringer Science and Business Media Deutschland GmbH
Pages1317-1328
Number of pages12
ISBN (Print)9783030881658
DOIs
Publication statusPublished - 2022
Event10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2021 - Virtual, Online
Duration: 8 Dec 202110 Dec 2021

Publication series

NameLecture Notes in Civil Engineering
Volume198 LNCE
ISSN (Print)2366-2557
ISSN (Electronic)2366-2565

Conference

Conference10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering, CICE 2021
CityVirtual, Online
Period8/12/2110/12/21

Bibliographical note

Publisher Copyright:
© 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Funding

Acknowledgments. This research was granted in the scope of the bilateral collaboration between the research councils of Turkey (TUBITAK) and the United Kingdom (RCUK) under the grant number 216M379. The authors are most thankful to the Fibrobeton company for their continuous support from the construction phase of the specimens to the testing stage. The contributions of Furkan Narlitepe, Merve Nur Demir, Alihan Baltaci, Muhsin Can Luleci, Bilal Sari, Safiye Gundogan, Erkan Tore and summer trainees are gratefully acknowledged.

FundersFunder number
Research Councils UK216M379

    Keywords

    • Basalt mesh
    • GFRM
    • Reinforced concrete column
    • Seismic
    • Strengthening

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