Effectiveness of the Novel Rehabilitation Method of Seismically Damaged RC Joints Using C-FRP Ropes and Comparison with Widely Applied Method Using C-FRP Sheets—Experimental Investigation

Emmanouil Golias,George I Kalogeropoulos,Chris G Karayannis,Violetta K Kytinou,Adamantis G Zapris,Constantin E Chalioris

doi:10.3390/su13116454

Abstract

The necessity of ensuring the long-term sustainability of existing structures is rising. An important issue concerning existing reinforced concrete (RC) structures in seismically active regions is that a significant number of them lack the required earthquake-resistant capacities to meet the increased design earthquake demands. Inexpensive, fast and long-term strengthening strategies for repairing/strengthening RC structures are urgently required, not only after destructive earthquakes, but even before they occur. Retrofitting existing buildings extending their service life rather than demolishing and rebuilding new ones is the best option in terms of economic gain and environmental protection. This paper experimentally investigates the effectiveness of externally applied (i) carbon fiber-reinforced polymer (C-FRP) ropes in X-type form and (b) C-FRP sheets that are bonded on both sides of the joint area of RC beam-column joint connections. Six comparative full-scale exterior RC beam-column joint specimens were tested under reverse cyclic deformation. Two of them were control specimens, two were strengthened using C-FRP ropes (novel technique) and two were retrofitted using C-FRP sheets (widely used technique). Extensive comparisons and discussion of the test results derive new quantitative and qualitative results concerning the seismic capacity and the service life extension of the strengthened RC members using the proposed retrofitting scheme.

Highlights

Rehabilitation methods of existing infrastructures have an important role in ensuring sustainable development
Some of the experimental specimens have previously been presented by the authors in recently published studies [26,69]; the scope of the current study is to examine the effectiveness of the novel carbon fiber-reinforced polymer (C-fiber-reinforced polymer (FRP)) rope strengthening method compared to the frequently used C-FRP sheet application
The aim of this study is not to contribute to the development of design process verification of existing tools, but rather to provide practical solutions for on-site applicatools or to the verification of existing tools, but rather to provide practical solutions for tions based on experimental results about the investigated reinforcement technology of on-site applications based on experimental results about the investigated reinforcement exterior reinforced concrete (RC) frame joints and be able drawjoints practical technology of to exterior

Summary

Introduction

Rehabilitation methods of existing infrastructures have an important role in ensuring sustainable development. The term sustainability refers to structures’ ability to retain their performance at a reasonable cost and with minimal environmental impact [1]. The majority of existing structures are composed of reinforced concrete (RC), which, despite the significant environmental impact of the RC industry, is the most widely used building material worldwide [2]. The main issue concerning existing structures is that a significant number of them lack the required earthquake-resistant capacities to meet the increased design earthquake demands [3]. Considering the abovementioned, it is clear that inexpensive, fast and long-term strengthening strategies for repairing/upgrading RC structures are urgently required, after destructive earthquakes, but even before they occur [4]. Retrofitting existing buildings rather than demolishing and rebuilding new ones is the best option in terms of economic gain and environmental protection [5,6].

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Conclusion