Evaluation of the Effects of Orientation and Coverage Areas of FRP Lamination Bonded with Two-Way RC Slabs – A Modular Approach

Balamurugan G,Viswanathan T S

doi:10.13189/cea.2020.080432

Abstract

Many researchers have proposed different schemes of fiber reinforced polymer (FRP) wrapping to strengthen the Reinforced Concrete (RC) slab. However, the ideal system for FRP laminations is not readily available. A modular approach for strengthening of RC slabs (especially two-way slab) needs to be developed with respect to orientations and coverage area of FRP sheets in order to figure out the effective strengthening system. This paper describes the experimental study carried out to explore the effects of fiber reinforced polymers in different orientation and coverage areas to strengthen the structural members. Three systems of laminates have been used to strengthen the RC slabs using two types of fibers, namely carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composite. The systems are classified with respect to the orientation of FRP sheets such as edge, corner and center wrapping. Each system has three proportions of FRP coverage area in the order of 25%, 35%, and 45%. A set of fifty-four slabs were fabricated and tested at the rate of three specimens for each variant. The performance of the flexural strength of two-way RC slabs with different strengthening systems has been evaluated and compared. It shows that all the systems of strengthening are effectively enhancing the flexural strength of two-way RC slabs. The extent depends on the system orientation and coverage area of the FRP sheet. The higher-order performance is noticed when the FRP lamination has higher contact with the slab area and with closer proximity to the loaded area.

Highlights

Structures, especially RC – Reinforced Concrete structural members are always facing new challenges during their life span, in terms of loading, structural behavior and durability
This paper aims to study the effectiveness of orientation with a satisfactory coverage area of fiber-reinforced polymers (FRP) on two-way RC slabs and corresponding performance factors such as flexural strength and mode of failure, ductility, and stiffness
The maximum ductility is noticed in center wrapping, which is about 30% higher compared to the control slab

Summary

Introduction

Structures, especially RC – Reinforced Concrete structural members are always facing new challenges during their life span, in terms of loading, structural behavior and durability. The readily available strengthening techniques based on lamination with fiber-reinforced polymers (FRP) are enhancing the strength of reinforced concrete slabs (Al-Bayati, et al 2018; Al-Saadi et al 2016; Al-Sulayvani et al 2015; Bonacci et al 2001; Delnavaz et al 2015). The existing techniques or methods do not have specific information and guidelines with respect to the effective coverage area and orientation of FRP composites on the RC slabs, and their performance factors are not explored fully. Gherdaoui et al (2018) used the following orientations of the CFRP laminates used to strengthen the slabs such as 0o, 45o, 00/900 and 450/135o. As of the available literature reviews, it is clear that the existing strengthening systems need to be developed further for RC slab with the concern on the effective orientation and sufficient coverage area of FRPs

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Conclusion