Quasi-static tests on RC building columns strengthened with CFRP

Abstract

To explore the possibilities and benefits of using CFRP (Carbon Fibre Reinforced Polymers) in strengthening RC building columns, quasi-static tests (compression and bending) were carried out at the Institute of Earthquake Engineering and Engineering Seismology - IZIIS, Skopje by variation of concrete class, reinforcement percentage and by using various strengthening technologies. Some recommendations and outcomes regarding the approach, technology and conclusions drawn from practical application of these materials, are given. Based on the analysis of values obtained from nonlinear static and nonlinear time history analyses, it can be concluded that the ductility capacity for displacement of model strengthened with CFRP is greater by 60 %, while its strength capacity is greater by 7.7 % when compared to the values obtained for the model without CFRP. It can generally be concluded that CFRP systems are a very practical tool for strengthening and retrofitting concrete structures, as they can extensively improve flexural strengthening, shear strengthening, column confinement, and ductility.

Software development for retrofitting columns with FRP composites: A case study

“…Provedena su kvazistatička ispitivanja kako bi se procijenila učinkovitost materijala. Nakon analize rezultata dobivenih nelinearnom statičkom i nelinearnom analizom vremenskog zapisa, može se zaključiti da model pojačan CFRP-om ima 60 % veći kapacitet duktilnosti izražen preko pomaka i 7,7 % veću nosivost od modela bez CFRP-a [41]. Cilj istraživanja Demira i sur.…”

“…Proračun pojačanja pomoću FRP-a materijala izveden je pomoću C++ računalne aplikacije zasnovane na jeziku koju su razvili autori primjenom računalnog programa Microsoft ® Visual Studio [45] (slika 7.). Pomoću navedenog programa napravljeni su proračuni za stupove s nedovoljnom nosivošću poprečnog presjeka prema pravilima navedenima u TSC-2018 [41]. Izračunana je potrebna količina volumetrijskog omjera vlaknastih polimera, tlačna čvrstoća ovijenog betona (f cc ) te bočni tlak koji daje FRP (f 1 ).…”

Performance of CFRP-confined concrete cylinder specimens - laboratory study

“…An original research program involving experimental investigations on a series of two elements-models (columns) was defined for the needs of this investigations in order to contribute to the definition of the joint behaviour of concrete, reinforcement, and CFRP materials in the nonlinear range, and to develop a methodology and criteria for the application of these materials in seismically active regions, [32]. The main objective of the research programme was to define the strength and deformability of the elements constructed of innovative materials, as a function of a number of selected parameters that were varied in the course of the experiments.…”