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Ultimate stress and strain models for AFRP confined concrete columns with inclined fiber orientation

•   Mr. Alireza Arabshahi ,  Ferdowsi University of Mashad ,   
•   Mr. Nima Gharaei Moghaddam ,  ferdosi unversity of mashhad ,   
•   Dr. Mohammadreza Tavakkolizadeh ,  Ferdowsi Univeristy of Mashhad ,   

Major Topic: Concrete Structures|سازه های بتنی

Abstract

Various stress and strain models are proposed for AFRP confined concrete columns. Almost all of these relations are developed by assuming fiber angles perpendicular to the column axis. Therefore, application of these relation to predict ultimate confined stress and strain of columns confined with FRPs having incline fibers results in inaccurate estimations. Accordingly, in this paper, modification factors are proposed to make the available stress and strain models applicable for the FRP confinement with inclined fiber orientation. For this purpose, a database of experimental tests on such columns are collected from the previous studies. The part of the collected database is used to calibrate some of the best performing confined stress and strain models utilizing nonlinear regression techniques and an evolutionary optimization algorithm called Multi-Expression Programming (MEP). Then the remaining experimental results are used to evaluate accuracy of the proposed relations. The attained results indicate good accuracy of the suggested relations in estimating ultimate stress and strain of FRP confined concrete columns with inclined fiber angle.

Keywords

AFRP confinement; Ultimate confined stress and strain; Inclined fiber orientation; MEP