Providing a model for estimating the compressive strength of square and rectangular columns confined with a variety of fibre-reinforced polymer sheets

Abstract

One of the most common ways of strengthening the columns is the confinement of the reinforced concrete columns. So far, several experiments have been conducted on concrete columns confined with fibre-reinforced polymer sheets and the results show that the use of fibre-reinforced polymer sheets increases the compressive strength of the concrete columns effectively. Different models in order to determine the compressive strength of the fibre-reinforced-polymer-confined concrete columns are provided in the previous researches. In this study, a wide range of experimental data for square and rectangular columns confined with a variety of fibre-reinforced polymer sheets has been collected. In order to increase the accuracy in the existing models, a modified model for predicting the compressive strength of square and rectangular columns confined with different fibre-reinforced sheets has been proposed by using the collected data. In the current study, the fibre-reinforced polymer strain efficiency factor and the section shape factor are composed and considered as a unique factor. Considering the fibre-reinforced polymer hoop strain concentration at the affected area including the corners area and the surrounding area of them, this factor has been adopted as a fibre-reinforced polymer averaged hoop strain factor for the whole circumference of the section. Based on the published experimental data, a comparison between the analytical results obtained with the present model and the results of the other models, shows considerably better results of the proposed model described in this study. Moreover, application of the proposed model for behaviour prediction of concrete-filled fibre-reinforced polymer tubes is evaluated in this study and the results show that the proposed model is more accurate than the other models.

Estimating the compressive strength of rectangular fiber reinforced polymer–confined columns using multilayer perceptron, radial basis function, and support vector regression methods

“…As reported in Table 4, statistical indicators related to Moodi et al 11 and Wei and Wu 9 models are the lowest values in comparison with other models. The total error of Moodi et al 11 as well as Wei and Wu 9 models are by average 42 and 25%, respectively, less than other models (Toutanji et al, 10 Pham and Hadi, 8 Harajli et al, 3 Ilki and Kumbasar, 4 and Lam and Teng 7 ). Hence, these two methods were selected as the best methods for estimating the compressive strength of square and rectangular columns confined by FRP.…”

“…To compare the performance of LM methods with two best models of previous studies (Moodi et al 11 and Wei and Wu 9 ), statistical indices of total specimens are presented in Table 6. As shown in Table 6, the differences between the statistical indicators of MLP and RBFNN methods and the models of previous studies were significant, but those of the SVR method were close to Moodi et al 11 and Wei and Wu 9 models.…”

“…To illustrate the efficiency of LM and the models of previous studies, experimental compressive strength against compressive strength resulting from MLP, RBFNN, and SVR methods and Moodi et al 11 and Wei and Wu 9 is outlined in Figures 4(A) to (E). Among LM methods and the models of previous studies, LM methods have had a higher correlation coefficient (R 2 ).…”

“…Different studies were conducted for estimating the compressive strength of columns wrapped by FRP. [3][4][5][6][7][8][9][10][11][12][13][14][15] Note that most of the proposed models were presented by limited specimens in the past.…”

New models for estimating compressive strength of concrete confined with FRP sheets in circular sections

“…Sadeghian and Fam 9 have considered the maximum confinement stress in the "confinement stiffness ratio" as well as in "strain ratio" factors to take into account the actual rupture strain and have proposed some models to estimate the compressive strength of concrete cylinders confined with FRP by analyzing 518 specimens. Moodi et al 10,11 proposed a model for estimating compressive strength of rectangular and square columns confined by FRP sheet. In their study, the effective strain coefficient of FRP was considered as function of shape section.…”