PSI - Issue 37

Jamal A. Abdalla et al. / Procedia Structural Integrity 37 (2022) 660–667 Abdalla et al./ Structural Integrity Procedia 00 (2019) 000 – 000

664

5

(a) 0S0W

(b) 4S2W

1.5

1.5

0.5 Capacity Ratio (P R ) 1

0.5 Capacity Ratio (P R ) 1

-2.248E

P R = P u /P o = 1.368(e)

-2.485E

R

P R = P u /P o = 0.940(e)

R

R 2 = 0.999

R 2 = 0.997

0 0.2 0.4 0.6 0.8 1 0

0 0.2 0.4 0.6 0.8 1 0

Eccentrity Ratio (E R )

Eccentrity Ratio (E R )

(c) 4S4W

(d) 4S8W

1.5

1.5

0.5 Capacity Ratio (P R ) 1

0.5 Capacity Ratio (P R ) 1

-2.304E

-2.2046E

P R = P u /P o = 1.416(e)

P R = P u /P o = 1.362(e)

R

R

R 2 = 0.996

R 2 = 0.992

0 0.2 0.4 0.6 0.8 1 0

0 0.2 0.4 0.6 0.8 1 0

Eccentrity Ratio (E R )

Eccentrity Ratio (E R )

Fig. 2. Effect of eccentricity ratio in uniaxial capacity of columns

4.2. Linear Models In similar fashion to the nonlinear models, the relation between eccentricity ratio and axial capacity of eccentric loaded columns were developed using linear models for non-strengthened and strengthened specimens. The effect of eccentricity ratio on the axial load capacity ratio is shown in Fig. 4, where the normalized axial load capacity P R ( P R = P u /P o ) versus the nominal eccentricity ratio ( E R ) is presented. These models display linear relationship curves between the eccentricity ratio E R and the predicted axial load capacity ratio P R of the specimens where P u is the predicted ultimate load and P o is the axial load capacity of the concentrically loaded column without NSM-CFRP strips and without CFRP wraps (0S0W). The behavior of all specimens follows the same pattern, where the axial loading capacity is highly dependent on the eccentricity ratio, however for strengthened specimens the decrease in axial load capacity ratio with respect to eccentricity ratio is steeper than the unstrengthened ones. It is also observed that, the increase in the number of CFRP wraps induces further reduction in the axial load capacity as well. The correlation coefficient for the prediction models ranges between 0.89-0.99 for all cases. Furthermore, the developed models are capable of reasonably predicting the axial load capacity of uniaxially loaded columns strengthened with NSM-CFRP strips and CFRP wraps, reasonably. A summary of other statistical performance measures in terms of R 2 , MAPE , RMSE, and NMSE are listed in Table 4.