Simplified Reliability Estimation for Optimum Strengthening Ratio of 30-Year-Old Double T-Beam Railway Bridge by NSM Techniques

Table 2

Statistics of random design variables (I).

Design variable	Nominal value	Mean value	Standard deviation	Probability distribution
𝑓𝑐^′ (MPa)	41.34	46.16	1.94	Normal
𝑓fu (MPa)^a	—	2,790	85.7	Normal
𝑏 (mm)^b	1,900	𝑏+0.94	6.0	Normal
ℎ (mm)^c	1,250	ℎ−3.05	6.35	Normal
𝑑 (mm)^c	1,200	𝑑−4.70	12.70	Normal

aISO 527-3 (1997)[12], bOh et al. (1993) [13], ccross-sectional dimension of the target bridge.