Table 1: Grade index for structural damage state.

ParameterN1 (intact)N2 (minor damage)N3 (moderate damage)N4 (severe damage)

Change of deflection (mm)a1-a2a2-a3a3-a4a4-a5
Change of strain (ε)b1-b2b2-b3b3-b4b4-b5
Predict damage values by SVMc1-c2c2-c3c3-c4c4-c5
Modal curvature rated1-d2d2-d3d3-d4d4-d5