11.3 Bending stiffness 1l.3.1 Method of effective moment of inertia(有效惯性矩法) 1)Pre-cracking stage Ec N.A. Xo As h ho-Xo a (n-1)As Transformed section:4=bh+(n-1)4.11.3 Bending stiffness 11.3.1 Method of effective moment of inertia （有效惯性矩法） As b h (n-1)As N.A. x0 a h0-x0 εc εs 1) Pre-cracking stage A bh n A s ( 1) Transformed section: 0   