Extending the Fatigue Life of Steel Truss Bridges with Tuned Mass Damper Systems

Table 1

Values of damping to be assumed for design purposes.

Bridge type	Lower limit of percentage of critical damping, ζ (%)
	Span L < 20 m	Span L ≥ 20 m
Steel and composite	ζ = 0.5 + 0.125 (20-L)	ζ = 0.5
Prestressed concrete	ζ = 1.0 + 0.07 (20-L)	ζ = 1.0
Filler beam and reinforced concrete	ζ = 1.5 + 0.07 (20-L)	ζ = 1.5