Diagnosis of and remedy for imperfection sensitivity of arch bridges

Abstract

AbstractUnless the hangers of arch bridges are sufficiently stiff, such bridges are imperfection sensitive [1]. Increasing the stiffness of the hangers, such structures eventually become imperfection insensitive. The mathematical definition of imperfection insensitivity follows from a series expansion of the dimensionless load parameter Δλ(κ, η), relative to the stability limit λ = λS, given as [2] Δλ(κ, η) = λ1(κ)η + λ2(κ)η2 + λ3(κ)η3 + O(η4), where λ1, λ2, … are coefficients depending on the stiffness of the hangers representing the design parameter κ and η is a path parameter describing the postbuckling path.A necessary condition for imperfection insensitivity is [3] λ1(κ) = 0 ∀κ. If, for a specific value κ of κ, also λ2(κ=κ) > 0, then the structure is imperfection insensitive for κ=κ.It will be shown numerically that the increase of the stiffness of the hangers is the remedy addressed in the title of the paper. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)