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Finite Element Analysis of Structural Steel Impact Damage and Heat Straightening

Abstract

Damage to overpassing bridges commonly occurs due to corrosion, fatigue, and vehicle impact. Unlike corrosion and fatigue, where damage develops slowly over time, impact damage due to over‐height vehicles is sudden and unpredictable. This paper briefly introduces the heat straightening process and reviews cases where heat straightening for bridge remediation after vehicle impact was found to be cost‐effective. In addition, this paper presents several Finite Element Analysis (FEA) studies performed to determine the required level of complexity to model structural steel impact damage and heat straightening for the purpose of structural assessment and remediation design. The impact studies focus on comparing the residual stresses, strains, and displacements for two common methods of analysis, i.e.: quasi‐static and dynamic analysis. The heating process for heat straightening repairs is simulated using a simplified modelling approach and the results are compared to experimental plastic rotation data at different heating temperatures. Heat straightening parameters such as heating time, support conditions, and heating method are then discussed. With the proposed method for modelling the heating process, the motion and heat from the torch are represented with multiple segments and heating convection coefficients. The results from the simplified FEA for impact and heat straightening are used to discuss the validity of the modelling techniques and assumptions used. Further work is needed to apply the investigated analysis methods to full‐scale bridge girders. Experimental study is also recommended to obtain material parameters and further validate the analysis methods.

Conference Paper Details

Session title:
Structures
Author(s):
Fong, N.
Gracie, R.
Walbridge, S.
Topics:
Structures
Year:
2014