Bridges

Cover of Comparative Study of Grillage Analogy and Finite Element Method for Bridge Heavy Load Assessment
Comparative Study of Grillage Analogy and Finite Element Method for Bridge Heavy Load Assessment
  • Publication no: ABC2017-142-17
  • Published: 26 April 2017

Grillage analogy is a popular method for analyzing various types of highway bridges in design offices. For load assessment of existing bridges in Australia, mainly beam line model and grillage analogy are employed to evaluate the structural integrity of bridge components due to live loadings. With majority of existing bridge networks designed per superseded design vehicles, the necessity to utilize more rigorous analysis methods to assess the load effects of bridges is indispensable. In this paper, various vehicular loading cases on grillage model of a box girder bridge with its equivalent finite element model were made. Based on the numerical analysis, it was observed that component-level load effects of two models have notable differences irrespective of vehicle speed, position and loading. However, when global-level load responses are compared, the discrepancy in outputs drops dramatically. Developed modelling ratios are practical and found to be applicable to any modelling techniques for assessment of vehicular loading both in global and component-response basis. Proposed flowchart suggested for heavy load assessment incorporates detailed and simple modelling approaches aligned with experimental data which can be used for periodic and long term monitoring of bridges. It can enhance the proper determination of bridge condition states, as any conservative estimation of bridge capacity may result in unnecessary load limitations.