ABSTRACT
In order to improve performance of highway bridges, design should be based on live load models which reproduce the effects of actual vehicles. There is a need to update the live loads for highway bridges in the Brazilian design codes, which were not defined for this purpose.
From the analyses of five data sources, a comprehensive database was developed and used to simulate traffic on typical bridges of the Brazilian highways (reinforced concrete Π cross-section structures), considering spans up to 40 m in free flow (the governing situation in terms of effects on small-span bridges, with dynamic amplification), aiming the extreme distributions of static effects.
To evaluate this, dynamic analyses for these bridges were performed, considering the vehicle-pavement-structure interaction and, provisionally, the motion equations of a 5-axle truck. Target values are obtained from the product of the characteristic static effects by the corresponding dynamic amplification factor (DAF).
It is demonstrated that the Brazilian design codes do not reproduce the effects of the real traffic and in many cases may be non-conservative (see Fig. 1). Comparison in terms of negative bending moment between the target values and the effects generated by NBR 7188 Brazilian codes’ load models for wide deck (WD) bridges with cantilever beam. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315207681/cd556cd4-4dcf-4efe-8e29-56fc67b8bfbd/content/fig231_1.tif"/>
