A simplified approach to assess dynamic amplification due to accidental release of formwork traveller during the construction stages of bridges.

Construction of bridges by the cantilever method needs to consider the accidental release of the formwork traveller (ARFT) in the design phase. Often this phase is a critical situation that current regulations treat as a static analysis amplified by a dynamic factor due to the difficulty in setting up a model able to simulate the complex interaction between the formwork and the structure in the time domain during the accidental release. To overcome the simplistic approach of the regulations and to avoid the complexity of detailed ARFT modelling, in this research the release of the formwork is modelled as a simple force-time function applied to the bridge. This function has an equivalent effect on the structure as the accidental release, and it has been tuned using experimental tests on a 1:100 scale aeroelastic model of the cable-stayed Bioceanic Bridge. To test the applicability of the proposed time-function the Chilina continuous beam Bridge was also analysed. The article shows that the simplified procedure in the regulations can sometimes underestimate and overestimate dynamic amplification and, thus, a methodology is proposed to carry out the specific dynamic calculation that the regulations suggest for those cases where it is necessary. • Experimental tests on the scale model of the cable-stayed bridge. • Comparison with finite element model results. • Evaluation of the dynamic amplification factor in regulations. • Proposal of force functions for the numerical dynamic study. • Comparison of results between kinds of formwork travellers. [ABSTRACT FROM AUTHOR]