Direct displacement-based assessment with nonlinear soil–structure interaction for multi-span reinforced concrete bridges

Abstract

A practical and readily implementable seismic assessment procedure for multi-span reinforced concrete bridges is introduced in this paper. The procedure is based on an existing direct displacement-based assessment (DDBA) approach, and accounts for nonlinear dynamic soil–structure interaction (NLSSI) effects. Several simplified bridge structures lying on shallow foundations have been used as application examples. The validation has been done by comparing DDBA+NLSSI with the results of finite-element nonlinear time-history simulations by means of incremental dynamic analysis. Moreover, the influence of NLSSI on the assessment procedure has been evaluated by considering the same bridges with fixed base and with NLSSI effects. In spite of its simplicity that presently prevents its use for complex bridge structures, the proposed procedure is found to provide fast and reliable results, useful to give a first-level screening on a large set of bridges for highlighting the most critical situations, as well as to carry out fast parametric analyses to produce fragility curves in the framework of performance-based vulnerability/risk assessment.

Keywords::

• reinforced concrete bridge assessment
• incremental dynamic analysis
• displacement-based method
• soil–structure interaction

Acknowledgements

This work was partially funded by the Italian Department of Civil Protection and by the Rete dei Laboratori Universitari di Ingegneria Sismica (ReLUIS), in the framework of the DPC-RELUIS Research Programme (2010–2013), Line 2, ‘Displacement-based vulnerability assessment’. The authors also gratefully acknowledge the funding supports from the Category A Scholarship, which is directly sponsored by the European Commission, under the scope of its Erasmus Mundus programme – Master in Earthquake Engineering and Engineering Seismology (MEEES).