City Research Online

Abstract

Over the last decades, the findings of numerous analytical studies, experiments and in-situ observations have highlighted the importance of the deck-abutment-backfill interaction on the seismic response of bridges. These findings have allowed various research groups to develop closed-form relationships that describe the nonlinear behaviour of the abutment-backfill system. Such relationships have been broadly used in research, reflected in modern seismic codes and guidelines, and incorporated in nonlinear analysis software. However, the behaviour of the abutment-backfill systems after the attainment of peak strength has been neither studied to a sufficient extent from the analysis point of view nor included in the constitutive models of widely used nonlinear analysis software packages, such as OpenSees, even though large-scale tests have captured this critical phase of the response. The softening region of the response of the backfill has been addressed by some hardening/softening plasticity models that are not appropriate when simpler approaches (like Winkler springs) are used. Notably, the estimation of the abutment-backfill response at any level of seismic intensity is necessary for an appropriate fragility analysis of a bridge since the abutment-backfill component is almost always considered to affect at least some aspects of the bridge response and its failure is one of the possible failure modes that should be accounted for. In the above context, the main aim of the work presented herein is to propose an extended version of the 'Hyperbolic Gap' OpenSees material, the so-called 'Hyperbolic Gap Softening' material, which allows the user to define a set of parameters that describe the softening branch of the backbone curve of an abutment-backfill system. In addition to tests of the new model using a simple configuration, results of response history analyses of a case study bridge with different abutment-backfill properties are also reported, with a view to verifying the applicability of the proposed model and investigating the importance of capturing the post-peak abutment-backfill behaviour on the estimation of the response of a bridge.

Publication Type:	Conference or Workshop Item (Paper)
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TH Building construction
Departments:	School of Science & Technology School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

Export

Downloads