City Research Online

Abstract

The governing equations of motion for bridges with rocking piers of unequal height and unequal span lengths are derived accounting for the effect of end joint gaps and the abutment-backfill system. The attenuation of the rocking motion stems from the impacts at the rocking interfaces, described through the coefficient of restitution, and also from the impacts (pounding) of the superstructure on the abutment backwalls. This is the first study that combines both energy dissipation sources in the analytical derivation of the equations of motion. The results of response-history analysis of bridges with different levels of asymmetry in their pier height show that the performance of both the symmetric and asymmetric configurations is very similar with regard to longitudinal displacements. Although the studied bridges safely resisted ground motions with an intensity about twice that of the design earthquake, regardless of the degree of asymmetry, it was found that the higher the difference in the pier height, the larger is the rotation of the superstructure due to the differential uplift of the piers, a point that has to be addressed in seismic design for rocking response.

Publication Type:	Article
Additional Information:	This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://pubs.asce.org/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=2147486637&libID=2147486637
Publisher Keywords:	Rocking bridges, unequal pier height, asymmetry, abutment, backfill, analytical methods, rigid body dynamics
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TG Bridge engineering
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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