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Flexibility of superstructures and supports in the seismic analysis of simple bridges
Author(s) -
Alfawakhiri Farid,
Bruneau Michel
Publication year - 2000
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/(sici)1096-9845(200005)29:5<711::aid-eqe936>3.0.co;2-#
Subject(s) - simple (philosophy) , flexibility (engineering) , structural engineering , seismic analysis , engineering , geology , civil engineering , computer science , forensic engineering , construction engineering , mathematics , statistics , philosophy , epistemology
This paper addresses the elastic dynamic response of simply supported bridges to ground motion in their transverse direction. The interaction between superstructure and support flexibilities is studied in a systematic manner for symmetric spans. The bridges are modelled as beams with uniformly distributed mass and elasticity, simply supported at the ends by elastic springs. It is shown that a dimensionless stiffness index, which reflects the relative stiffness of the superstructure compared to the stiffness of the substructure, completely defines the dynamic mode shapes of the model. Useful closed‐form expressions, based on approximate shape functions, are derived for the dynamic parameters of the first mode, and their accuracy is assessed. The effect of the stiffness index on these dynamic parameters is investigated. Numerical case studies are presented to illustrate the use of proposed equations in the seismic analysis of bridges. Copyright © 2000 John Wiley & Sons, Ltd.