00672560

Component

http://onlinepubs.trb.org...trr/1994/1447/1447-010.pdf

https://scholar.google.co...Lean&publication_year=1994

The way bridges respond to seismic excitation may be significantly influenced by the dynamic properties of their foundations. Within current design practice, foundation elements typically are considered as elastic springs, without consideration to material and radiation damping. General foundation models are identified that are suitable for (a) modeling soil-structure interaction for the seismic analysis of bridges, (b) modifying an existing, nonlinear, seismic-bridge-analysis computer program to include a new element capable of representing such models, and (c) conducting a parametric study to assess the effect of the increased energy dissipation mechanisms on the seismic response of bridge substructures. Three different models for spread-footing foundations are identified, applied to a typical two-column bridge bent, and compared with conventional elastic and fixed-base models. Three soil-stiffness values are considered, and two earthquake records, each with two different intensities, were applied to the bent. Maximum values of displacement, plastic-hinge rotation, and cumulative plastic hinge rotations were noted and compared. It was concluded that the use of the spread-footing foundation models can produce an important change in the bridge response to seismic activity when compared with that of the fixed-base model--depending on the frequency content of the earthquake and the stiffness of the soil. The effects of radiation damping were observed to be insignificant for foundations on stiff soil but important for those on soft soil. In addition, the performance of the simpler, damped foundation models was found to be quite similar to that of the more complex models. The models' accuracy was not verified, but the structural response of incorporating them was explored.

This paper appears in Transportation Research Record No. 1447, Design and Construction of Auger Cast Piles, and Other Foundation Issues. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01401277

English

p. 80-92

1994

Transportation Research Record

0309060532

Figures (9) ; References (26) ; Tables (1)

Bridge foundations; Dissipation; Earthquakes; Mathematical models; Seismicity; Soil structure interaction; Soils; Spread footings; Stiffness

Analytical models; Seismic response; Soil stiffness

Bridges and other structures; Design; Energy; Geotechnology; Highways; I24: Design of Bridges and Retaining Walls

TRIS, TRB

Jan 13 1995 12:00AM

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• BITUMEN COATING FOR DOWNDRAG MITIGATION IN COHESIONLESS SOILS
• BUCKLING OF FRICTION PILES SUPPORTING BRIDGE FOUNDATIONS
• DESIGN AND CONSTRUCTION OF AUGER-CAST PILES IN FLORIDA
• DESIGN AND CONSTRUCTION OF STARSOL PILES
• DETERMINING LENGTHS OF INSTALLED TIMBER PILES BY DISPERSIVE WAVE PROPAGATION
• FORMALIZED PROCEDURE FOR QUALITY ASSESSMENT OF CAST-IN-PLACE SHAFTS USING SONIC PULSE ECHO METHODS
• LRFD CODE FOR ONTARIO BRIDGE SUBSTRUCTURES
• MANAGING THE INSTALLATION OF AUGERED CAST-IN-PLACE PILES
• NEW TECHNIQUES FOR RELIABLE PILE INSTALLATION AND PILE BEHAVIOR DESIGN AND ANALYSIS
• REDUCED IMPACT ON ADJACENT STRUCTURES USING AUGERED CAST-IN-PLACE PILES
• REVIEW OF AUGERED PILE PRACTICE OUTSIDE THE UNITED STATES
• USE OF DEEP BLAST DENSIFICATION FOR BRIDGE FOUNDATION IMPROVEMENT ON SR-504