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原文传递 ANALYTICAL MODELING OF SPREAD FOOTING FOUNDATIONS FOR SEISMIC ANALYSIS OF BRIDGES.

题名：	ANALYTICAL MODELING OF SPREAD FOOTING FOUNDATIONS FOR SEISMIC ANALYSIS OF BRIDGES.
作者：	McGuire-JW; Cofer-WF; Marsh-ML; McLean-DI
关键词：	ANALYTICAL-MODELS; SPREAD-FOOTINGS; BRIDGE-FOUNDATIONS; SEISMIC-RESPONSE; SOIL-STRUCTURE-INTERACTION; ENERGY-DISSIPATION; SOIL-STIFFNESS; EARTHQUAKES-; RADIATION-DAMPING
摘要：	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.
总页数：	Transportation Research Record. 1994. (1447) pp80-92 (9 Fig., 1 Tab., 26 Ref.)
报告类型：	科技报告