SEISMIC ANALYSIS OF REINFORCED CONCRETE WALLS WITH GRANULAR INFILL

摘要

Reinforced concrete walls sandwiching granular infill may be used to enhance missile protection of selected facilities. Two behaviors complicate the seismic response of the assemblage of granular material contained by the two concrete wall elements. First, the granular material tends to settle when the walls pull apart in a breathing mode. This settling increases the lateral pressure acting on each wall, generating a set of forces that acts to spread the walls apart. Settling of the granular material combined with spreading of the walls results in breathing mode deformations that can occur in a ratcheting behavior, with the walls moving progressively further apart with each cycle of strong ground motion. Second, friction forces develop between the two walls and granular material. These forces may cause partial flexural coupling of the two walls (i.e., partial composite action).rnSoil mechanics solutions for lateral soil pressure acting in trenches are adapted to predict the lateral pressure of granular infill. The granular material is represented by a bilinear lateral response representing the active flow regime. The seismic response of granular infill concrete walls is studied using nonlinear finite element analysis.rnSimple structural models appropriate for routine seismic analysis that capture important aspects of the seismic response are proposed.