Considering the Effects of Local Uplift and Soil Elastic Perfectly Plastic Behavior on Soil-Structure Interaction Problem under Seismic Loading

Nadia El Abbas^1*, Abdellatif Khamlichi², Mohammed Bezzazi¹

1. ¹Department of Physics, Faculty of Sciences and Technics, Tangier, Morocco
2. ²Department STIC, ENSA Tetouan, Tetouan, Morocco

Published in The Third NZAAR International Event Series on Natural and Built Environment, Cities, Sustainability and Advanced Engineering, Kuala Lumpur, Malaysia, 15 July 2017, pages 108 to 115. New Zealand Academy of Applied Research. ISSN 2463-5979 (online), 2463-5960 (print). Indexed in the Web of Science Core Collection, Conference Proceedings Citation Index (Clarivate).

Abstract

Seismic response of an interacting soil-structure system has been studied by taking into account elastic perfectly plastic soil behavior and local uplift of the foundation. The structure was modeled by an equivalent flexible beam mounted on a rigid foundation that interacts with basement soil. This last was modeled by means of discrete Saint Venant’s units mounted in parallel and distributed over the entire width of the foundation. Each unit consists of an elastic element which is connected in series with a plastic element having constant flowing stress. The rotation was considered to remain small. The equations governing the problem were derived by taking into account the equilibrium of the coupled soil-structure system where the mat of the structure was idealized as a single-degreeof-freedom. The obtained non-linear system of ordinary differential equations was integrated by using the Matlab command ode15s. A parametric analysis was then performed in order to evaluate the maximum response of the system under seismic loading as function of the selected soil model and key dimensionless parameters that include the slenderness ratio and the ratio of mat elastic resonance frequency to the vertical resonance frequency of foundation. The obtained results have shown that taking into account local uplift of the foundation under seismic loading yields smaller rotational angles than those obtained for a purely elastic analysis. Tip horizontal displacement can however be increased or decreased by considering the soil plasticity.

Keywords: Elastic-perfectly Plastic; Local Uplift; Soil-Structure Interaction

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Copyright © New Zealand Academy of Applied Research Ltd 2017. All rights reserved. Reproduced in the GDI Academy archive from the original proceedings without change to the authors’ text.