A parametric study of the influence of short-term soil deformability on the static response of building structures

Abstract

A parametric study conducted on the influence of flexible bases on the response of building structures subjected to both gravity and lateral static loads is presented. The most important parameters that are varied include the type of structural system, the type of the soil, and the embedment depth of the foundation. Both framed and dual structural systems are studied with height varying from six to twenty one stories. Base springs are established in accordance with relations available in pertinent literature and presented in a companion paper. Analyses of three-dimensional models using ETABS V 8.00 are carried out. The results presented show that all three factors have strong influence on the responses. The differences in internal forces of essential lateral-force resisting structural elements like columns and shear walls between the fixed-base and the flexible-base models are found to be significant. The fixed-base model underestimates both axial forces and moments in some columns of the dual system. The fixed-base model tends to underestimate the shear wall bending moments and axial forces, whereas it consistently overestimates the shear forces. Significant differences in the reaction moments at the foundation level are also noted between the fixed-base and flexible-base models.