A simplified Nonlinear Sway-Rocking model for evaluation of seismic response of structures on shallow foundations. Issue 81 (February 2016)

• Record Type: Journal Article
• Authors: Lu, Yang; Marshall, Alec M.; Hajirasouliha, Iman
• Is Part Of: Soil dynamics and earthquake engineering. Issue 81(2016:Feb.)
• Page Start: 14
• Page End: 26
• Publication Date: 2016-02
• Subjects: Soil-structure interaction -- Simplified model -- Nonlinear analysis -- Soil non-homogeneity -- Coupled sway-rocking response; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2015.11.002
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: This paper presents a simplified Nonlinear Sway-Rocking model as a preliminary design tool for seismic soil-structure interaction analysis. The proposed model is intended to capture the nonlinear load-displacement response of shallow foundations during strong earthquake events where foundation bearing capacity is fully mobilised. Emphasis is given to heavily-loaded structures resting on a saturated clay half-space. The variation of soil stiffness and strength with depth, referred to as soil non-homogeneity, is considered in the model. Although independent springs are utilised for each of the swaying and rocking motions, coupling between these motions is taken into account by expressing the load-displacement relations as functions of the factor of safety against vertical bearing capacity failure ( FSv ) and the moment-to-shear ratio ( M / H ). The simplified model has been calibrated and validated against results from a series of static push-over and dynamic analyses performed using a more rigorous finite-difference numerical model. Despite some limitations of the current implementation, the concept of this model gives engineers more degrees of freedom in defining their own model components, providing a good balance between simplicity, flexibility and accuracy. Highlights: A simplified model is developed to capture nonlinear seismic foundation response. The effects of soil nonlinearity and heterogeneity are accounted for in the model. A unique dimensionless backbone is employed for each of sway and rocking motions. The FLAC 3D numerical code is used to calibrate and validate the simplified model.