Fundamental Dynamics and Performance Assessment of Three-Dimensional Seismic Isolation
type: CreativeWork
description: Seismic isolation is an effective technique used to mitigate effects of ground shaking and achieve higher seismic performance in building structures. Recent research has suggested that vertical excitation has significant effects on the structural response during an earthquake. In this dissertation, the dynamic response and control of buildings with 3-dimensional (3D) isolation systems is explored. First, the fundamental dynamic response of a simplified model consisting of a rigid block resting on isolation bearings is studied. The overall structural response of the 3D isolated block is evaluated through drift ratio, vertical and horizontal displacement and acceleration amplification factors. A parametric study is carried out to evaluate the effect of different site conditions, building aspect ratio and 3D isolation parameters on the structure and bearing response. The results show that effective 3D isolation is achieved by designing the system with vertical isolation period in the range of 0.5 - 1.0 sec. Also, the horizontal (TH) and vertical (TV) isolation periods should not be closely coupled, and TH should be selected to be much longer than TV. Structural responses are seen to increase for increasing site class (increasingly softer soil) over the entire parameter range. Increasing horizontal ζH and vertical damping ratios ζV, leads to decreasing drift ratios and vertical bearing displacement. However, increasing h/b leads to an increase in rocking, which consequently impacts the relative drift ratio between the top and the base and the vertical bearing displacement.Next, a concept is proposed for 3D isolation that combines elastomeric bearings to resist horizontal ground shaking in series with bilinear liquid spring (BLS) - controllable magnetorheological fluid dampers (CMRD) to resist vertical shaking. The simplified rigid block model is extended to predict the response of the building isolated with BLS-CMRD devices under earthquake loading. BLS-CMRDs are simula…
abstract: Seismic isolation is an effective technique used to mitigate effects of ground shaking and achieve higher seismic performance in building structures. Recent research has suggested that vertical excitation has significant effects on the structural response during an earthquake. In this dissertation, the dynamic response and control of buildings with 3-dimensional (3D) isolation systems is explored. First, the fundamental dynamic response of a simplified model consisting of a rigid block resting on isolation bearings is studied. The overall structural response of the 3D isolated block is evaluated through drift ratio, vertical and horizontal displacement and acceleration amplification factors. A parametric study is carried out to evaluate the effect of different site conditions, building aspect ratio and 3D isolation parameters on the structure and bearing response. The results show that effective 3D isolation is achieved by designing the system with vertical isolation period in the range of 0.5 - 1.0 sec. Also, the horizontal (TH) and vertical (TV) isolation periods should not be closely coupled, and TH should be selected to be much longer than TV. Structural responses are seen to increase for increasing site class (increasingly softer soil) over the entire parameter range. Increasing horizontal ζH and vertical damping ratios ζV, leads to decreasing drift ratios and vertical bearing displacement. However, increasing h/b leads to an increase in rocking, which consequently impacts the relative drift ratio between the top and the base and the vertical bearing displacement.Next, a concept is proposed for 3D isolation that combines elastomeric bearings to resist horizontal ground shaking in series with bilinear liquid spring (BLS) - controllable magnetorheological fluid dampers (CMRD) to resist vertical shaking. The simplified rigid block model is extended to predict the response of the building isolated with BLS-CMRD devices under earthquake loading. BLS-CMRDs are simula…
author: Eltahawy, Walaa M. G.
keywords: 3D Building, Control Strategy, Rigid Block, Seismic isolation, Structural Response, Vertical acceleration
date published: 2018
date modified: 2026-07-27T21:46:52Z
provider: University of Nevada - Reno
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Nevada - Reno

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11714/4861