Dynamic Analysis of Flexible Stepping Frames for Earthquakes

Fuente: arXiv
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Main Authors: Alimoradi, Arzhang, Beck, James L.
Format: Preprint
Published: 2025
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author Alimoradi, Arzhang
Beck, James L.
author_facet Alimoradi, Arzhang
Beck, James L.
contents This paper investigates the nonlinear dynamics of stepping flexible frames under seismic excitation. The conventional iterative method of solution of peak quasi-dynamic displacement of stepping frames is not guaranteed to converge. To address this limitation, we present closed-form solutions and stability criteria for displacement response of stepping flexible frames. Bifurcation of displacements in response of such systems is next studied through the extension of dynamics of stepping rigid bodies. An approximate analytical expression is presented to account for the effects of moving resonance under earthquake ground motions. The closed-form solutions for displacement demand can be readily adjusted to incorporate the influence of moving resonance on the quasi-dynamic response of stepping oscillators. While the quasi-dynamic method of analysis may be useful in the early stages of design, numerical integration of the nonlinear system of differential equations of motion is recommended for the solution of dynamic response in such applications. Implications for formal limit-state analysis of stepping response are discussed, accompanied by several examples demonstrating the procedures.
format Preprint
id arxiv_https___arxiv_org_abs_2505_06239
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamic Analysis of Flexible Stepping Frames for Earthquakes
Alimoradi, Arzhang
Beck, James L.
Geophysics
Dynamical Systems
Primary: 74H45, Secondary: 70K30, 70K50, 37N99, 74H99
This paper investigates the nonlinear dynamics of stepping flexible frames under seismic excitation. The conventional iterative method of solution of peak quasi-dynamic displacement of stepping frames is not guaranteed to converge. To address this limitation, we present closed-form solutions and stability criteria for displacement response of stepping flexible frames. Bifurcation of displacements in response of such systems is next studied through the extension of dynamics of stepping rigid bodies. An approximate analytical expression is presented to account for the effects of moving resonance under earthquake ground motions. The closed-form solutions for displacement demand can be readily adjusted to incorporate the influence of moving resonance on the quasi-dynamic response of stepping oscillators. While the quasi-dynamic method of analysis may be useful in the early stages of design, numerical integration of the nonlinear system of differential equations of motion is recommended for the solution of dynamic response in such applications. Implications for formal limit-state analysis of stepping response are discussed, accompanied by several examples demonstrating the procedures.
title Dynamic Analysis of Flexible Stepping Frames for Earthquakes
topic Geophysics
Dynamical Systems
Primary: 74H45, Secondary: 70K30, 70K50, 37N99, 74H99
url https://arxiv.org/abs/2505.06239