Progressive Collapse of the Base-Isolated Frame Structures Supported by Stepped Foundation in Mountainous City

Youfa Yang,Tianhang Yang,Anxu Chen

doi:10.3390/app12042151

Abstract

Base-isolated frames supported by stepped foundation in mountainous areas possess their own particularity, so its progressive collapse dynamic response performance and dynamic effect propagation path are very different from those of ordinary flat ground-isolated structural systems. In order to study the progressive collapse performance of the base-isolated frames supported by stepped foundation in mountainous areas under two-directional coupled dynamic excitation, a four-span three-story plane frame demolition column test was simulated to verify the reliability of the computing platform. The common ground motion and three types of long-period ground motions were selected, and the two-dimensional dynamic coupling of the ordinary flat ground isolation structure and the base-isolated frames supported by stepped foundation in mountainous areas was obtained based on the demolition method. First, the seismic isolation structure was subjected to the collapse dynamic response under the vertical unbalanced load, then the collapse dynamic response under the vertical unbalanced load and the horizontal seismic coupling excitation was made; the two were compared and analyzed. It can be used as a reference for the design of progressive collapse of the frame structure of the base-isolated frames supported by stepped foundation in mountainous areas.

Highlights

Frames supported by stepped foundation is a common structural form in the construction of mountainous cities
In order to study the difference in the progressive collapse resistance of the base isolation flat structure and the base-isolated frames supported by stepped foundation in mountainous areas, this paper designed a
In order to study the difference in the progressive collapse resistance of the base isolation flat structure and the base-isolated frames supported by stepped foundation in mountainous areas, this paper designed a common frame structure and a frame supported by stepped foundation

Summary

Introduction

Frames supported by stepped foundation is a common structural form in the construction of mountainous cities. It refers to a structural system in which there are two fixed ends in the same unit that are not in the same plane, and the floor is set according to the height below the highest ground point. The dynamic response characteristics and the transmission path of dynamic effects of progressive collapse were quite different from that of ordinary flat-ground isolation structure systems. Since the events of “Ronan point apartment collapse in UK” and “9.11”, scholars at home and abroad have carried out a lot of research on the progressive collapse of structures. Progressive collapse [1] refers to local destruction of the structure, which leads to a chain reaction leading to the destruction of adjacent members, resulting in extensive destruction or overall collapse that is disproportionate to the initial failure

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