Seismic damage thresholds and design methods for two-elevation continuous ceiling systems

Liangjie Qi

doi:10.1016/j.engstruct.2021.113530

2022-01-01

PRE

Liangjie Qi

Masahiro Kurata *

Yoshiki Ikeda

DOI：10.1016/j.engstruct.2021.113530

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摘要

En 中文

The rise-up part of a two-elevation suspended ceiling system, where the ceiling height of two adjacent space or rooms differs due to the usage plan, frequently sustains damage under earthquakes. In current construction practice, the rise-up part in ceilings is temporarily reinforced for construction by the judgment of subcontractors without an engineering design. Thus, this paper addresses seismic damage thresholds and proposes a design method for suspended two-elevation continuous ceiling systems, aiming to provide a rationale for the construction of two-elevation ceilings. First, the vulnerable parts of the ceiling system are examined in a shake table test, where three primary damage patterns are observed. Fragility curves and communications with engineers of a ceiling company indicate a condition of drift between two elevations >= 1/100 as a threshold for judging a repair need. The analytical model of the rise-up part and the overall two-elevation ceiling are then built to investigate the effects of clearance around ceiling edges, the mass ratio of higher to lower elevation, the distance between TPBBs, and the specification of suspension bars on the seismic behavior of two-elevation ceiling systems. Finally, a design method for two-elevation ceiling systems, including the design flowchart and examples, is proposed.

Keyword:

Two-elevation continuous ceiling system

Rise-up part

Temporarily positioned bracing bar

Damage threshold

Design method