ABSTRACT

Suspended ceiling systems are among the most frequently reported earthquake-vulnerable nonstructural elements. Despite their importance, a rational seismic design procedure for suspended ceiling systems has not been developed because of their complex details and behavior. In this study, the seismic performance of direct- and indirect-hung suspended ceilings was evaluated based on shake table tests. In particular, a large-size ceiling specimen, comparable to an actual constructed size, was tested using an array of two shake tables and a highly stiff test frame with overall dimensions of 13 (length) × 5 (width) × 3 (height) m. In addition, six smaller specimens were tested using one shake table. All the specimens were prepared as free-floating systems by permitting free movements at the four edges. Based on the test results, key engineering parameters related to acceleration amplification and natural frequency were identified and the overall seismic performance was evaluated. Compared with the extensive failure observed in the lay-in panel ceiling specimens, marginal damage occurred around the pounded edge in the continuous panel ceiling specimens because of the robust restraining effects of the screw-attached panels on the ceiling grid members. The median amplification factors observed in the tested suspended ceiling specimens were about 1.80 and 1.75 for the vertical and horizontal directions, respectively. The dynamic behavior of the tested indirect-hung suspended ceilings which used long hanger bolts was significantly different from the pendulum behavior observed in the direct-hung suspended ceilings. The unidirectional rotation-restraining characteristic of the hanger bolt connection imparted different behaviors in each orthogonal direction. The natural frequencies of the tested suspended ceilings were well predicted when the deformed shape of the hanger bolt was modeled as a single curvature bending in the rotation-free direction and a double curvature bending in the rotation-restrained direction. The damage evaluation of each ceiling system was also presented through incremental-intensity shake table testing.

摘要

吊顶系统是最常报告的易受地震影响的非结构构件之一。尽管它们很重要，但由于其复杂的细节和行为，尚未开发出用于吊顶系统的合理抗震设计程序。在这项研究中，直接和间接悬挂式吊顶的抗震性能基于振动台试验进行了评估。特别是，使用一组两个振动台和一个整体尺寸为 13（长）×5（宽）×3（高）的高刚性测试框架对与实际构造尺寸相当的大尺寸天花板样品进行了测试。米。此外，使用一个振动台测试了六个较小的样品。通过允许在四个边缘自由移动，将所有样本准备为自由浮动系统。根据测试结果，确定了与加速度放大和固有频率相关的关键工程参数，并评估了整体抗震性能。与在嵌入式面板天花板试样中观察到的广泛破坏相比，由于螺钉连接面板对天花板网格构件的强大约束作用，连续面板天花板试样的冲击边缘周围发生了边际损坏。在测试的吊顶样本中观察到的中值放大因子在垂直和水平方向分别约为 1.80 和 1.75。测试的使用长吊杆螺栓的间接悬挂式吊顶的动态行为与在直接悬挂式吊顶中观察到的钟摆行为显着不同。吊杆螺栓连接的单向旋转约束特性在每个正交方向上赋予了不同的行为。当吊顶螺栓的变形形状被建模为无旋转方向的单曲率弯曲和旋转受限方向的双曲率弯曲时，可以很好地预测测试的吊顶的固有频率。还通过增量强度振动台测试对每个天花板系统的损坏评估进行了介绍。当吊顶螺栓的变形形状被建模为无旋转方向的单曲率弯曲和旋转受限方向的双曲率弯曲时，可以很好地预测测试的吊顶的固有频率。还通过增量强度振动台测试对每个天花板系统的损坏评估进行了介绍。当吊顶螺栓的变形形状被建模为无旋转方向的单曲率弯曲和旋转受限方向的双曲率弯曲时，可以很好地预测测试的吊顶的固有频率。还通过增量强度振动台测试对每个天花板系统的损坏评估进行了介绍。