Miranda E., Kazantzi, A.K., Vamvatsikos D. (2018). New approach to the design of acceleration-sensitive non-structural elements in buildings. Proceedings of the 16th European Conference on Earthquake Engineering, Thessaloniki, Greece.
Abstract | Nonstructural elements are typically at the end of a long chain of uncertainties making them particularly challenging to design or to estimate their seismic performance. Seismic design of nonstructural elements is typically based on over simplistic equations to estimate equivalent static forces that not only neglect the dynamic properties of the nonstructural element and of the building in which they are mounted on, but they also use large component force reduction factors that have no rational basis. Floor motions are characterized by being narrowband motions that produce extremely large accelerations on nonstructural elements whose frequencies of vibration coincide with those of the building in which they are mounted. For many years now, seismic design of structures relies on the identification of predetermined locations where non-linearities are expected to occur in the event of moderate or severe earthquake ground motions and other components and connections are designed to remain elastic. At present time, there is no equivalent approach in the design of nonstructural elements. The purpose of this paper is to introduce a new approach in which a new type of bracing elements of nonstructural elements are designed and detailed to work as fuses that limit forces acting not only in the nonstructural elements but also in the attachments to the structure and in the attachment(s) to the nonstructural element. It is shown that the proposed approach, which accounts for the narrow-band characteristics of floor motions, not only results in reductions in design forces but can also result in important reductions in deformation demands, especially for components that are tuned to modal frequencies of the building in which they are mounted on.