Design Of Non-structural Elements Research Articles

Reinforced Concrete Infilled Frames

Masonry-Infilled Reinforced Concrete Frames are a very widespread structural typology all over the world for civil, strategic or productive uses. The damages due to these masonry panels can be life threatening to humans and can severely impact economic losses, as shown during past earthquakes. In fact, during a seismic event, most victims are caused by the collapse of buildings or due to nonstructural elements. The damage caused by an earthquake on nonstructural elements, i.e., those not belonging to the actual structural body of the building, is important for the purposes of a more general description of the effects and, of course, for economic estimates. In fact, after an earthquake, albeit of a low entity, it is very frequent to find even widespread damages of nonstructural elements causing major inconveniences even if the primary structure has reported minor damages. In recent years, many territories have been hit worldwide by strong seismic sequences, which caused widespread damages to the nonstructural elements and in particular to the masonry internal partitions and the masonry infill panels of the buildings in reinforced concrete, with damage to the floor and out-of-plane expulsions/collapses of single layers. Unfortunately, these critical issues have arisen not only in historic, but also in recent buildings with reinforced concrete, in many cases exhibiting inadequate seismic behavior, only partly attributable to the intrinsic vulnerability of the masonry panels against seismic actions. Such problems are due to the following aspects: lack of attention to construction details in the realization of the construction, use of poor-quality materials, and above all lack of design tools for the infill masonry walls. In 2018, regarding the design of nonstructural elements, the formulation of floor spectra has been recently introduced in Italy. This entry article wants to focus on all these aspects, describing the state of the art, the literature studies and the design problems to be solved.

Performance objectives for non-structural elements

The recent earthquakes in New Zealand have raised awareness of the seismic vulnerability of non-structural elements and the costly consequences when non-structural elements perform poorly. Impacts on business continuity due to the damage of non-structural elements has been identified as a major cost and disruption issue in recent earthquakes in New Zealand, as well as worldwide. Clearly improvements in performance of non-structural elements under earthquake loads will yield benefits to society.
 This paper explores the intended and expected performance objectives for non-structural elements. Possible historic differences in performance objective expectations for non-structural elements between building services engineers, fire engineers and structural engineers are discussed. Wider construction industry expectations are explored along with our experience of client and regulatory authority views.
 The paper discusses the application and interpretation of the New Zealand earthquake loadings Standard NZS1170.5:2004 for the design of non-structural elements including possible differences in interpretation between building services, structural and fire engineers leading to confusion around the expected performance of non-structural elements under different limit states. It is based on the experience of several of the authors as members of the Standards committee for NZS1170.5:2004.
 The paper concludes by discussing changes to NZS1170.5:2004 the authors have proposed as members of the NZS1170.5 Standards committee to clarify and address the identified issues. These changes clarify the classification of parts, requirements for consideration earthquake imposed deformations, parts supported on ledges, potential falling of parts, the combination of fire and earthquake loads, and the requirement for parts to be designed for both serviceability and ultimate limit states along with the effective introduction of a serviceability limit state for parts for occupational continuity.