The quantification of non‐structural seismic performance factors is a crucial step to improve the seismic performance of non‐structural elements (NSEs). Non‐structural seismic performance factors ...currently included in modern seismic design provisions are mainly based on engineering judgment and have not been calibrated to meet specific performance objectives. This makes the seismic performance of NSEs designed according to force‐based procedures uncertain at best. Previous studies have proposed a general framework for the quantification of non‐structural seismic performance factors. However, due to the necessity of considering the supporting structure dynamic properties in the estimation of the seismic demand, the required computational overhead can make the process unfeasible in some cases depending on the target supporting structure population and the pursued performance objectives. This paper proposes a procedure to estimate the seismic demand on NSEs for the quantification of non‐structural seismic performance factors that drastically reduces the required computational overhead. The proposed procedure makes use of synthetic floor accelerograms to describe in terms of seismic demand an entire population of supporting structures and ground motion sets. The proposed procedure is validated against a complete multiple‐stripe non‐linear time history analysis by deriving and comparing fragility curves. The results of the validation demonstrate that the proposed procedure is able to derive fragility curves that closely match the ones generated by using a multiple‐stripe analyses with remarkable savings in computational time and output storage size.
Lessons from recent earthquakes have provided a tough reality check of the traditional seismic design approach and technologies, highlighting the urgent need for a paradigm shift of performance‐based ...design criteria and objectives toward low‐damage design philosophy and technologies for the whole building system. Modern society is asking for “earthquake proof” resilient buildings that are able to withstand seismic events without compromising their functionality. The EU‐funded SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe Project) project discussed in this paper provided the opportunity to develop and validate within the European context an integrated seismic low‐damage prototype, including main structure and non‐structural elements, for the next generation of high‐performance buildings. This paper presents an overview of the research, involving three‐dimensional shake table tests of a two‐storey 1:2 scaled timber‐concrete post‐tensioned dissipative low‐damage structure “dressed” by earthquake‐resistant gypsum/masonry partitions and glass/concrete facades. Specimen details, construction and assembly phases, test setup, and experimental results are discussed. After many cycles of input motions at increasing levels of seismic intensity (higher than Collapse Prevention Limit State), the integrated building system exhibited a very high seismic performance. The experimental campaign carried out at the National Laboratory of Civil Engineering in Lisbon confirmed the unique potential of low‐damage technologies and the opportunity for their widespread implementation into design practice.
•The interaction of the roof's horizontal diaphragm with the structural and non-structural elements influences the seismic behaviour of industrial buildings.•It was obtained a correlation between the ...stiffness required for a rigid behaviour at the roof level in terms of the shape of the building.•The consideration of a rigid diaphragm tends to produce a more realistic seismic behaviour of the overall structure.•The contribution of facade cladding wall panels significantly influences the seismic behaviour of the building, especially for high-rise buildings.
The seismic behaviour of precast reinforced concrete industrial structures has been extensively investigated in recent decades, especially after the damage caused by recent earthquakes. The interaction of the roof's horizontal diaphragm with the structural and non-structural elements can influence the seismic behaviour of these buildings. Thus, the present study aims to investigate this interaction, through nonlinear static and dynamic analyses using a simplified macro element to simulate the behaviour of cladding panels and an equivalent truss approach to simulate the roof in-plane stiffness. The analyses were performed on several structural models considering the current European single-storey precast reinforce concrete industrial building stock, with or without cladding wall panels, and with rigid or flexible diaphragm roof. Despite the uncertainties associated with the ability of common roof systems to ensure a rigid diaphragm, the analyses allowed the establishment of a correlation between the buildings generic properties and the roof horizontal stiffness required to approach a rigid diaphragm effect. In general, the results show that the consideration of a rigid diaphragm in numerical models may tend to produce a more realistic seismic behaviour of the overall structure. Furthermore, the contribution of facade cladding wall panels significantly influences the seismic behaviour of the building, especially for high-rise buildings.
Non-structural elements represent most of the total construction cost of typical buildings. A significant portion of the total losses in recent earthquakes worldwide, has been attributed to damage to ...non-structural elements. Damage to non-structural elements occurs at low levels of ground shaking, and can significantly affect the post-earthquake functionality of buildings. However, in Europe, limited prescriptions are provided in the codes for seismic design of non-structural elements and this may partially explain why it is so common for these elements to perform poorly during earthquakes. This paper describes the observed damage to non-structural elements following the 2016 Central Italy earthquake. The most commonly damaged elements were partition walls, ceiling systems, non-structural vaults, chimneys, and storage racks. As a result, it was highlighted the need to introduce seismic regulations devoted to improving the seismic performance of non-structural elements and to reduce the associated economic losses, loss of functionality, and potential threats to life safety.
Abstract
This paper presents a general seismic classification procedure for acceleration‐sensitive non‐structural elements (NSEs) based on seismic qualification shake table testing and provides an ...application example for electrical cabinets in Italy. The proposed seismic classification procedure requires the definition of a set of required response spectra (RRS) for qualification shake table testing defined at different seismic hazard levels and the definition of a formal procedure to generate a test input motion. Each required response spectrum at a given seismic hazard level is then linked to different class levels and the requirements that an NSE should present to achieve each class level are defined. Using this framework, a seismic classification procedure for NSEs is developed for Italy, in which, the RRS are defined according to a peak floor spectral acceleration seismic hazard map of the territory so as to predefine regions in which an NSE belonging to a given class can be installed or not according to either a life safety performance objective or a continuous operation performance objective. Also, the limitations of the proposed seismic classification procedure are outlined. Finally, a nominal application example is presented in which four electrical cabinet specimens were tested on a shake table and their class levels were defined. The results of the application example are used to nominally show how the proposed classification procedure could be applied to discriminate between different types of the same NSE depending on the specific desired application.
This study assesses the number of injuries directly caused by structural and non-structural damage within New Zealand commercial buildings from notable shaking events between 2010 and 2014 and the ...treatment level required. After applying filtering to a comprehensive New Zealand earthquake-induced injury database, 947 injuries matched this study's scope, of which 174 were fatal. Collapse or movement of non-structural elements caused 556 injuries; though over 85% were treated outside hospitals and none were fatal. In contrast, 60% of the 220 structural damage-related injuries were fatal. The high injury occurrence from non-structural damage highlights its high risk of injury burden. The two leading causes of non-structural damage-related injuries were movement and/or damage of contents (e.g. furniture) and ceiling and services damage. This emphasizes the importance of reducing injury from movement and damage of non-structural elements during earthquake shaking, in addition to reducing fatalities by preventing structural and masonry collapse.
Some experimental studies on the structural response of constructions made of cold-formed steel (CFS) profile are ongoing at University of Naples “Federico II”. Since the connections between panels ...and CFS frame have a fundamental role in the global response of CFS constructions, a specific task was devoted to test this kind of elements. In particular, the main object of the activity is the experimental characterization of solutions for panel-to-CFS connections commonly used in common practice, with reference to gypsum and cement-based solutions. In order to define their mechanical properties, 54 tests were carried out in order to assess the effect of panel type, thickness profile, screw diameter and number of panel layers. The results of this experimental investigation are discussed in this paper. Furthermore, the experimental values of shear strength obtained in the tests are compared with the available theoretical predictions and experimental data from literature.
•Connections influence the response of the whole structure in CFS systems.•The experimental characterization of panel-to-CFS connections is discussed.•9 different connection configurations were tested for a total of 54 tests.
The seismic performance of non-structural elements is now recognized to be a key issue in the seismic assessment and earthquake related loss estimation of buildings, both at the individual and ...regional scale. The evaluation of the seismic demand on non-structural elements in many modern building codes is often based on inaccurate distributions of floor accelerations. For this reason, some design oriented simplified methodologies have been developed recently to predict floor response spectra in reinforced concrete buildings. Although the influence of masonry infills on the seismic performance of reinforced concrete buildings has been widely demonstrated, infills are generally neglected both in the design and in the evaluation of floor response spectra, which could lead to un-conservative design of non-structural elements. In this paper, the effect of masonry infills on absolute acceleration and relative displacement floor response spectra for reinforced concrete buildings subjected to frequent (serviceability level) earthquakes is investigated through a probabilistic framework. A database of one hundred masonry infilled reinforced concrete frames, representative of the European context, was generated and each building analyzed through nonlinear time history analyses. From the results of these analyses, the acceleration and displacement response spectra at different floor levels of both bare and infilled frame archetypes were then computed. The effectiveness of the most common assumptions made in regional risk models to estimate the non-structural losses is investigated and a first attempt at a more refined approach taking into account the effect of masonry infills is proposed.
The results of a preliminary experimental study carried out to evaluate the seismic behaviour of a bracing system, designed to reduce the seismic vulnerabilities in lightweight steel (LWS) suspended ...ceilings, are presented in the current paper. The experimental investigation involved 12 cyclic tests on the bracing system carried out according to FEMA 461 loading protocol. A special test set-up for a universal testing machine was designed to test the system under two different directions of the horizontal seismic action, which could cause one or two braces of the bracing system to act as an element under tension. Test results were analysed in terms of strength, stiffness and damage phenomena. The study also demonstrates that a preliminary evaluation of the experimental cyclic response of a bracing system for LWS suspended ceilings under horizontal seismic actions can be performed by using a universal testing machine. Two case studies were developed in order to give preliminary information about the evaluation of the maximum ceiling area that a single bracing system can cover. The two case studies are residential reinforced concrete six-storey buildings located in two different geographical locations in Italy: Naples and L'Aquila, which are characterized by medium-high (0.17 g) and high (0.26 g) intensity of seismic loads, respectively. Based on the assumption of a weight for the ceilings in the range from 50 to 150 N/m2, a ceiling area ranging from 5.5 to 32 m2 was defined as the maximum area that a bracing system can cover.
•Cyclic testing of an innovative connecting device used in a bracing system of LWS suspended ceilings.•Efficient use of universal testing machine for testing the ceiling bracing system through specially designed test set up.•Response of bracing system is investigated in two directions.•Evaluation of ceiling areas that can be covered with the newly proposed system.
