Lightweight Steel Constructions for Seismic Areas

Lightweight steel constructions are one of the innovative constructional systems steadily increasing in spread due to their huge benefits in respect to more traditional constructional systems. Typical lightweight steel products, usually combined with gypsum, wood and cement based panels, can be used to build both structural and nonstructural systems. After a brief description of the most common lightweight steel constructional systems, this paper describes the state of the art by focusing the attention on their behaviour under seismic actions. In particular, the main past and ongoing research themes are briefly summarised and a critical comparison among seismic codes available in North America, Europe and Oceania is presented. Finally, an overview of studies carried out on this topic at the University of Naples Federico II is presented and latest research activities involving the seismic performance assessment of both lightweight steel structural and nonstructural architectonic systems though shake-table tests is provided.

Piping Fragility Evaluation: Interaction With High-Rise Building Performance

Many recent studies have emphasized the need for improving seismic performance of nonstructural systems in critical facilities in order to reduce the damage as well as to maintain continued operation of the facility after an earthquake. This paper is focused on evaluating system-level seismic fragility of the piping in a representative high-rise building. Piping fragilities are evaluated by incorporating the nonlinear finite-element model of a threaded Tee-joint that is validated using experimental results. The emphasis in this study is on evaluating the effects of building performance on the piping fragility. The differences in piping fragility due to the nonlinearities in building are evaluated by comparing the fragility curves for linear frame and nonlinear fiber models. It is observed that as nonlinearity in the building increases with increasing value of peak ground acceleration, the floor accelerations exhibit a reduction due to degradation/softening. Consequently, the probabilities of failure increase at a slower rate relative to that in a linear frame. It is also observed that a piping located at higher floor does not necessarily exhibits high fragilities, i.e., the fundamental building mode is not always the governing mode. Higher order building modes with frequencies closest to critical piping modes of interest contribute more significantly to the piping fragility. Within a particular building mode of interest, a good indicator of the amplification at different floor levels can be obtained by the product of mode shape ordinate and modal participation factor. Piping fragilities are likely to be higher at floor levels at which this product has a higher value.

Full-Scale Structural and Nonstructural Building System Performance during Earthquakes: Part II – NCS Damage States

Nonstructural components and systems (NCSs) provide little to no load bearing capacity to a building; however, they are essential to support its operability. As a result, 75–85% of the initial building financial investment is associated with these elements. The vulnerability of NCSs even during low intensity earthquakes is repeatedly exposed, resulting in large economic losses, disruption of building functionality, and concerns for life safety. This paper describes and classifies damage to NCSs observed during landmark shake table tests of a full-scale five-story reinforced concrete building furnished with a broad variety of NCSs. This system-level test program provides a unique dataset due to the completeness and complexity of the investigated NCSs. Results highlight that the interactions between disparate nonstructural systems, in particular displacement compatibility, as well as the interactions between the NCSs and the building structure often govern their seismic performance.

Damping Scaling Factors for Elastic Response Spectra for Shallow Crustal Earthquakes in Active Tectonic Regions: “Average” Horizontal Component

Ground motion prediction equations (GMPEs) for elastic response spectra are typically developed at a 5% viscous damping ratio. In reality, however, structural and nonstructural systems can have other damping ratios. This paper develops a new model for a damping scaling factor ( DSF) that can be used to adjust the 5% damped spectral ordinates predicted by a GMPE for damping ratios between 0.5% to 30%. The model is developed based on empirical data from worldwide shallow crustal earthquakes in active tectonic regions. Dependencies of the DSF on potential predictor variables, such as the damping ratio, spectral period, ground motion duration, moment magnitude, source-to-site distance, and site conditions, are examined. The strong influence of duration is captured by the inclusion of both magnitude and distance in the DSF model. Site conditions show weak influence on the DSF. The proposed damping scaling model provides functional forms for the median and logarithmic standard deviation of DSF, and is developed for both RotD50 and GMRotI50 horizontal components. A follow-up paper develops a DSF model for vertical ground motion.

Testing Protocol for Experimental Seismic Qualification of Distributed Nonstructural Systems

Building codes and standards now require seismic qualification of mechanical and electrical equipment and their mounting systems in important buildings to ensure that they remain functional during and after major seismic events. To better understand the seismic behavior of nonstructural building contents and equipment, experimental procedures have been proposed for either displacement or acceleration sensitive nonstructural components, through racking or shake table protocols, respectively. However, certain types of nonstructural systems are sensitive to both accelerations and interstory drifts. An innovative testing protocol is proposed that can subject nonstructural systems to the combined accelerations and interstory drifts expected within multistory buildings during seismic shaking. Moreover, the proposed protocol, when used with equipment such as the University at Buffalo Nonstructural Component Simulator (UB-NCS), allows for the assessment of the seismic performance of distributed nonstructural systems with multiple attachment points, and the evaluation of seismic interactions between components. The versatility and capabilities of the testing protocol are demonstrated through testing of a full-scale hospital emergency room containing typical nonstructural components and life support medical equipment.

THE LOCALITY OF THE “GLOBAL VILLAGE” IN THE ASPECT OF COMMUNICATION: PRO ET CONTRA M. MCLUHAN

The article deals with the concept of a “global village” in the aspect of communication. In the first part of the article this concept is introduced without undertaking any judgments and following a position of a judicial researcher. In the second part the conditions of the possibility of a “global village”, regarding the crucial differences of globality and villagicity and their incompatibility, are questioned. A thought is raised whether M. McLuhan's “global village”, which is constituted by contemporary information and communication technologies and treated as new media, should be assessed as a “global city”, attaching to globality some essentially new and unaccustomed meanings, inspired by the traditional socio‐cultural structural transformations to the networkful nonstructural systems. „Globaliojo kaimo“ lokalumas komunikaciniu aspektu: pro et contra M. Mcluhanui Santrauka Straipsnyje komunikaciniu aspektu tiriama M. McLuhano „globaliojo kaimo“ samprata. Pirmoje jo dalyje ši samprata pristatoma nesiimant jokių jos vertinimų ir laikantis bešališkos tyrėjo pozicijos. Antroje straipsnio dalyje kvestionuojamos „globaliojo kaimo“ galimybės sąlygos dėl esminių globalumo ir kaimiškumo skirtumų bei jų tarpusavio nesuderinamumo. Išsakoma mintis, kad McLuhano įžvelgiamas „globalusis kaimas“, kurį jo mąstymo perspektyvoje steigia dabartinės informacijos ir komunikacijos technologijos, traktuojamos kaip naujosios medijos, turėtų būti traktuojamas kaip „globalusis didmiestis“, globalumui suteikiant iš esmės naujų ir neįprastų konotacijų, inspiruotų tradicinių sociokultūrinių struktūrų transformacijų į tam tikras tinkliškas bestruktūres sistemas.