Effect of Spring-Mass-Damper Pedestrian Models on the Performance of Low-Frequency or Lightweight Glazed Floors

Funding Information: This research activity has been carried out at Department of Civil Engineering and Architecture of University of Trieste, and financially supported in the framework of “ComBioDyn” Microgrants 2022 project. Publisher Copyright: © 2023 by the authors.For structural design purposes, human-induced loads on pedestrian systems can be described by several simplified (i.e., deterministic equivalent-force models) or more complex computational approaches. Among others, the Spring-Mass-Damper (SMD), Single Degree of Freedom (SDOF) model has been elaborated by several researchers to describe single pedestrians (or groups) in the form of equivalent body mass m, spring stiffness k and damping coefficient c. For all these literature SMD formulations, it is proved that the biodynamic features of walking pedestrians can be realistically reproduced, with high computational efficiency for vibration serviceability assessment of those pedestrian systems mostly sensitive to human-induced loads (i.e., with vibration frequency f1 1/130th) or low- (1/4th) mass ratio, compared to the occupant. Normal walking scenarios with frequency in the range fp = 1.5–2 Hz are taken into account for a total of 100 dynamic simulations. The quantitative comparison of typical structural performance indicators for vibration serviceability assessment (i.e., acceleration peak, RMS, CREST) shows significant sensitivity to input SMD assumptions. Most importantly, the sensitivity of structural behaviours is observed for low-frequency systems, as expected, but also for low-mass structures, which (as in the case of glazed floor solutions) can be characterized by the use of lightweight modular units with relatively high vibration frequency. As such, major attention can be required for their vibrational analysis and assessment.publishersversionpublishe

Preliminary Experimental and Finite-Element Numerical Assessment of the Structural Performance of SMA-Reinforced GFRP Systems

In this study, the feasibility and potentiality of a novel design concept is explored by means of small scale experimental tests and Finite-Element numerical simulation. Taking advantage of the intrinsic potentiality of Shape-Memory Alloys wires able to work as adaptive actuators when subjected to joule heating, a \u2018smart-GFRP\u2019 concept consisting in Glass-Fiber-Reinforced-Polymer (GFRP) structural members with a SMA reinforcement is preliminary assessed. As shown, as far as the working temperature increases, important structural benefits can be achieved in terms of overall performance of the proposed composite systems. The potentiality of the same design concept is then further assessed by means of a practical calculation example

Cavity-aided quantum parameter estimation in a bosonic double-well Josephson junction

We describe an apparatus designed to make non-demolition measurements on a Bose-Einstein condensate (BEC) trapped in a double-well optical cavity. This apparatus contains, as well as the bosonic gas and the trap, an optical cavity. We show how the interaction between the light and the atoms, under appropriate conditions, can allow for a weakly disturbing yet highly precise measurement of the population imbalance between the two wells and its variance. We show that the setting is well suited for the implementation of quantum-limited estimation strategies for the inference of the key parameters defining the evolution of the atomic system and based on measurements performed on the cavity field. This would enable {\it de facto} Hamiltonian diagnosis via a highly controllable quantum probe.Comment: 8 pages, 5 figures, RevTeX4; Accepted for publication in Phys. Rev.

Adaptive Glass Panels using Shape-Memory Alloys

Due to the growing application of laminated glass panels in building facades and roofs, tending towards the minimization of frameworks, substructures and supports, technological solutions based on the use of glass panels with increasingly wide dimensions and modern design principles are becoming more frequent. The growing use of structural glass applications is leading to \u201clighter\u201d and \u201csmarter\u201d optimized design solutions. The design of such applications greatly depends on the material mechanical properties of their structural elements and on their sensitivity to ambient and loading conditions. This is the specific case of laminated glass, where a temperature and time loading sensitive interlayer is generally used to bond together two (or more) glass panes with brittle behavior and rather limited tensile resistance. In this research paper, a novel adaptive glass panel concept is developed by using shape-memory alloy (SMA) cables, and assessed by means of Finite-element numerical studies and experimental validation. Based on the case study of an existing laminated glass roof panel, several geometrical configurations of practical interest are investigated. A key role in the proposed approach is the application of external pre-stressing based on the Joule heating of the SMA bracing system. The structural efficiency of the cable system is emphasized by taking into account the effects of ordinary wind pressures and temperature variations. Due to the innovative adaptive control system, as shown, the structural performance of traditional laminated glass panels can be enhanced, e.g. optimized in terms of maximum displacements and stresses in the glass, as well as in the overall dimensions and thicknesses of the glass panes

Advancements in Design and Analysis of Protective Structures 2019

This ADAP 2019 Annual Issue follows and extends the ADAP Special Volume of 2018 and aims at providing a further insight into current trends and recent advancements in design and analysis, experimental testing, and modelling of protective structures

Nitrous Oxide and Methane Dynamics in a Coral Reef Lagoon Driven by Pore Water Exchange: Insights from Automated High‐Frequency Observations

Automated cavity ring down spectroscopy was used to make continuous measurements of dissolved methane, nitrous oxide, and carbon dioxide in a coral reef lagoon for 2 weeks (Heron Island, Great Barrier Reef). Radon (222Rn) was used to trace the influence of tidally driven pore water exchange on greenhouse gas dynamics. Clear tidal variation was observed for CH4, which correlated to 222Rn in lagoon waters. N2O correlated to 222Rn during the day only, which appears to be a response to coupled nitrification‐denitrification in oxic sediments, fueled by nitrate derived from bird guano. The lagoon was a net source of CH4 and N2O to the atmosphere and a sink for atmospheric CO2. The estimated pore water‐derived CH4 and N2O fluxes were 3.2‐fold and 24.0‐fold greater than the fluxes to the atmosphere. Overall, pore water and/or groundwater exchange were the only important sources of CH4 and major controls of N2O in the coral reef lagoon

“Narrativas Coloniales de la Historia Ambiental. Un balance hacia la Decolonialidad como nueva epistemología”

Desde hace tiempo la narrativa de la historia ambiental ha sido diseñada desde parámetros eurocéntricos en cuanto a su mirada al territorio como objeto de apropiación antrópica. El Capitaloceno como Sistema Global de destrucción ambiental se ha cimentado en ese eje epistemológico. Asistimos al reto de la mirada al reconocimiento de las aportaciones realizadas pero también hacia la construcción una narrativa decolonial con la que construir nuevos sujetos de nuestras epistemes y de los procesos de diseño comunitario de procesos hacia la sustentabilidad comunitaria. Para este relato tomamos en consideración las tramas en las que se ha construido la historia ambiental tanto en el ámbito de producción académica europea como norteamericano (de McNeill a Hughes, transitado por R. Grove) para concluir con una propuesta de reconceptualización de la propuesta decolonial aplicado al campo de los estudios socioambientales