The vibration performance of pedestrian structures attracts the attention of several studies, especially with respect to unfavorable operational conditions or possible damage scenarios. Given a pedestrian system, specific vibration comfort levels must be satisfied in addition to basic safety requirements, depending on the class of use, the structural typology and the materials. To this aim, guideline documents of the literature offer simplified single-degree-of-freedom (SDOF) approaches to estimate the maximum expected vibrations and to verify the required comfort limits. Most of these documents, however, are specifically calibrated for specific scenarios/structural typologies. Dedicated methods of design and analysis, in this regard, may be required for structural glass pedestrian systems, due to their intrinsic features (small thickness-to-size ratios, high flexibility, type and number of supports, live-to-dead load ratios, use of materials that are susceptible to mechanical degradation with time/temperature/humidity, etc.). Careful consideration could be then needed not only at the design stage, but also during the service life of a given glass walkway. In this paper, the dynamic performance of an in-service glass walkway is taken into account and explored via field vibration experiments. A set of walking configurations of technical interest is considered, involving 20 volunteers and several movement features. The vibration comfort of the structure is then assessed based on experimental estimates and existing guideline documents. The intrinsic uncertainties and limits of simplified approaches of literature are discussed, with respect to the performance of the examined glass walkway. In conclusion, the test predictions are also used to derive “perception index” data and scales that could support a reliable vibration comfort assessment of in-service pedestrian glass structures.
Given a series of intrinsic features of structural glass systems (i.e., material properties, type of restraints, operational conditions, etc.), special care should be spent at the design stage, to ensure appropriate fail-safe requirements, but also in the service life of these innovative building components and assemblies. In this paper, the dynamic characterization of simple monolithic glass elements is presented, based on non-destructive laboratory experiments and Operational Modal Analysis (OMA) techniques, including Finite Element (FE) numerical simulations, classical analytical models, and video-tracking approaches. It is shown, in particular, how the actual restraint condition (i.e., flexibility of supports, with respect to ideal boundaries) can affect the vibration parameters of a given glass member (frequency and damping capacity). This turns out in possible variations of its overall structural performance, including stress-strain-related effects, hence suggesting the need for even further dedicated studies and methods for the reliable analysis and design of structural glass assemblies and complex systems under dynamic loads.
In current design practice for seismic resistant steel braced frames, general rules and standard provisions are\ud aimed to ensure a structural behaviour for beam-to-column joints of non-braced spans as close as possible to\ud perfect hinges. This is done to prevent any kind of interaction with the bracing systems, in particular under\ud horizontal loads. However, the global performance of composite joints is markedly affected by the structural\ud interaction between the concrete slab and the steel components and - especially during seismic events - struts\ud can occur in the slab at the beam-to-column intersection.\ud In this paper, the possibility of realizing a composite joint that behaves as moment-resisting under gravitational\ud loads and essentially as hinged under horizontal loads is investigated. Aiming to assess the actual slab-interaction\ud effects on the overall response, a full 3D Finite Element (FE) model representative of a beam-to-column composite\ud joint taking part of a braced frame is described in ABAQUS and validated towards past full-scale experiments.\ud A parametric study is hence proposed, by accounting for three geometrical configurations, being characterized by\ud (i) isolated slab with absence of rebar continuity (i.e. fully disconnected slab and steel joint only), (ii) presence of\ud slab with partial column interaction (i.e. isolated slab and continuity of rebar), (iii) presence of fully interacting\ud slab. It is shown that, if properly detailed, a joint with isolated slab and continuous rebars can be used in nonbraced\ud spans of composite braced frames without affecting the behaviour of the bracing system (i.e. as in\ud presence of a hinge). Nonetheless, the composite beam can be designed as continuous on multiple supports\ud under vertical loads, hence leading to a reduction of the steel cross-sectional size
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.