Nature’s nations: the shared conservation history of Canada and the USA

Historians often study the history of conservation within the confines of national borders, concentrating on the bureaucratic and political manifestations of policy within individual governments. Even studies of the popular expression of conservationist ideas are generally limited to the national or sub-national (province, state, etc.) scale. This paper suggests that conservationist discourse, policy and practice in Canada and the USA were the products of a significant cross-border movement of ideas and initiatives derived from common European sources. In addition, the historical development of common approaches to conservation in North America suggests, contrary to common assumptions, that Canada did not always lag behind the USA in terms of policy innovation. The basic tenets of conservation (i.e. state control over resource, class-based disdain for subsistence hunters and utilitarian approaches to resource management) have instead developed at similar time periods and along parallel ideological paths in Canada and the USA

Finite-element analysis of post-tensioned SG-laminated glass beams with mechanically anchored tendons

Based on past experimental research results, this paper aims to investigate the structural performance of laminated glass beams with post-tensioned, mechanically anchored tendons, via extended finite-element (FE) simulations. The post-tensioned glass beam concept offers the advantage of providing a certain amount of initial compressive stresses in glass, hence resulting in a marked increase of the initial fracture load and in a rather appreciable redundancy, compared to typically brittle, unreinforced glass beams. Due to the presence of the post-tensioned tendons, a significant level of residual strength can also be guaranteed, thus resulting in a structurally efficient and safe design concept. In order to fully optimize the expected resistance and redundancy potentialities, however, careful consideration should be paid for a multitude of geometrical and mechanical aspects. In this research contribution, both full 3D and shell models are implemented for post-tensioned laminated glass beams. Based on validation of these FE models towards the past full-scale experimental results, the effects of several mechanical parameters are emphasized (e.g. steel tendon percentage, level of the applied pre-stressing force and the presence of possible geometrical imperfections) under room temperature and quasi-static loads. It is expected, based on the current study, that the examined design concept could be further developed and optimized.OLD Structural Desig

Laminated connections for structural glass components: a full-scale experimental study

The use of glass material for structural components has drastically increased in the last decade. Among others, a laminated connection is a type of adhesive joint that makes use of foil interlayer adhesive to transfer forces between glass and metal parts. In this work, the use of embedded laminated connections is studied as connection between glass beams. In particular, it is experimentally investigated the use of embedded connections laminated to make a moment joint between laminated glass beam segments. The mechanical behaviour of such glass beams with embedded laminated connections is studied under different loading scenario. Tests are performed under monotonic, creep and damage protocol. Different geometry and location of the embedded laminated connections are compared. The results of this work showed that embedded laminated connections represent an efficient means of load transfer between glass beams. It is observed that the choice of an appropriate geometry and location of the embedded connections can provide a substantial enhancement to the mechanical behaviour of the beam. In particular, a redundant and ductile structural behaviour of the moment connection can be achieved. Furthermore, results also showed that beams with embedded laminated connections are able to resist to severe damage scenarios and to sustain the applied load over time, even in the case of breakage of all glass panels.OLD Structural Desig

Reuse of glass bottles for structural columns

Container glass is omnipresent and reuse can be observed all around the world. It can even be reused for the construction of structural components for buildings of which several examples exist around the world. However, research on the reuse of glass for structural components seems lacking. Therefore, this paper investigates the potential of reusing glass bottles for the construction of structural columns. Firstly, the compression strength of artificially abraded glass bottles was investigated in compression tests, revealing a compression strength between 10 and 20 kN. Secondly, alternative assemblies of multiple glass bottles were tested in compression, to determine their suitability for constructing a column. Finally, an exemplary column prototype constructed of glass bottles is presented. From the findings it is concluded that it is feasible to reuse glass bottles for the construction of structural columns that could carry small scale structures.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Mechanic

The glass swing: a vector active structure made of glass struts and 3D-printed steel nodes

The majority of glass used in load-bearing structures is as planar elements. Some projects exist that use linear glass elements. This paper discusses in broad terms the design, engineering, and fabrication of a unique vector active glass structure consisting of glass bundles and partly printed steel connections. A structure was conceived that utilizes the glass bundles in a way that can be directly experienced by the users: a swing. To create a non-standard form for the swing, a structural optimization procedure was used. To realize the structure, a novel steel node was developed and produced using an additive manufacturing technique in steel. These novel applications have made the project innovation heavy, particularly considering the limited timeframe for its development and construction. Description is given of the several optimization techniques incorporated in the digital process, the assembly and testing of the glass bundles, and the manufacturing of the steel nodes by Wire and Arc Additive Manufacturing.Structural Design & MechanicsApplied Mechanics(OLD) MSE-