Architecture, Structures and Construction最新文献

There is a certain level of chaos and disruption associated with the construction process. When construction becomes associated with infill urban development, it has additional negative realities as it impacts the ability of those living and working around the construction site to live a normal life, often for a significant length of time. How can the choices we make in terms of structural systems and construction methods serve to lessen that impact? This paper focuses on aspects of the construction process that pertain to choices in structural systems (mass timber, steel and reinforced/precast concrete) to create a practical (qualitative) guide towards lessening their social and environmental impact in an urban setting. Lessening the impact of construction also feeds naturally into existing objectives in sustainable design assessment tools which look for waste reduction, minimization of light pollution and the containment of processes on site.

The paper describes the physical realisation of a 3D-concrete-printed, mortar-free, unreinforced masonry arched footbridge, designed for disassembly and reuse. The paper also details the novel integrated design, engineering and fabrication framework and the manufacturing and assembly processes used for the project. The research, motivated by the rapid growth in large-scale 3D concrete printing (3DCP), addresses the current lack of both design tools and integrated design-to-production solutions. It is guided by the insight regarding the applicability of design and analysis methods used in unreinforced masonry to large-scale, layered 3D printing with compression dominant materials such as concrete. Thus, the underlying computational framework and integrated design environment further extends and adapts advances in the computational design and analysis of unreinforced masonry structures to 3DCP masonry blocks. Adopting an unreinforced masonry paradigm for the design of 3DCP structures can make it possible to (i) reduce the amount of concrete used by allowing precise placement of concrete only where needed along the compressive flow of forces, (ii) reduce the amount of steel needed by reducing tensile and flexural strength requirements through a compression-appropriate design of both the global, shape and the block discretisation, and (iii) reuse components, repair the structures and recycle materials more easily. This paper builds on the relevance of the computational masonry paradigm to both delivering the ecological promises of 3DCP and to the development of a 3DCP-specific, design-to-production toolkit.

The urgency to rapidly reduce carbon emissions of the built environment make embodied carbon (EC), and thus material decisions, central to architecture’s most ambitious ecological goal. Structural systems are often the most durable and consequential to upfront EC in new construction. Although durability is critical to reducing EC in buildings in the long term, it may be at odds with the short-term goal to reduce resource consumption. This research closely and systematically examines the trade-offs between lower-carbon structural systems needed in the short-term and the durable systems needed to achieve long-term sustainability, functional adaptability and cultural significance. Specifically, this study evaluates the feasibility of using carbon-sequestering biomass to replace the more carbon-intensive structural materials that are more commonly used in buildings designed with extraordinary requirements of durability. The perceived conflict between durability and sustainability calls for more nuanced methods of analysis that consider the role of a building’s service life in EC reduction, and can augment the capacity of Life Cycle Assessment (LCA) to simultaneously consider the architectural impacts of material decisions. The methodology consists of fully redesigning the structure of an existing building with complex demands of sustainability and durability, and performing LCA for scenarios of equivalent architectural qualities, to retrospectively compare and analyze alternative low carbon futures in a context that only real projects can provide. The findings provide a more nuanced understanding of a near future when taller mass timber structures may leverage requirements for increased fire protection, robustness and durability to simultaneously achieve larger and longer-term carbon reductions.

Abstract

Among the approaches of circular construction, the reuse of buildings can be considered the most desirable as it leaves a large portion of embodied carbon untouched. At the same time, it also minimises the energy effort of modifying, transporting or reprocessing the components. However, its underlying mechanisms and boundaries are largely understudied as convertibility and adaptability are currently at most rudimentary integrated neither into legal frameworks nor the architectural or technical design process in practice. In this paper, a new methodology is presented based on the models of Brand (1995) and Leupen (2006) to describe the adaptability of buildings as a function of their structure. The model also includes the circulation system and the specific areas of use. In the discussion of structurally determined usability, several concepts are introduced, such as structural porosity, pockets of use, diversity of pockets of use and diversity of circulation. The method is applied to three case studies that offer different adaptabilities due to their structural configurations. As the permeability or structural porosity of slabs significantly contributes to the usability throughout the structure’s lifetime, ribbed slabs seem to increase adaptability. Together with the spatial structural porosity of the grid, it proves to be a helpful criterion for good appropriability and convertibility. The method proved beneficial in understanding the dependence of the change of use on a given structural configuration. It helps to name the essential aspects, objectify them and make substantially different buildings comparable.