This literature study examines previous studies of the optical properties of snow, and attempts to tie them together with studies on the effects of shading on photovoltaic solar panels. The study presents some information on the general properties of snow, and ice including geographic extent and some conditions of snow and ice formation. General optical properties of snow are examined, such as reflectance (albedo) and spectral transmittance. Common transmittance profiles for snow covers are also examined. The study also presents some commonly understood effects of shading on photovoltaic panels, both in the form of uniform shading (weak light) and partial shading. Other snow-related aspects of operating a photovoltaic system are also brought up, such as snow loads and the risks posed by snowmelt, particularly in regards to building-integrated or building-applied photovoltaics. Common methods of addressing snow-related challenges are summarized, both on a material and an architectural level. Lastly, suggested future research paths are presented.
As the climate changes globally and locally, the built environment will be subject to different climatic exposure than in the past. Adaptation measures are required to ensure the long-term integrity and successful operation of the built environment. This study examines literature on climate adaptation measures for buildings through a scoping literature review. It is centered around the main journals in the field of climate adaptation of the built environment, then expanded to map the extent of scientific publications about climate adaptation in general. Studies that regard future climate scenarios have been of particular interest. The majority of the identified literature concerns climate change impacts on buildings in warm climates, with overheating being seen as the greatest challenge. Additionally, few empirical studies are found; most identified research is based on computer simulations or literature reviews. The volume of research on the consequences of climate change on buildings in cold regions is surprisingly small, considering the pecuniary stakes involved. The predictions of climate scenarios suggest regulatory/policy measures on climate adaptation should be taken as quickly as possible to avoid greater costs in the future. However, further research into future scenarios is also essential.
Green and blue-green roofs are emerging as an increasingly popular feature of rooftops, particularly in urban areas. Particular problematic conditions render their usage complex in the Nordic countries. In order to ensure that green roofs are built durable and with the service life expected of them, it is important to know all the relevant factors surrounding their construction and operation. A scoping study was conducted in order to gain an overview on green roof research and available scientific literature. One hundred articles of particular interest for Nordic climates were retrieved and their findings summarized. It is found that the vast majority of green roof research has been conducted on a theoretical basis, or with practical measurements on green roof test beds or isolated components. There is scarcely any literature on the operation of full-scale, building-implemented green roofs, and no articles were found on the building technical performance of aged green roofs. These knowledge gaps indicate a major risk factor in green roof operation, as their performance and integrity over time has not been documented. This despite the fact that green roofs have been implemented and in operation worldwide for decades.
The Gullfaks C concrete platform was successfully installed on a soft soil site in 1989. This was the first time the new foundation concept of skirt piling i.e. very deep concrete skirts acting as piles, was implemented for a gravity base structure. The platform foundation consists of 16 large diameter skirt piles penetrating 22 meters into the seabed. Installation of these "piles" was achieved by platform weight and underbase suction. The platform weight was initially carried as base contact pressures. A soil strengthening scheme enabled full weight of the platform to be carried by the skirtpiles within 3 months. Through this first skirtpiled platform installation, the concept of skirt piling should be recognized as a proven design. INTRODUCTION The Gullfaks C platform installed in May 1989 is the largest and heaviest offshore concrete structure ever built. Designed for 220 m water depth it has a displacement of more than 1.4 million tonnes and represents a total investment of $ 2 billions. Contrary to previous gravity base structures, the Gullfaks C platform was offered one of the most complex seabed conditions in the North Sea to date. The upper 45 meters of soils consist predominantly of normally consolidated soft clay and loose clayey and silty sands with interbedded dense sand layers, see Fig. 2. The combination of a heavy gravity structure and soft soils called for a new foundation solution:–skirt piles through soft soil layers, and.–strength improvement of soils below the depth that could be reached by skirt piles. The strength improvement was achieved through an acccelerated soil consolidation by means of a large soil drain system comprizing more than 800 single filters and a total filter area of 1600 m2 The system was operated with suction through the first summer season. In this period 8000 m3 of ground water was extracted from the foundation soils. The platform foundation base area amounts to 16000 m2 The foundation is made up of 1400 running metres of concrete skirts penetrated 22 m into the seabed. The skirt piles consist of 16 circular concrete cells of diameter 28 m and wall thickness 0.4 m, see Fig. 1. After soil strengthening by artificial drainage, the operational platform submerged weight of 500.000 tonnes is mainly transferred to the soil as skirt tip resistance and skirt wall friction. This will reduce the future platform settlements significantly. The skirt penetration driving force was provided by platform water ballasting and underbase suction. FOUNDATION DESIGN ASPECTS AND INSTALLATION PRINCIPLES Foundation design aspects There are four major foundation aspects of the GBS foundation. These are:–Skirt penetration resistance–Foundation stability–Foundation load distribution–Platform settlement Foundation stability of Gullfaks C could theoretically be obtained in several ways, e.g. by large base area, very deep skirts or"stronger" soil. The relationship between these parameters are shown in Fig. 3. At the design stage, it was apparent that any realistic solution would have to be based on much deeper skirts than for any platform before.
As climate change brings an increase in torrential rain events in Nordic climates, new technologies are developed to manage stormwater. Blue-green roofs are constructed as a means to reduce the runoff of stormwater from roofs and reduce the risk of urban flooding. However, compared to conventional roofs, blue-green roofs represent different construction and operation conditions, which may affect the long-term integrity of the roof. The purpose of this research is to understand the variety of perspectives on how different actors perceive and manage quality risks related to blue-green roofs—that is, the probabilities and consequences of defects. The quality risks of blue-green roofs have been investigated through document studies and interviews with actors in the Norwegian building sector. Data have been collected from actors across the building sector to map differences in how risk is managed from several perspectives. The findings show that actors view quality risk in very different ways. While building owners are primarily concerned with the quality of the finished product, the primary concern of other involved actors may be to ensure that eventual defects cannot be attributed to their own activities. The efforts of the various actors to reduce the risks in their own activities may not necessarily reduce the risk of defects in roofs. To ensure a more comprehensive management of quality risk in blue-green roofs, it is necessary to consider the perspectives and incentives of all involved actors. This way, a framework could be developed as a feasible tool in blue-green roof projects.
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.