1کارشناس ارشد تکنولوژی معماری، دانشکده معماری و شهرسازی، دانشگاه هنر اسلامی تبریز، تبریز، ایران
2استادیار معماری دانشکده معماری و شهرسازی دانشگاه هنر اسلامی تبریز، تبریز، ایران
3استادیار معماری دانشکده معماری و شهرسازی دانشگاه هنر اسلامی تبریز، تبریز، ایران-نویسنده مسؤول
در دهه های اخیر سق فهای باز و بسته شونده به دلیل قابلیت های آن ها در دستیابی به یک معماری انعطاف پذیر و پویا مورد توجه معماران و مهندسان قرار گرفته است. مشارکت انواع ساختما نها از جمله مرا کز ورزشی، استخرها در ایجاد یک معماری پایدار، تطبیق پذیری با شرایط محیطی، کاهش مصرف انرژی، و پاسخگویی مناسب به الزامات عملکردی یک بنا در جهت آسایش کاربران آن، استفاده از این گونه سقف ها را در فضای معماری افزایش داده است. ساخت بسیاری از این بناها به دلایل سازه ای و زیباشناسی با انواع فرم های منحنی ساخته می شود. از سوی دیگر، طراحی سقف های باز و بسته شونده بر روی سقف با سطوح و سازه های منحنی به سبب ماهیت ظاهری آن ها نسبت به سطوح مسطح پیچیده تر می باشد. در این مقاله سعی شده است که الگویی از نحوه باز و بسته شدن سقف به همراه مجموعه ای از ساختار سازه ای و مکانیزم مکانیکی مناسب به عنوان استخوان بندی سازه ای و حرکتی که قابلیت استفاده در سطوح منحنی را داشته باشد، ارائه گردد. ایده طرح استفاده از میله های متحرک بر روی سقف با سطوح منحنی و قوسی با دهانه متوسط و حرکت دورانی آن ها می باشد.
Propose of movement pattern for curved retractable roofs with using of movable bars
Horizontal development of the cities has resulted in much destruction environmentally and economically. Two of the major consequences of such destruction is imbalanced development and inappropriate application of lands in the cities that are referred brownfield in this article. Brownfield in the urban planning jargon, a brownfield site (or simply a brownfield), is a type of land formerly used for industrial purposes or some commercial applications. The brownfield concept was first introduced by the British government and was used in accordance with the sustainable development policies which is mostly focused on the environmentally polluted lands. In the last two decades, redevelopment policies of brownfield as a crucial practical solution for preventing disperse growth of cities and also supporting the concentrated growth of cities have been attracted more attention. The main features of the brownfields are: -1 Pollution: each land in which an environmental complication has the occurrence probability. -2 Empty and leaved without using and in general lands and properties that their activities have been closed or not been used anymore. Of course, some of the terms that must be separated from the brownfield areas are: greenfields and grayfields. Greenfields are those lands that previously has not been developed and often are rural or suburban. These green sites are located in the edge of small or large cities and have better accessibility and more palatability with additional space for future development. The term grayfield, was defined in 1998 by new urbanism congress. Unlike the famous terms of greenfields (the rural undeveloped) and brownfields (polluted urban sites), the gray lands are called to the large undeveloped sites that have good reasons for redevelopment. The term of grayfield can be used to describe any kind of redevelopment that significantly is not polluted. But regarding the importance of environmental protection and sustainable development and realization their policies, it is essential to eliminate or reduce the environmental pollutions purposefully to achieve the redevelopment of brownfields. For the sake of importance and novelty of the subject, redevelopment of Brownfield with the objective of efficient applications of lands in cities and reducing the environmental pollution and also improving the social-economical context of these fields is the subject of this article. Brownfield of Kan stream in Tehran was selected as the case study. The field was selected as it is one of the few major barren Brownfield in Tehran. They are not only in the leaved brownfields but also regarding the river-valley nature, the fields has specific ecological and tourism features. Unfortunately, due to lack of planning and management, these brownfields have been converted to the locations of rubbish depot and uncontrolled polluted waters and therefore infected with the environmental pollution. The methodology of this article is descriptiveanalytical using library studies. After studying the theoretical framework, defining features of brownfield, literature review, objectives and the importance and of these fields, the redevelopment process of Kan stream Brownfield are presented. Finally, the conclusion and analysis of the actions are conducted in redevelopment of brownfield with social, economical and tourism approach. After comprehensive studies, in order to determine the kind of landuses in Kan brownfields, establishing a national and even an international performance scale park is designated as the planning vision. In this context, the objectives of the redevelopment planning process Kan brownfield included: creating a touristic space to enhance the region›s tourism identity, planning with emphasis on providing recreational services for all social classes, such as children, elderly people and women and people with disabilities (all divisions with regard to sex, age and physical aspects), strengthening of the relationship between people and nature and to replacing normal social activities and improvement environmental conditions; Developing ecotourism in urban environment regarding and it s benefits beyond natural landscapes, enhancing green space for per capita in Tehran city and attainment to the standard limits for environment qualities by using marginal lands and rivers sanctums.steel plates. In addition these bars are pre- tensioned by means of cable passing through them in order to behave properly to the applied forces. The way that the bars are moved through the retraction process and the function of the building effects on the selection of the covering materials. In this structure, as the distance between the bars is changed during the deployment process it is required to use a flexible but strong material that can resist repeated retraction. Therefore, a flexible membrane that is strong enough during movement and has a proper foldability such as ETFE is one of the best alternatives for covering the roof. ETFE is also able to penetrate enough light inside of the building when the roof is in fully closed position and this in turn reduce the energy required for running the building. The membrane is also attached to the bars though the slots that have already been created during fabrication and is fasted by means of pinned curve plate. This is also worth to mention that in this structure, the placement of the moveable components underneath the covering material support the whole structure even in severe weather conditions. Therefore, this increase the life cycle of the system and decrease the maintenance cost. In summary, this paper proposes a new solution for a retractable curved roof system that can not only be transformed from an open to closed configuration but is also able to support itself structurally even during movement and transformation. In other word, the structural and transformable components are integrated and are able to make the whole structure stable during transformation.
1-Schumacher, M. Schaeffer, O. and Vogt, M; 2010; Move- Architecture in Motion- Dynamic Components and Elements; Birhauser Architecture; Germany. 2-Asefi, M & Fakourian, F. 2013; Changeable Mechanical Curtain Wall for Educational Buildings; proceeding of International conference on Adaptation and Movement in Architecture, Ryerson University, Toronro, Canada, pp.223-213 3-Ishii, K. 2000; Structural Design of Retractable Roof Structures; WIT Press; Boston. 4-Goppert, K. 2007;A Spoked Wheel Structure for the World’s largest Convertible Roof – The New Commerzbank Arena in Frankfurt, Germany; Journal of Structural Engineering International: 287-282. 5-Temmerman, N. et al, 2014; Lightweigh Transformable Structures: materializing the Synergy between Architectural and structural Engineerin in Mobile and rapidly Assembled Structures IV (Edited by Temmerman and barbera); WIT Press, UK 6-Masubuchi, M. Bogle, A. Schlaich, V; 2010; Study of retractable membrane roofs folding to the perimeter; International Conference of IASS; China. 7-Huntington, C; 2004; the Tensioned Fabric Roof; ASCE Press.