بررسی نقش محرک های مدیریتی-اقتصادی در کاهش دوره بهره وری ابنیه نمونه مورد مطالعه: شهر تهران

امروزه موضوع مدیریت تقاضای تخریب و ساخت به عنوان چالشی برای چگونگی حفاظت از ساختمان های بادوامی که همچنان قابل استفاده برای زندگی و فعالیت هستند، تبدیل گردیده است. اهمیت این موضوع از آنجایی است که بر بهره وری شهری موثر است. بهره وری شهری، مفهومی کلی است که شهر و تمامی کارکردهایش را در برمی گیرد. ساختمان از جمله عناصر کلیدی در ساختار اقتصادی و همچنین فضایی شهرهاست و نقش تعیین کننده ای در مدیریت و توسعه شهری دارد و بهره وری آنها در مفهوم مدیریت تقاضای تخریب و نوسازی به معنای بهره برداری از تمام ظرفیت های سازه ای و کالبدی آنها تعریف می شود. ساختمان همواره یکی از اولویت های سرمایه گذاری در شهر تهران بوده است. این در حالی است که الگوهای مدیریتی و نظام حقوقی حاکم، فاقد ضوابطی برای مدیریت تخریب و ساخت است. این مهم از آنجایی نشات می گیرد که فواید سریع الوصول حاصل از تخریب و نوسازی، هزینه های بلندمدت ناشی از آن را پنهان نموده است. براین اساس، در این پژوهش با اتکا بر چند پیش فرض و بهره گیری از روش نمونه گیری چند مرحله ای،چهار هزار و  526 نمونه در سطح مناطق شهر تهران انتخاب و تحلیل روند تغییرات آن را با توجه به مبانی حقوقی و اقتصادی کلان، مورد بررسی قرار می دهد. نتایج حاصل از این تحلیل نشان می دهد که غلبه ارزش زمین بر ساختمان، اصلی‌ترین محرک تخریب و نوسازی ساختمان ها در شهر تهران است؛ به گونه ای که مناطق برخوردار از بافت فرسوده، لزوماً سهم بیشتری از صدور پروانه تخریب و نوسازی نداشته اند. همچنین دوام و سن ساختمان، مانعی از سوی ضوابط حقوقی مدیریت شهری به منظور جلوگیری از تخریب ایجاد نمی کند. این در حالی است که تخریب ساختمان های واجد ظرفیت نگهداشت الزاماً برای مدیریت شهری منفعتی ایجاد نمی کند. بنابراین ایجاد تغییر در تعاریف و  ضوابط در ایجاد ارزش افزوده و افزایش تمایل به نگهداشت ساختمان از سوی مالک ضروری است.

evaluation of managerial-economic drivers in decreasing buildings’ productivity period (case study: tehran)

introductionmanagement of the demand for destruction and reconstruction has been known as a challenge to preserve durable buildings which are still available for use as places to live in or perform activity. it is also effective on urban productivity, a general concept that contains all the urban functions. buildings make up the main factor in specification of the economic and spatial structure in a city. they have a determinative role in urban management and development, and their productivity is interpreted as the use of all the physical and structural capacities. therefore, it can be claimed that buildings are important in urban productivity.buildings are a priority in the investment made in cities, particularly in our country. however, managerial patterns and legal system are not established based on the roles and rights to manage the demands for destruction and reconstruction. this results from the readily-available benefits of destruction and reconstruction, which conceal the costs. due to the importance of buildings as a national value and given the concept of sustainable development, it is necessary to analyze the statistical trends and study the different factors which impact the public tendency to destroy and reconstruct buildings.theoretical frameworkan essential approach to protection of durable buildings concerns infill development. this approach, which originates from sustainable development, includes one of the most serious activities performed to preserve durable buildings: adaptive reuse of buildings which exhibit the capacity to be preserved (based on their forms and functions). in other words, adaptive reuse of buildings is based on their capacities and characteristics.therefore, the main approach to durable building preservation stems from sustainable development. return to life cycle is the relevant pattern which can increase the efficiency period of a building. urban efficiency is a way to improve urban management.it is worth mentioning that urban land, as a basis for creation of buildings, has a remarkable role in the attempt to achieve urban efficiency. the city and the functions which are created there are defined on that basis.methodologyin this research, statistical information on destruction and reconstruction permits granted in a twenty-year period has been analyzed. in addition, 4526 cases have been selected as durable buildings using random sampling. moreover, an evaluation of the income codes of tehran municipality in the defined period has been considered. therefore, this research has studied the public and managerial trends concerning the preservation of durable buildings and the relevant side effective factors.result and discussionthe results of this investigation revealed that the value added due to destruction and reconstruction is the most important factor that encourages people to make such demands. however, an analysis of urban management income shows that destruction of durable buildings has no great impact thereon. it seems that a number of modifications in urban terms and restrictions need to be considered in durable building preservation. in this case, one must consider definition of new methods for creation of value added to satisfy the owners of durable buildings in order to preserve them.conclusionthe factor that distinguishes this study from others is that it has focused on legal principles in management of the demand for destruction and reconstruction. moreover, failure in supervision and administration and management inconsistency have been identified as the most important factors in the decision to destroy buildings which have the capacity to be preserved. in other words, urban management does not provide appropriate techniques to manage the demand for destruction and reconstruction.in conclusion, the tendency to destroy durable