Dissertations/Theses - Department of Architecture

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Subject: search.filters.subject.Architecture-Environmental aspect -- Dhaka City

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    Study on potential integration of greenway on urban street canyon at planned residential area of Dhaka city
    (Department of Architecture, BUET, 2018-09-29) Zarrin Tasnim; Joarder, Dr. Md. Ashikur Rahman
    Orchards and meadows featured ancient Dhaka city. Gradually over population has turned it into a concrete jungle. Rapid urbanization replaces foliage with edifices and produces microclimate of higher air temperature or Dry Bulb Temperature (DBT) than rural surroundings. Outdoor temperature of Dhaka is 1-1.5 K higher than that of immediate regions. Thirty percent denizens of Dhaka commute 0-2.5 km on foot daily. Ample striders die in road accident in this pedestrian inimical city. Integrating greenways on the street canyons of Dhaka is an implicit remedy alleviating these delinquents. Tropical studies found that planted urban streets reduce DBT to the extent of 1-3 K. Greenways are linear open spaces built along lush green, stream or similar features for non-motorized users that ameliorate environment. This study concerns about the microclimatic impact of integrated greenways on street canyons at planned residential Dhaka. To unravel this quest, field study was steered at eight potential planted and bare street canyons at planned residential Dhaka. The microclimatic parameters were recorded from 10.00-18.00 hours at summer days using Thermo-Anemometer and Hygro-Thermometer. An existing bare street canyon was simulated from 08.00-20.00 hours using Envi-met. Greenway was integrated on idem bare model and simulated from 08.00-20.00 hours. Simulated maps were extracted through Leonardo. Field and simulation study were analysed to scrutinize the microclimatic impact of integrated greenways on the street canyons of Dhaka. This study reveals that greenways hold an immense cooling effect on street canyon microclimate of planned residential Dhaka enhancing pedestrian thermal comfort. The integrated greenway reduced DBT to the extent of 7.03-10.30 K, Mean Radiant temperature (Tmrt) 5.76-31.36 K and increased Relative Humidity (RH) 7.90-18.47%. This study unveils the role of integrated greenways on street canyons to lessen the outdoor DBT of Dhaka. This study escorts the urbanites towards a hustle and bustle free thermally comfortable relaxed outdoor walking trail through integrated greenway.
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    Study on the impact of building regulation on street morphology and ensuing microclimate in planned residential area of Dhaka City
    (Department of Architecture (Arch), 2015-04) Iftekhar Rahman; Ahmed, Dr. Khandaker Shabbir
    Cities have a tendency to transform through intensifying its land use in urban areas. Bangladesh is a developing country where the expansion of the capital city Dhaka is resulting in one of the mega cities of the world. Buildings are being built to accommodate the increasing inflow of population within this mega city. Recent studies reveal that the impact of urban heat island in Dhaka city is gradually increasing. Thus proper master plan is required for sustainable development and also to improve microclimate within urban areas. Microclimate within the streets is influenced by its morphological character, geometric pattern, orientation, built density and available green space. In residential areas of Dhaka, street morphology is an outcome of the neighboring built forms, usually controlled by building construction rules. The Metropolitan Building Construction Rules [BCR] introduced in 2006 with the application of Floor Area Ratio [FAR] with amendments in 2008 and further in 2013. FAR rule results increased building height, relatively smaller building footprint and potentially free ground floor resulting in an urban street canyon with uneven canyon walls. Thus the research examines the results of an investigation, how FAR impacts outdoor street microclimate with spatio temporal characteristics of the ambient climatic environment. Different microclimate parameters at pedestrian level were studied. Results from an intensive field survey were studied at locations of different street orientations in a planned residential area of Dhaka city. Computer based simulation results as well as observed field data were compared, statistically analyzed and examined in terms of street orientation, aspect ratio, building mass configuration. Comparisons of the present building regulation with the previous are made. Possible urban design considerations are discussed to enhance urban street microclimate for planned residential areas.