Investigating the role of open spaces and public buildings for earthquake vulnerability reduction in old Dhaka

Abstract

No one can prevent nor accurately predict earthquakes early on and that actually cause sudden death and destruction at a large scale. This certainly makes such an extreme event a part of urban agenda and more crucial for an unplanned city like Dhaka. This sort of extreme urban event should be taken as a prime consideration while designing in densely populated areas, particularly in old Dhaka in order to explore and arrive at coherent urban design solutions. Old Dhaka, the historic part of Dhaka city, is more vulnerable to any imminent earthquake due to its high population density, unplanned development, non-engineered buildings, contiguous building pattern, narrow streets withlow level of accessibility, lack of open spaces coupled with least response and recovery capabilities. In order to reduce the earthquake vulnerability, the first and foremost task is vulnerability assessment before designing any guidelines for rescue and recovery. Therefore, this research attempts to identify the scenario of vulnerability of sample area of old Dhaka by assessing its built environment. After a major earthquake, the open space network becomes a kind of ‘second city’, providing multiple complex functions such as gathering and shelter, the distribution of goods and services, temporary inhabitation etc. Therefore, a designed network of open spaces and public buildings not only significantly contribute to the quality of everyday urban life, but also has the latent capacity to act as essential life support and an agent of recovery in the event of an earthquake. Therefore, the aim of this thesis is to examine the role of open spaces and public buildings for earthquake rescue and recovery process in old Dhakathrough a theoretical framework and spatial analytical procedure. The main concept within the framework is to develop an accessibility model regarding rescue and recovery for old part of Dhaka city. This study revealed that open spaces and public buildings in old Dhaka are useful elements of rescue and recovery for an earthquake post management process and planning. But, detail planning guidelines incorporating the open spaces and public buildings (emergency shelters) in an existing urban setting is stillless intervened research arena. Therefore, space syntax technique, geographic information system and field survey were used as triangulation methods for analysing the accessibility network in a prevailing urban setting in old Dhaka. A sample area of old Dhaka was used as a macro level case study for applying the suggested methods. Furthermore, this research analysed the study area at micro level in order to design the guidelines for safest evacuation model at neighbourhood scale. The results showed that the accessibility network model incorporating open spaces and public buildings could be a starting point for effective rescue and recovery in existing urban settings and can be applicable at both city and neighbourhood scale. Besides, the proposed ideas may further impart awareness among the future design professionals.