Evaluation of entrance design indicators of metro station in the historical context of Tehran city, according to considerations of Passive Defense

One of the most important challenges in historic areas and perhaps the most important concern in urban management involves the design of an appropriate transportation system for provision of better facilities with minimal intervention. It is therefore an inevitable necessity to provide access to a convenient, safe transportation system such as the subway in the historic, distressed area of Tehran, Iran given the high population density and accumulation of administrative, political, and other services in the area as well as natural and unnatural hazards, so that safety can be maintained, and service can be provided in case of a crisis. Important urban community centers throughout Tehran’s historic area, subway stations can be regarded as dual-purpose, used for temporary accommodation and emergency services in case of an unexpected event. Activities that can be carried out at a subway station include accommodation of citizens, storage of food, provision of emergency service, and transportation of the injured. Application of passive defense requirements to the design of subway station components is one of the most important ways of providing subway security in critical conditions. A subway station is composed of different components, with the entrance element intervening the inner and outer spaces as the first component. Location and design of the subway station entrance is an important task involving particular complexity as well as intricacy and requiring precise predictions. Therefore, this research needed to address two significant questions. Firstly, what indicators are involved in subway station entrance design in Tehran’s historic area given the architectural requirements and passive defense considerations? Secondly, to what extent have these indicators been utilized in the design of the subway station entrances in Tehran’s historic core, and which is the best station in terms of observation of the indicators? The aim of this qualitative applied study was to evaluate the subway station entrances at Tehran’s historic core in accordance with the standards and to determine the indicators for design of subway station entrances based on passive defense considerations. First, the intended indicators were extracted through a review of the domestic and international regulations, the most important being Article 21 of the Iranian Building Code and FEMA’s regulations. For a better understanding of the extracted indicators and acquaintance with the regulations in other countries as well as in Iran in subway station design, four subway station entrances in China, Brazil, England, and Canada and three in Esfahan, Mashhad, and Tabriz in Iran were analyzed as samples, where the above indicators were investigated. The extracted indicators were evaluated in Tehran’s District Twelve using the analytic hierarchy process (AHP), and the degree of importance (weight) for each of the criteria and options was calculated based on the above regulations using the Expert Choice software and a prioritization of the indicators based on the method of sensitivity analysis. The results indicated that the criteria distance from the entrance building to the main arteries and method of access to the entrances had the greatest and least impacts on subway station entrance design with relative weights of 0.205 and 0.027, respectively. On that basis, the Darvazeh Dowlat subway station entrance was identified as the best with five out of the nine standard indicators and a relative weight of 0.147, followed by the Baharestan, Khayam, Imam Khomeini, Panzdah-e-Khordad, Saadi, and Mellat subway station entrances.