Alfama district is Lisbon’s oldest district on the mortar-shaped slope. The place escaped catastrophic damage from the 1755 Lisbon earthquake, and had been invaded repeatedly by different ethnicities. There is a unique landscape, a lot of stairs, narrow alleys and high-density housing, which characterize such a historic district is located in the center of Lisbon. However, in both Portugal and Japan, few studies have focused on the district, and little is known about the street structure. Then, we decided to research the actual condition and characteristics of its street structure.
As method, first, we define “stairs” and “retaining walls” as a common component on the slope. Then, we consider the “small square” as a unique component of the district. From the above three viewpoints, we study the street structure.
The purpose of this study is to clarify (1) the characteristic of shape of stairs and retaining walls by actual measurement survey, and (2) the network structure of the street on the mortar-shaped slope.
Results are summarized in the following statements.
1）a. Except small stairs, the shape of stairs is categorized as "large width stairs" and "narrow width and long stairs"
1）b. There are three shapes of retaining walls: small one that flatten the small square or pertain to stairs, long and low one that connect the road or crossroads, and the huge ruins that is named “Cerca Moura”.
2）The street of Alfama district has been replaced by one-way road with traffic regulation system, passage of invading vehicles and public elevator. Additionally, the small square with stairs or retaining walls has an important role as a branch point of the semilattice network.