VULNERABILITY STUDY OF EARTH WALLS IN URBAN FORTIFICATIONS USING CAUSE-EFFECT MATRIXES AND GIS: THE CASE OF SEVILLE, CARMONA AND ESTEPA DEFENSIVE FENCES

Abstract

The objective of this paper is to develop a new methodological model to assess the vulnerability of defensive

remains in rammed earth walls in historical centers. To do this, the vulnerability index based on cause-effect

matrix has been adapted for constructions which main component is rammed earth walls and combined

with a Georeferenced Information System (GIS).

Medieval defensive fences have been studied in three historical centers in the province of Seville (Carmona,

Estepa and Seville). 20 sections belonging to medieval rammed earth walls fortifications (10th -15th century)

have been analysed. In the case of Carmona, the bases of the walls are from the Carthaginians period (3rd

century BC). The sections were divided into 199 minimum units of analysis (MUA), with walls, towers,

gates, shutters and fortresses. 2450 m of earth walls were studied in the three cities. The tools used to assess

the vulnerability index were Leopold matrixes and cataloguing cards filled out after onsite inspection. As a

result, a descriptive study of weathering forms that affect the structures and a vulnerability index that

identifies the most vulnerable structures is presented. The information gathered is very useful in decision

making and prioritization of strategies in the preservation of urban heritage environments.