Marrakech was founded in 1062 during the Almoiravide kingdom (1060-1147) by the Sultan Youssef Ben Tachfine who had protected it with a defensive wall, which had never stopped to be extended according to the city’s enlargements, in particular during the Almohade (1145-1248) et Saadien (1554-1659) kingdoms. Presently it is a fabric of 19 km in length, of 6/8 meters of height and a relatively constant thickness of 0,6 meters. It is provided with nine doors which give access to the various agricultural areas of the region, with around 200 guard little towers, located approximately at any 35 metres.
The walling is built with pisé, a construction technique which is made up by compacting, into a formwork, various following layers of rammed earth in association with at least some whitewash. The cohesion of this natural concrete is ensured by the clay, so that the other components (river sediment, sand and gravel ) can create the frame which can resist to compression and cracking. This material’s use offers a lot of advantages regarding its cost, easy and speed execution and its optimum characteristics of thermal and acoustic insulation. On the other hand, its solidity and durability are strongly dependant on the ensured protection from water action.
Actually, the main source of the Pisé vulnerability is due to its high sensitivity to the water action (streaming, infiltration, splashing up, rain). The material earth, multiphase, porous and permeable, is made up with a solid matrix and some empty spaces which can hold a lot of water under any shape (solid, liquid or vapour), so allowing its circulation. The latest can occur, under the gravity effect of the water at the liquid state, with the major effect of phenomena of climbing-capillarity, which affects the ground floors and creates hazard for the stability of the structure; or even under the shape of vapour, it can be moved by the action of temperature and/ or pressure gradient.
The material chosen for the restoration should then have imperatively the same properties of the water circulation. Conversely, a barrier will be established which will trouble and hinder the circulations, can hold the water accumulation in the interface between the two materials, getting, as consequence, the rapid showing of reject phenomena.
003_VIEW_ The Air as Parameter for Designing Man’s Space
FOCUS ON AIR AND ENVIRONMENT
011_ From the Chimney to the Air Conditioning in the Mediterranean Buildings
Sabriela Kazazi, Fani Vavili
016_ From the Redrawing of the Papyri to the Paradigms of Passive Ventilation in Architecture
Adriana Rossi, Luis Palmero, Armando Di Nardo
023_ Impact of Natural Ventilation Options on Architectural Synthesis. Floor Plan, Section, Façade
Anastasia D. Stavidrou
029_ Ventilation Performance in Semi-buried Buildings in Greek Architecture
034_ Ventilation in patient’s room
042_ The Wind as a Musical Mapping Tool of the Urban Environment in the Mediterranean Area. The Example of the City of Thessaloniki, Greece
Dimitra Sideridou, George Sideridis
STUDIES AND RESEARCHES
046_ Exercises in Sustainability: Another Case Study
Anca Mitrache, Anca Mihaela Costantin
050_ An Approach to Assess Urban Resilience to Flood Risk Through Spatial Analysis
054_The Restoration of the Pisè Heritage: Experienced Results from Safeguarding Operations for the Marrakech Walling
Khalid Rkha Chaham, Naoual Gamrani, Mounsif Ibnoussina, Dora Francese, Saverio Mecca
066_ The Role of Fluid Dynamics for Green Buildings Performance
067_Technological Design for Bioclimatic Architecture. Strategies and Natural Ventilation Systems for Passive Cooling in Environmental and Energy Retrofit in the Mediterranean Climate
069_ LIST OF AUTHORS