Experimental characterization of the constitutive materials composing an old masonry vaulted tunnel of the Paris subway system

A significant proportion of the Paris metro tunnels comprise a masonry vault built out of stone blocks and mortar joints, and sidewalls and slabs made of unreinforced concrete. In order to provide the necessary data for future structural evaluation, an extensive laboratory testing programme has been conducted to characterize the materials of the tunnel separately, i.e., mortar, stone, and concrete. The tests, carried out on specimens taken from cores extracted from a 1930s tunnel, enabled to determine the mechanical properties, including direct tensile, shear strength, and mode I fracture energy, as well as the properties of the stone-mortar interface. Results show that the masonry mortar joints could reach 10 cm in width, and that blocks of stone varied in composition and porosity, thus producing a wide range of mechanical properties. The concrete was composed of large-sized aggregates and showed low stiffness and strength. Based on these experimental results, ratios between mechanical characteristics are hereby proposed. Perspectives on the use of this experimental data in a finite element model are then discussed.     

History and Characteristics of Construction Techniques Used in Traditional Timber Ottoman Houses

The aim of this article is to make a comprehensive review of the traditional timber house constructions in Turkey, which constitutes the majority of the existing Ottoman architectural legacy. After a short historical background focused on the Ottoman territory, the first section explores regional differences in the housing tradition, developed according to local features and defined by architectural features, material characteristics, and availability of materials. Derived from these regional differences, in the second section diversity in traditional timber construction systems in Turkey is described with special emphasis on the Ottoman h?m?? system. In this part, besides the discussion of the h?m?? technique which spread over Ottoman lands from the Balkans to Syria, the timber masonry and frame systems of the Eastern Black Sea Region and Thrace are presented in detail with visual support.     

The regional impact of the channel tunnel: Qualitative and quantitative analysis

The paper addresses the question of how different types of regions mill be affected by the development of a major new transport infrastructure such as the Channel Tunnel. It summarizes a study on the regional impacts of the Channel Tunnel throughout the European Union (EU). The research design combined qualitative methods of futures exploration employing 13 regional case studies with quantitative forecasting techniques using the MEPLAN transport and economic model. The paper presents the methodology and major results of the two approaches with respect to the impacts of the Channel Tunnel on transport flows and regional development in Europe and draws conclusions for transport and regional policy of the EU. The paper demonstrates that the removal of a bottleneck like the Channel Tunnel does not necessarily induce economic gains in all adjacent regions. Much more important for regional economic development than the reduction of transport costs are the image to be a region well integrated into the European high‐speed transport network and an active political response of the region to take advantage of opportunities like the Channel Tunnel.     

Palaeolithic chert exploitation in the limestone stretch of the Egyptian Nile Valley

Different raw material procurement strategies are attested in the limestone stretch of the Egyptian Nile Valley. Chert cobbles from Nile terraces or from their derived deposits were generally used. Four main procurement strategies have been recognized. During the Middle Palaeolithic intensive surface collecting was the most common strategy. However, open quarrying techniques involving features such as ditches are also attested. True subterranean mining with vertical shafts and underground galleries was known by the Early Upper Palaeolithic at 35,000 years BP. Extracted nodules were processed at the procurement sites. The study of the reduction strategies has proved valuable in gaining a better understanding of the Palaeolithic sequence of the Egyptian Nile Valley.

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Résumé Différentes stratégies d'obtention de matière première ont été reconnues dans la zone calcaire de la vallée du Nil égyptien. En majorité, ce sont des galets de chert qui ont été utilisés. Les stratégies d'obtention se classent en quatre types. Au Paléolithique Moyen la méthode la plus fréquente était la collection intensive en surface. Mais il y eut aussi une technique d'exploitation en profondeur, à l'aide de tranchées à ciel ouvert. Une véritable extraction minière avec des puits verticaux et des galleries souterraines fut pratiquée dès le début du Paléolithique Supérieur, vers 35.000 BP. Les galets extraits étaient réduits sur les sites d'exploitation mêmes. L'étude des processus de réduction nous a permis de mieux comprendre la séquence paléolithique de la vallée du Nil égyptien.