Characterization of concrete from Roman buildings for public spectacles in <Emphasis Type="Italic">Emerita Augusta</Emphasis> (Mérida,Spain)

The aim of this work is to characterize the original concrete from Roman buildings for public spectacles, theatre and amphitheatre, from Emerita Augusta, Mérida, Spain. An advanced knowledge of the Roman concrete composition is required for a reliable restoration and preservation of these ancient monuments. The concrete was studied through mineralogical (optical polarized microscopy and X-ray diffraction) and petrophysical (bulk and real density, open porosity to water and Hg, mechanical strength and ultrasonic velocity) analyses. With this work, it is possible to fill the gap that exists in this field and the characterization of the materials used in the Roman concrete from these two buildings, never previously studied, despite the significance of this archaeological ensemble, declared a World Heritage Site by UNESCO in 1993. The results allowed us to determine the composition of the Roman concrete and to infer the provenance of the aggregates used in these monuments.     

Updating Numerical Models of Masonry Arch Bridges by Operational Modal Analysis

This article aims at presenting and discussing the strategies for updating the finite element numerical modeling of stone masonry arch bridges using operational modal analysis. The study comprehended three bridges: two old ones, the St. Lázaro and the Lagoncinha bridges, and a recently constructed bridge in Vila Fria, Portugal. Updating of the bridge models is performed by comparing the numerical and experimental modal parameters. Three-dimensional detailed numerical models are used to perform modal analysis of the bridges. Experimental modal identification of the bridges is based on the measurement of their acceleration responses during normal operation. The assigned material properties are also based on available results obtained from in situ and laboratory tests and on the results of visual inspection and historical research carried out for both old bridges.     

Planning Cultures and Histories: Influences on the Evolution of Planning Systems and Spatial Development Patterns

Abstract

This special issue addresses the influences of planning cultures and histories on the evolution of planning systems and spatial development. As well as providing an international comparative perspective on these issues, the collection of articles also engages in a search for new conceptual frameworks and alternative points of view to better understand and explain these differences. The articles focus on three main aspects: the change in planning systems and its impact on spatial development patterns; the interrelationship between planning cultures and histories from a path-dependency perspective; and the variations in physical development patterns resulting from different planning cultures and histories. Papers from different parts of the European continent present evidence at different scales to illustrate these aspects. In all cases, the specific combinations of political, ideological, social, economic and technological factors are important in determining urban and regional planning trajectories as well as spatial development patterns.