A Novel Procedure for Simplified Nonlinear Numerical Modeling of Structural Units in Masonry Aggregates

ABSTRACT

Historical centers are always composed of masonry building aggregates often designed without respecting seismic design criteria. The current seismic Italian code does not foresee a clear calculation method to predict their static nonlinear behavior. For this reason, in this article the seismic response of structural units into masonry aggregates has been predicted through a simplified modeling approach. The implemented procedure has been calibrated on the results of a numerical model performed by using the Equivalent Frame Method (EFM), implemented within a Finite Element Method (FEM) calculation program, used to investigate a basic building compound representative of the constructive techniques developed in the past decades in the Southern Italy.

First, the whole aggregate has been modeled and analyzed in the nonlinear static field in order to evaluate the seismic behavior of both intermediate and head structural units.

Later on, the seismic response of these structural units, considered as isolated structures, has been assessed by considering in simplified way their position in the aggregate, as well as the influence of other constructions.

Finally, the achieved results on the above single analysis cases have been compared with those deriving from the investigation of the whole building compound, allowing to confirm the effectiveness of the proposed novel analysis procedure.     

Seismic behavior of two Portuguese adobe buildings: Part I - in-plane cyclic testing of a full-scale adobe wall

This article addresses the laboratory testing of a full-scale double-T shaped adobe wall, under in-plane horizontal cyclic loading of increasing amplitude, with the aim of contributing to the understanding of the seismic behavior of adobe structures. The wall was built with lime adobes taken from an existing building and mortar with a traditional composition. The behavior of the wall was assessed in terms of: shear stress versus horizontal drift and moment versus rotation relationships; maximum lateral strength; drift and rotation at peak stress; evolution of stiffness, lateral displacements, dissipated energy, and natural frequency; and damage pattern. The wall exhibited brittle behavior and in-plane strength corresponding to 56% of the vertical load. Cracking was observed with an X-shaped pattern whereas no sliding occurred at its base. This research supported the subsequent development of a repair and retrofit solution and also of numerical models to simulate the seismic behavior of two adobe buildings.     

Statistical Characterization of Structural Demand under Earthquake Loading. Part 1: Robust Estimation of the Central Value of the Data

This article is the first of two companion articles addressing the statistical characterization of seismic demand. Performance-based earthquake engineering methodologies often require the characterization of central value estimates of structural demand. Since outliers can occur in the data, central value estimates should be determined by robust estimation methods. The performance of 50 robust central value estimators is evaluated, for different sample sizes, using the chord rotation, curvature, shear force, and inter-story drift demands obtained after analyzing five reinforced concrete structures under real earthquake records scaled to several intensities. Based on the results, seven estimators are proposed for different sample sizes.     

Genealogies of Destruction: An Archaeology of the Contemporary Past in the Amazon Forest

In this article we look at the destruction of the Amazon forest through an archaeological lens. We describe the devastation brought about by illegal loggers and ranchers to the last remaining old-growth forests of Maranhão (NE Brazil), where the Awá hunter-gatherers live. We argue that archaeology can provide an alternative and more critical look at global consumerism by manifesting the crude materiality and abject violence that lurks behind the goods consumed in the West. We followed the tracks of a group of loggers deep inside the forest and report what we saw.     

Early Evidence for Pig and Dog Husbandry from the Neolithic Site of An Son,Southern Vietnam

An Son in southern Vietnam is one of a series of Neolithic (food producing) settlement/cemetery sites in Southeast Asia that appear, archaeologically, shortly before and after 2000 cal. bc . Excavations in 2009 produced a small but important assemblage of vertebrate remains that permit relative comparisons with other zooarchaeological assemblages of similar date in Thailand and northern Vietnam. At An Son, domestic dogs are present from the earliest known phases of occupation with butchery evidence and a high proportion of canid remains, suggesting they were possibly used as a food resource. Suid bones were recovered from the earliest phases of the site excavated, and pig husbandry can be identified from at least 1800 to 1600 cal. bc . There is also evidence for the use of a range of other resources including fishing, hunting and the capturing of turtles. Copyright © 2012 John Wiley & Sons, Ltd.     

Historical Archaeology of Lavras do Abade: An Environmental Conflict in Nineteenth-Century Brazil

The Lavras do Abade research is a historical archaeological study about a gold mining village in midwestern Brazil that was destroyed by an environmental conflict at the end of the nineteenth century. This article concerns the history and archaeology of Lavras do Abade and consists of a post-disciplinary intersection of documentary and material sources about the site. In addition, only this type of reconstruction of a long-term event permits the scientific analysis of all the possible causes and consequences of this ecological contention. In this way, historical archaeology can be used to transpose a simple narrow view of the reconstruction of the past and offer insights into understanding similar unrest and group conflict today and in the future.     

Focusing on Chinese nationalism: an inherently flawed perspective? A reply to Allen Carlson

My article replies to Allen Carlson's critique of the existing literature on Chinese nationalism (Carlson's article was published in Volume 15, issue 1 of Nations and Nationalism, 2009). I address Carlson's criticisms and proceed to evaluate his proposal to move away from an allegedly unhelpful focus on nationalism towards the allegedly more illuminating framework of national identity construction. My approach to the existing literature on Chinese nationalism acknowledges efforts made within it at grappling with issues of theory and definition and builds on this acknowledgement to operate a selective appraisal of its strengths and weaknesses. I argue that while some of the problems identified by Carlson do indeed plague the literature, his advocacy of abandoning nationalism as a focus of research is unwarranted. There is continuing validity in using nationalism as a lens for understanding how China sees its place in the world.     

Roman amber identified as Siegburgite

A small amber fragment from the period of Roman occupation of Numantia (Garray, Spain) was characterised by Fourier transformed infrared spectroscopy and optical microscopy. The material was found to be a polystyrene-like material, which is a very rare fossil resin known as Siegburgite or class III amber. Until now, this material was found in Europe only at two sites, both localised in Germany, and it is the first time that this type of amber was identified in wrought archaeological artefacts. The discussion includes the applicability of the method to distinguish false from true and amber of different origins, its use and trading as well as a hypothesis for a transport route. The study highlights the need for a more systematic study of archaeological amber remains. The finding also proves the exploitation and trading of local, non-Baltic amber deposits throughout the Roman Empire.     

The Terramare and the surrounding hydraulic structures: a geophysical survey of the Santa Rosa site at Poviglio (Bronze Age,northern Italy)

The Terramara Santa Rosa is a Middle and Late Bronze Age archaeological site located in the Po alluvial plain, northern Italy. It is constituted of two moated villages delimited by earthen ramparts. The peripheral structures of the site are sealed by fine-textured flood plain deposits and they have not been fully explored through excavation due to their large extent. Because the shape of the villages and their relation to moats and the fluvial network are of paramount importance to understanding the landscape management and the use of water resources in the Terramare civilisation, a geophysical survey was planned to extend the results of the existing archaeological excavations to the site scale. A frequency-domain electro-magnetic sounding (FDEM) and electrical resistivity imaging (ERI) covered an area of approximately 26 ha; ERI was conducted for a total length >9000 m. Despite the predominance of electrically conductive fine-textured sediments, electrical resistivity anomalies were observed and they were attributed to subtle lithological differences in the sedimentary context of the alluvial plain. The geophysical interpretation, after the calibration with the excavation data, revealed the structures of the Terramara and of the surrounding hydraulic network, which are not visible at the surface due to flood plain deposits. The Santa Rosa site was founded in a favourable geomorphological position, on the top of a crevasse splay lobe of the adjoining Po palaeo-channel, rising above the surrounding alluvial plain. The Terramara and their surroundings were delineated through an artificial modification of this pre-existing crevasse splay lobe and a well-targeted urban design, with the objective of diverting water, most likely from a palaeo-channel of the Po River, through the digging of peripheral moats used to collect water around the site and to distribute it to the surrounding fields for irrigation. The water management documented by this study in the Terramara Santa Rosa can be considered as paradigmatic for the whole Terramare civilisation, which is therefore responsible of the introduction of the irrigated agriculture into western Europe for the first time.