Ductility-Equivalent Viscous Damping Relationships for Beam-to-Column Partial-Strength Steel Joints

This paper seeks to contribute to the development and improvement of displacement-based design procedures, proposing improved ductility-equivalent viscous damping relationships for steel moment-resisting framed structures with dissipative beam-to-column partial-strength joints. These relationships can be used directly in procedures like the Direct Displacement-Based Seismic Design (DDBD) that uses effective stiffness, ductility-equivalent viscous damping relationships, and period-displacement relationships in a performance-based design approach. To this end, a finite element model of a steel beam-to-column sub-assemblage, characterized by an extended end-plate, is developed in ABAQUS. The model, which is validated against monotonic and cyclic experimental data obtained in previous research, is employed to carry out non-linear time-history (NLTH) analyses, using real records scaled to target several levels of ductility demand. A procedure is then proposed and applied to determine the ductility-equivalent viscous damping relationships of the sub-assemblages. The equivalent linearization technique is applied to the non-linear responses obtained in the NLTH analyses, using an elastic single degree of freedom structure and the elastic displacement spectra. The influence of joints mechanisms and of the dynamic characteristics of the structure in the equivalent viscous damping is investigated, and an expression for ductility-equivalent viscous damping is proposed. The proposed expression represents a clear improvement in relation to the existing expressions available in literature.     

Simplified Macro-Model for Infill Masonry Panels

In structural analyses, masonry infill walls are commonly considered to be non structural elements. However, the response of reinforced concrete buildings to earthquake loads can be substantially affected by the influence of infill walls. In this article, an improved numerical model for the simulation of the behavior of masonry infill walls subjected to earthquake loads is proposed and analyzed. First, the proposed model is presented. This is an upgrading of the equivalent bi-diagonal compression strut model, commonly used for the nonlinear behavior of infill masonry panels subjected to cyclic loads. Second, the main results of the calibration analyses obtained with two series of experimental tests are presented and discussed: one on a single frame with one story and one bay tested at the LNEC Laboratory; and the second, on a full-scale four story and three-bay frame tested at the ELSA laboratory.     

Effect of organic and inorganic consolidation agents on Tlaltecuhtli monolith

A huge monolithic piece corresponding to the first years of the sixteenth century has been discovered in Mexico City. It represents the earth goddess Tlaltecuhtli. The preservation of such a magnificent piece is imperative. Therefore, the surface has to be characterized and the interaction of consolidants with the rock has to be understood.Some of the consolidation methods are impregnation of the mineral with nopal or silicic acid derivatives. In this work we compare the physico-chemical effects of organic and inorganic consolidants. Original and impregnated samples are characterized with a series of original techniques: X-ray diffraction, nuclear magnetic resonance, nitrogen adsorption and small angle X-ray scattering. Fractal dimension, specific surface area and pore size distribution clearly differentiated the samples. The organic materials, nopal gum or slobber, cover the mineral particles with a smooth layer. The KSE solutions react and lead to microporosity.     

Importing and exporting spatial needs: A Dutch approach1

The increasing demand for space determines much of the approach to spatial planning in countries with a high population density like the Netherlands. In the next three decades more land will be needed for housing, work, traffic, leisure, nature and water. There is only one sector that will yield land: agriculture. The Dutch Minister of Spatial Planning has presented six intervention strategies to cope with the increasing demand for space: (1) priority setting; (2) export spatial needs; (3) reduce the need for space in accordance with policy; (4) intensify land use; (5) combine spatial needs; (6) transform spatial structures and buildings. Spatial planning in the Netherlands is becoming more and more geared to strategies 4, 5 and 6, which take the need for land as given. This paper seeks to explain that the first three strategies, and strategy 2 in particular, are also crucial for a country like the Netherlands, even though the policies associated with them would not generally be labelled spatial. For the spatial planner, however, the export of spatial needs is relevant as this determines the outcome of spatial planning to a large extent. This shall be illustrated by reporting on international residential migration, the use of leisure homes and second homes, international business migration and the restructuring of the agricultural sector. The Netherlands is not only exporting spatial needs, but also in the same time even imports needs at a larger scale, which puts spatial planning on a larger pressure. In the past the lack of space was solved by relinquishing land that was originally earmarked for water or nature. But the need for space for water and nature has increased recently and will continue to do so in the coming decades. This makes intervention strategy 2 even more relevant for the future. Spatial planners need to widen their horizons and include the import and export of spatial needs in their analyses.     

Change within the change: pregnancy,liminality and adventure tourism in Mexico

Abstract

Despite the growing number of pregnant women engaging in outdoor adventure activities, very few studies have explored pregnancy or the specific needs and challenges of pregnant women in tourism research. To fill this gap in the literature, we examine the participation of pregnant women in adventure tourism through the theoretical lens of liminality. Conceptualising pregnancy as a liminal stage in which women are ‘suspended’ between two statuses, opens diverse possibilities to delve into women’s experiences of embodiment, bodily image and control. In this sense, pregnancy is understood as an ‘internal change’, which adds specific challenges to women’s practice of adventure tourism, including bodily changes and different perceptions of risk-taking. Similarly, the context of adventure tourism provides an ideal space to reflect on liminal transitions and the ‘outside changes’ that pregnant women go through in the predominantly masculinised spaces that characterise this tourism segment. Semi-structured interviews were conducted with 35 Mexican women who actively pursue adventure tourism and who had engaged in these activities during at least one pregnancy. The analysis indicates the importance of norms and social expectations experienced by pregnant women when doing adventure tourism. The concept of the ‘rhizomatic body’ proved to be a valuable tool when looking at the social taboos, prohibitions and rules that apply to pregnant women in specific sociocultural contexts (in this case, Mexico). By reframing and reconceptualising pregnant women and their practice of adventure activities, the social construction of pregnancy is elucidated. Finally, the study contributes to the understanding of alternative models and experiences of being a woman in gendered spaces, while shedding light on relevant behavioural patterns among pregnant tourists and the sociocultural impacts of these patterns.     

Assessing Prehispanic Herding Strategies through Stable Isotope Analysis: A Case Study from the Dry Puna of Argentina

ABSTRACT

The main goal of this work is to study the camelid herding and management strategies employed by the human groups that occupied the Dry Puna of Argentina during the late Holocene. Carbon and nitrogen stable isotope compositions were measured on bone collagen from domesticated South American camelids (llamas: Lama glama) recovered at two archaeological sites (Huirunpure and Chayal Cave). These results were interpreted using an already published data set of δ ¹³C and δ ¹⁵N values measured on bone collagen from modern herds of llamas managed in a traditional way. Our results showed that even though the archaeological sites of Huirunpure and Chayal Cave are located within different settings – at 4020 and 3700?masl respectively – and present different chronologies – 0–650 and 1300–1500 CE respectively – the llamas from both sites exhibit similar δ ¹³C and δ ¹⁵N values. This pattern was explained considering the characteristics of the vegetation communities that grow in the vicinity of both sites as well as the paleoenvironmental records of the Andean highlands. In sum, this work presents and discusses some preliminary results on the study of prehispanic herding practices in the Dry Puna of Argentina during the first 1500 years of the Common Era through stable isotope analysis.