Capacity Design of Coupled RC Walls

Capacity design aims to ensure controlled ductile response of structures when subjected to earthquakes. This article investigates the performance of existing capacity design equations for reinforced concrete coupled walls and then proposes a new simplified capacity design method based on state-of-the-art knowledge. The new method is verified through a case study in which a set of 15 coupled walls are subject to nonlinear time-history analyses. The article includes examination of the maximum shear force in individual walls in relation to the total maximum shear force in the coupled wall system, and subsequently provides recommendations for design.     

Numerical Study on the Peak Strength of Masonry Spandrels with Arches

This article presents a numerical study on the force-deformation behavior of masonry spandrels supported on arches which are analyzed using simplified micro models. The model is validated against results from quasi-static cyclic tests on masonry spandrels. A large range of spandrels with different arch geometries, material properties, and axial load ratios are studied. The numerical results are compared to peak strength values predicted with an existing mechanical model. Finally, estimates for the initial stiffness and the spandrel rotation associated with the onset of strength degradation are derived.     

Governing Social Cohesion in Shrinking Cities: The Cases of Ostrava,Genoa and Leipzig

Social cohesion always appears more frequently as a policy goal of the European strategy that promotes the integration of spatial, economic, and social dimensions of growth. This comprehensive approach also has to deal with the social consequences of demographic change, tackle urban poverty, and guarantee access to amenities in isolated neighbourhoods. Such objectives represent specific challenges for shrinking cities, where processes of population decline, job losses and economic constraints as well as financial restrictions create a much more complicated starting position and might make the achievement of the social cohesion even more difficult than in non-shrinking cities. Set against this background, this paper analyses the efforts of three shrinking cities (Ostrava, Genoa, Leipzig) to promote social cohesion under the condition of urban shrinkage, and examines which policies are being promoted to solve problems such as ethnic segregation, ageing, and socio-spatial inequalities. The results show that even though shrinkage does lead to increased challenges for social cohesion, the attempts of policies to tackle them still appear to be secondary priorities, sectoral rather than comprehensive, and involve a certain delay.     

High-skilled Return Migration and Knowledge-based Development in Poland

It is by now well known that return migration of the highly skilled can have a significant impact on knowledge-based development in the regions to which they return. Whereas previous research has mainly focused on developing and newly industrializing countries, this paper looks at high-skilled return migration in an East European transformation economy, namely Poland. In our paper, we propose an analytical framework which integrates migration theory and regional development perspectives. Based on narrative interviews with high-skilled return migrants in Warsaw and Poznań, we show that high-skilled return migrants have an impact on economic development by acting as both investors and innovators, i.e. that they transfer and successfully integrate financial means as well as different types of knowledge into these local economies. Furthermore, the Polish example illustrates that social relations and institutional context are crucial in understanding how high-skilled return migrants contribute to knowledge-based development.     

Methods and Approaches for Blind Test Predictions of Out-of-Plane Behavior of Masonry Walls: A Numerical Comparative Study

ABSTRACT

Earthquakes cause severe damage to masonry structures due to inertial forces acting in the normal direction to the plane of the walls. The out-of-plane behavior of masonry walls is complex and depends on several parameters, such as material and geometric properties of walls, connections between structural elements, the characteristics of the input motions, among others. Different analytical methods and advanced numerical modeling are usually used for evaluating the out-of-plane behavior of masonry structures. Furthermore, different types of structural analysis can be adopted for this complex behavior, such as limit analysis, pushover, or nonlinear dynamic analysis.

Aiming to evaluate the capabilities of different approaches to similar problems, blind predictions were made using different approaches. For this purpose, two idealized structures were tested on a shaking table and several experts on masonry structures were invited to present blind predictions on the response of the structures, aiming at evaluating the available tools for the out-of-plane assessment of masonry structures. This article presents the results of the blind test predictions and the comparison with the experimental results, namely in terms of formed collapsed mechanisms and control outputs (PGA or maximum displacements), taking into account the selected tools to perform the analysis.