Efficiency and Cost-Benefit Analysis of Seismic Strengthening Techniques for Old Residential Buildings in Lisbon

This paper presents a study on the techno-economic efficiency of seismic strengthening techniques for old residential buildings, with application to construction typologies in Lisbon (stone masonry and “Placa” buildings). A comprehensive review on strengthening techniques and implications for the seismic behavior is made. Different strengthening schemes are implicitly simulated within equivalent frame models of the representative buildings. Then, pushover analysis is applied in order to compare the seismic performance of the buildings, before and after strengthening. A cost-benefit analysis of the strengthening solutions is finally performed, comparing the economic benefit gained by reducing the seismic damage, against the intervention cost.     

Floor Spectra of Inelastic RC Frame Buildings Considering Ground Motion Characteristics

A range of reinforced concrete frame buildings with different levels of inelasticity as well as periods of vibration is analyzed to study the floor response. The derived floor acceleration response spectra are normalized by peak ground acceleration, peak floor acceleration, and ground response spectrum. The normalization with respect to ground response spectrum leads to the lowest coefficients of variation. Based on this observation as well as previous studies, an amplification function is proposed that can be used to develop design floor spectra from the ground motion spectrum, considering the building’s dynamic characteristics and level of inelasticity.     

Rocking of Non-symmetric Rigid Blocks in Buildings Considering Effects Associated with Dynamic Soil-Structure Interaction

A dynamic model for the estimation of the rocking and/or overturning response of a free-standing non-symmetric rigid block considering rotational and horizontal excitation is proposed. The block is situated at different levels of a building with flexible base subjected to earthquakes. Base flexibility introduces the rotational component of the excitation due to dynamic soil-structure interaction (DSSI). The model is used to assess the influence of the dynamic soil-structure interaction on the behavior of the block. An illustrative example of the proposed model for non-symmetric rigid blocks in 5-, 10-, and 15-story buildings located in soft soils considering earthquakes from different seismic sources is presented. Results show that it is important to consider kinematic effects as well as inertial effects of DSSI in the dynamic response of contents. The influence of base flexibility depends on the change of spectral intensities associated to the increase of the building structural period and is larger for higher building levels.     

Investigation Techniques for the Seismic Response Assessment of Buildings Located in Historical Centers

ABSTRACT

It is an acknowledged fact that historical centers, given its significance from the cultural and architectural viewpoint, bring further challenges in terms of maintenance planning, survey, and safety assessment. The preparation of an adequate investigation plan and the extent of data to be collected is highly reliant on many aspects, such as the category of the architectonic asset, the importance of the heritage site, or the resources available, for example. In what regards the seismic response assessment of urban cultural heritage assets located in historical centers, the amount and detail of data also depend on this article, scale of assessment, and current state of conservation and occupation. Within this framework, this article provides an overview of the state of the art of investigation techniques currently used in survey operations, which are currently available for improving the knowledge level of urban cultural heritage assets within historical centers, as a supporting tool for the seismic response assessment of such singular assets. Finally, acknowledging the lack of accuracy when evaluating the seismic response of an asset enclosed in aggregate as an isolated structure, this article also focuses on the identification of the main particularities inherent to buildings enclosed in aggregate.     

History in Two Dimensions or Three? Working Class Responses to History

Research carried out by the author in North Carolina (2007) aimed to assess how museums might help rebuild identity in communities devastated by economic decline. Interviews, compared with examples from ‘Time and Tide’, Yarmouth, UK, suggested that working class people feel a strong need for history, intense emotional ties to the industrial landscape, and believe that museums can radically change their lives. The evidence suggested that the importance of history to people’s sense of self has been underestimated, particularly in the case of the industrial poor. This paper considers reasons for this underestimation, and suggests that these groups may also have higher and more wide‐ranging expectations of history than intellectuals do. It suggests these ‘emotional’ uses of history, rather than being inferior to academic history, may be richer, and that this ‘three‐dimensional’ experience of history exhibited by the urban poor can enrich the two‐dimensional historical experience of the researcher or museums professional.     

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.     

On the Design of Viscous Dampers for the Rehabilitation of Plan-Asymmetric Buildings

In this article, one of the procedures proposed in literature for the design of viscous dampers to be inserted in existing buildings is examined and extended to 3D eccentric buildings. The proposed procedure has been verified through a case study characterized by a six-story RC building. Both plan-symmetric and plan-asymmetric configurations have been considered for comparisons. The effect of considering the plan-asymmetry in the design has been studied. Moreover, also the importance of considering the higher modes has been investigated. The effectiveness of the design procedure has been then evaluated through the comparison with nonlinear dynamic analyses.     

Applying new approaches to modeling diet and status: isotopic evidence for commoner resiliency and elite variability in the Classic Maya lowlands

Classic Maya states were characterized by a high degree of socioeconomic stratification. This paper investigates the degree to which status, as defined by grave goods and tomb construction, influenced dietary patterns of elites and commoners throughout the Classic Period (200–900/1000 AD) of the southern lowlands. We compile a database (N = 102) of previously-published stable isotope ratios (δ¹³C collagen, δ¹³C apatite, and δ¹⁵N collagen) from Maya bone mineral and collagen, and interrogate these data through two new isotopic modeling techniques: a simple carbon isotope model ( Kellner and Schoeninger, 2007; Froehle et al., 2010) and a multivariate isotope model ( Froehle et al., 2012). We find that Maya elite diet varied significantly through time in terms of maize consumption and trophic level, while commoner diet remained remarkably stable. These findings provide new information relevant to studies of ancient Maya class structure and to studies of subsistence strategies of the pre-Columbian Americas.     

Design Principles for Minimum Torsional Response of Wall-Frame Concrete Structures

A seismic design procedure is described incorporating the well-accepted property that the stiffness of reinforced concrete elements is strength dependent and the requirement that the method of assigning strength to elements should be aiming at minimum torsional phenomena. Such a response allows a direct comparison with the findings of a static nonlinear analysis, which may provide the limits of story drifts and the induced plastic rotations in potential plastic hinges. The requirement of a practically translational response implies that the element strength assignment should be based on planar considerations and the initially elastic response should be of minimum torsion.     

Analysing Heritage Landscapes with Historical GIS: Contributions from problem-based inquiry and constructivist pedagogy

This article examines a practical classroom experience using GIS technologies to analyse aspects of a local heritage landscape. An inventory of historic buildings comprising architectural and construction details was revised in the field and then analysed using GIS software. Elements of the geographies of these buildings were displayed using thematic mapping and students used these maps to develop explanatory hypotheses and to suggest policy options for future management of the heritage landscape. Practically, the project demonstrated the contribution GIS can make to historical geography methods, engaged students in an externally supported research partnership working with real-world data, and suggested directions for local public policy formation. Pedagogically, the project demonstrated that historical GIS can be used effectively to shape problem-based inquiry and constructivist learning.