In Western countries there has been an increasing interest in adobe constructions, especially for sustainability and comfort reasons. Some billion people live in earth houses all over the world, also in seismic areas. The seismic behaviour of adobe constructions was numerically modelled through the Equivalent Frame method. The static and seismic behaviour of simple adobe buildings was studied with the code RAN and compared with that of low strength masonry buildings. Sardinia is the place in Italy where earth constructions are more widespread, with an important building tradition dating many centuries ago due to the lack of other building materials in the alluvial plain of Campidano. Earth constructions are built in Sardinia especially for comfort and sustainability reasons. For the Italian code in Sardinia, new buildings are to be checked for the seismic action, and existing buildings to be reused with important structural modifications and changes of the loading conditions.
Earthen constructions are often built in seismic areas, notwithstanding their vulnerability to even low-intensity earthquakes. Numerical simulations and design methods to predict the seismic response of earthen constructions under future earthquakes and, if any, to design and implement retrofitting systems are hence required. This study aims at evaluating the applicability of the equivalent frame method (EFM) to assess the seismic performance of adobe masonry buildings through nonlinear static analysis, allowing a trade-off between computational efficiency and accuracy in the simulation of earthquake damage. Experimental results of shaking table tests performed on a half-scale adobe building specimen were compared to the output of numerical simulations performed on the prototype building through the EFM. A satisfactory numerical-experimental agreement was found both in terms of seismic capacity features and damage to load-bearing walls. Such results indicate that the EFM can be suitably used also in adobe buildings, hence confirming previous validations on other building typologies.
In the last few years, nonregular reinforced concrete (R/C) slabs have become more popular in buildings and bridges due to architectural or functional requirements. In these cases, an optimum design method to obtain the ultimate load capacity and the minimum reinforcement amount should be used. For simple R/C slabs, the yield‐line method is extensively used in engineering practice. In addition to strength, the “true” failure mechanism is also obtained by identifying the parameters that define it and minimizing the collapse load. Unfortunately, when the mechanism is too complicated to be described or defined by several parameters (e.g., in slabs with complicated geometry), the method becomes more difficult because the system of nonlinear equations becomes harder to solve through traditional methods. In this case, an efficient and robust algorithm becomes necessary. In this paper, a structural analysis of R/C slabs is performed by using the yield‐line method in association with a zero‐th order optimization algorithm (the sequential simplex method) to avoid calculating gradients as well as any derivatives. The constraints that often limit these parameters are taken into account through the exterior penalty function method, leading to a successful solution of the problem. Considering that the direction of each yield‐line is sought by minimizing the ultimate load and finding the parameters defining the collapse mechanism, another parameter concerned with the direction of an orthotropic reinforcement grid is introduced. In this way, the number of unknown parameters increases, but aside from obtaining the ultimate load and the parameters defining the collapse mechanism, the solution also finds both best and worst reinforcement orientations.
<p>Hakka Tulous are massive circular earth constructions of the Fujian Province, China, included in the UNESCO World Heritage list. They are subjected to earthquakes of medium magnitude, but their response to the seismic action is not yet investigated in depth. The seismic response of Fujian Tulous was herein investigated through pushover analysis modelling the Tulou structure by finite elements. Although the Tulou is a big construction with a circular earth wall of about fifty meters in diameter, a micromechanical approach was used to model the earth nonlinear behaviour. Even if no binder is added to the earthen material, the Concrete Damaged Plasticity model can be adopted and has shown to be effective in modelling its nonlinear behaviour, as well as the nonlinear response of the Tulou earth wall. Performing pushover analysis of a big earth structure using a micromechanical approach seems to give reliable results, that must be proved by future research.</p>
The aim of this study is to examine if urban pollution can modify indices of genotoxic damage.Research of articles inherent in the evaluation of these alterations. Differents categories of exposed workers are included in the study (cases, in number of 7287) and compaired with no exposed workers (controls, in number of 8054). To calculate the result of meta-analysis the Effect Size (ES) was used and the confidence interval was calculated.In this category we evaluated 54 studies and we observed significantly differences in the complex.Starting from the individual variables analysis investigated, between exposed and not exposed group, we underline the utility to deepen the studies concerning of these parameters, to appreciate their benefits and to safeguard health of exposed workers.
The overall seismic response of Hakka Tulous, massive traditional earth constructions located in the Fujian Province (China) and part of the UNESCO list of World Heritage buildings, is investigated. For this aim, non-linear static analysis (pushover) was used. Since Tulous are complex circular earth structures (about 50 m in diameter) stiffened by wooden frames along the whole inner perimeter of the circular earth wall, non-linear finite element models are hard to implement because convergence is difficult to achieve and very long computation time would be required given the large number of elements and degrees of freedom. For the above reasons, the equivalent frame approach is often used for masonry structures. Even if a few approximations are needed, non-linear static analysis of even very complex masonry structures can be successfully performed with fewer convergence problems and lower computational efforts. The seismic analysis of a representative circular Tulou is carried out. An extension to circular masonry structures of the analysis by macroelements through the equivalent frame method is hence studied. The results provides insight on the Tulou's failure modes and on its overall seismic response. Since this is the first study on the overall seismic response of these complex earth constructions, further research is needed to deepen our knowledge of their structural behaviour.
The present study aims to analyzing the relation between the work-related distress with the exposition to ionizing radiations in the radiology technicians, in the hospital environment.Our present study has been conducted on a group of 36 sanitary technicians (14 women and 22 man, with an average age of 48±10,1 years) working in the Hospital Radiology Pavilion; 28 of them were less-exposed to radio-active emissions (B Category) and 8 were more exposed to radio-active emissions (A Category). The HSE questionnaire has been administered to all the 36 sanitary technicians. The data analysis and statistical elaboration were conducted using the HSE Tools. After that, the non-parametric Mann-Whitney test was applied to the comparison of the medians of two independent samples.The HSE tools questionnaire's analysis (made on the whole population) made evident some criticalities in the domains of the managerial support and of the professionals' relationships: in the B Category group (less- exposed to radio-emissions) further criticalities emerged, in the domain of peer-support and in the change domain. The HSE questionnaire analysis, made adopting the Mann-Whitney non-parametric statistical test, significant statistical differences emerged from 2 questions of the 35 sub-administered questions, regarding the mostly radio-exposed workers.From the research analysis, the authors deducted the small relevance of the emerged criticalities for the two groups of workers; the researchers also believe that, given the (almost complete) homogeneity of the results emerging from the statistical analysis (done with the Mann Whitney test), the perception of the of the work-related distress risk is irrelevant to the dose of ionizing radio-exposition.
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