Improved procedure for determining the ductility of buildings under seismic loads

Displacement ductility is a parameter that characterizes the seismic response of structures. Moreover, displacement ductility can be used in order to determine whether a structural design, performed according to a specific seismic code or not, may achieve the main goal of the seismic design: to develop energy dissipation in a stable manner. Determination of displacement ductility is not an easy task, because the structural response usually does not show a clear location of the points that define yield and ultimate displacements. In this paper, some of the main procedures for ductility displacement are revised and compared, and then improvements are performed to such procedures in order to compute the displacement ductility. A new procedure is then introduced, leading to determine the ultimate displacement using the seismic collapse threshold and the yield displacement, achieving the balance of dissipated energy. The procedure has been used to calculate displacement ductility of reinforced concrete framed buildings.Peer Reviewe

Evaluación de la vulnerabilidad sísmica de estructuras de acero residenciales del Ecuador

Nowadays, there are a large number works focused on determining the seismic vulnerability of structures. This feature is not accidental, but rather the product of concern to the scientific, professional and organizations responsible for risk management community to reduce the destructive effects caused by earthquakes in the infrastructure and society. Globally destructive events that have occurred during the previous and present decades have contributed to this initiative; among them, the Sichuan, China (2008), Port au Prince, Haiti (2010), Maule, Chile (2010) or Tohoku, Japan (2011) earthquakes can be mentioned, which had as consequences many dead, injured and homeless people. It is well known that an earthquake can cause humanitarian disasters not only by the number of casualties and injured people but also for the destruction of cities where thousands of families live and work. All the above mentioned reasons reveal the need of revision and improvement of the seismic design codes, construction practices and policies that allow buildings to have a better performance against the strong ground motions. This is the context in which this work was developed. It contains results of a research entitledPostprint (published version

Too Big to Manage: US Megabanks’ Competition by Innovation and the Microfoundations of Financialization

Disagreements over the systemic implications—the future—of financialization can be traced in part to the absence of sustained attention to the role of banking firms in driving this secular shift forward. That is, the financialization literature lacks an adequate microfoundation. Accounting for the drivers of financialization processes solely at the macro level overlooks the problems of how these processes came about and whether they are sustainable. This paper addresses this explanatory gap, arguing that a key independent microeconomic driver of increasing financialization did exist: the incessant efforts by money-centre banks in the USA to break out of Depression-era restrictions on their size, activities, and markets. These banks’ growth strategies in turbulent times led to an institutional (meso) shift—the rise of a megabank-centred shadow banking system—that now shapes global financial architecture even while operating in ways that are unsustainable. In short, too-big-to-manage megabanks are at the heart of the fragility and instability of the economy today

Effect of peracetic acid on geosmin and 2-methylisoborneol levels in recirculating aquaculture system raising rainbow trout Oncorhynchus mykiss

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Shell model of BaTiO₃ derived from ab-initio total energy calculations

A shell model for ferroelectric perovskites fitted to results of first-principles density functional theory (DFT) calculations is strongly affected by approximations made in the exchange-correlation functional within DFT, and in general not as accurate as a shell model derived from experimental data. We have developed an isotropic shell model for BaTiO₃ based on the PBEsol exchange-correlation functional [Perdew et al., Phys. Rev. Lett. 100, 136406 (2008)], which was specifically designed for crystal properties of solids. Our shell model for BaTiO₃ agrees with ground state DFT properties and the experimental lattice constants at finite temperatures. The sequence of phases of BaTiO₃ (rhombohedral, orthorhombic, tetragonal, cubic) is correctly reproduced but the temperature scale of the phase transitions is compressed. The temperature scale can be improved by scaling of the ab-initio energy surface.Article Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This is the publisher’s final pdf. The published article can be found at: http://scitation.aip.org/content/aip/journal/jap

Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists

This research defines diagnosis criteria in R/C one-way slabs with severe corrosion at the lower prestressed reinforcement of the joists and proposes specific actuation criteria and constructive recommendations to increase the safety. The corrosion of this reinforcement is the most common damage in building structures, and the use of aluminous cement in the precast joists can aggravate the corrosion. The usual cases of entire residential buildings with different degrees of damage and with a few or all joists affected in a slab have been simulated. ACI-318 is used as an acceptance criterion for existing structures in the simulations, and a ratio between the ultimate load and the service load is defined as valuation coefficient. By this way, the residual safety for a damaged structure is known. Results are in accordance with the extensive experience in real intervention cases, which often still have high safety reserves.Vercher Sanchis, JM.; Gil Benso, E.; Mas Tomas, MDLA.; Lerma Elvira, C. (2013). Diagnosis / Intervention criteria in damaged slabs by severe corrosion of prestressed joists. Journal of Performance of Constructed Facilities. (04014040). doi:10.1061/(ASCE)CF.1943-5509.0000515S0401404