An analytical method for the evaluation of the in-plan irregularity of non-regularly asymmetric buildings     

Melina Bosco  Edoardo M. Marino  Pier Paolo Rossi 《Bulletin of Earthquake Engineering》2013,11(5):1423-1445

This paper describes a new method for the evaluation of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ of uncoupled torsional to lateral frequencies in real multi-storey buildings. The above-mentioned parameters greatly affect the lateral-to-torsional coupling of the response of asymmetric systems and thus are of paramount importance in the assessment of the in-plan irregularity of buildings. The proposed method, which is a generalization of that suggested by Calderoni et al. (Earthq Spectra 18(2):219–231, 2002), allows the calculation of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ from the structural response to arbitrary distributions of forces and torsional couples. The effectiveness of the method is validated on some regularly and non-regularly asymmetric buildings characterised by different in-plan irregularity. The analyses demonstrate that the results of the method are rigorous in the case of regularly asymmetric systems and only slightly depend upon the heightwise distribution of the forces in the case of non-regularly asymmetric systems. Finally, the values of the static eccentricity $e_{s}$ and the ratio $\Omega _{\uptheta } $ resulting from the proposed method are compared to those obtained by means of the procedure suggested by Makarios and Anastassiadis in (Struct Des Tall Spec Build 7(1):33–55, 1998a; Struct Des Tall Spec Build 7(1):57–71, 1998b) .  相似文献   

Comparison of nonlinear static methods for the assessment of asymmetric buildings     

Melina Bosco  Aurelio Ghersi  Edoardo M. Marino  Pier Paolo Rossi 《Bulletin of Earthquake Engineering》2013,11(6):2287-2308

Traditional nonlinear static methods, e.g. the original version of the N2 method implemented in Eurocode 8, are not always effective in the assessment of asymmetric structures because of the errors committed in the evaluation of the torsional response. To overcome this shortcoming, two methods have recently been suggested by Kreslin and Fajfar (Bull Earthquake Eng 10(2):695–715, 2012) and Bosco et al. (Earthq Eng Struct Dyn 41:1751–1773, 2012). In particular, the method proposed by Kreslin and Fajfar adjusts the results of the nonlinear static analysis by means of those of a standard modal response spectrum analysis. In the method proposed by Bosco et al., the researchers suggested the use of two nonlinear static analyses characterized by lateral forces applied to different points of the deck. In this paper, the two improved nonlinear static methods and the original N2 method are applied to predict the maximum dynamic response of single- and multi-storey systems subjected to artificial and recorded accelerograms. The results highlight that the improved nonlinear static methods provide estimates which are more accurate than those of the original N2 method. Further, the comparison of the results identifies the range of the structural properties within which the original N2 method is still reliable and the range within which one of the two improved methods should be preferred.  相似文献   

Assessment of environmental hazards at abandoned mining sites: A case study in Sardinia,Italy     

Rosa Cidu  Claudia Dadea  Paolo Desogus  Luca Fanfani  Pier Paolo Manca  Giampaolo Orrù 《Applied Geochemistry》2012

In the last two centuries, several Pb–Zn mines were active in the Rio Mannu basin near Narcao (SW Sardinia, Italy), but are now abandoned. These abandoned mines pose a serious risk to the population and required an assessment of the hazard sources and the contaminant pathways in the area. The characterization plan of the Rio Mannu basin was carried out according to Italian protocols. Specifically, samples of soil, stream sediment, fine-grained ore-processing waste (from washery and flotation processes), surface water and groundwater have been analyzed in order to assess the levels of contamination in each mine area and the risks in the plains surrounding the site. Several potential chemical contaminants were considered both in solid materials and water samples. The Rosas mine was recognized as the most contaminated area in the basin, due to the presence of a large tailing pond, some fine-grained waste piles and two mine adits with concentrations of the toxic elements As, Cd, Cu, Pb, Sb and Zn exceeding Italian regulatory standards. The dispersion of contaminants occurs downstream from the small stream draining the area. In case of heavy rain the runoff into the streamlet transports the contaminated material far into the plain. The results of this study show that the characterization plan is a relatively cheap tool for establishing mitigation actions, prior to the realization of a complete, and usually expensive, remediation project at abandoned mine sites. Urgent recommended actions in the Rio Mannu basin include the treatment of the adit water prior to its discharge into the Rio Barisonis; the construction of drainage barriers on waste piles to reduce runoff and solid transport into the Rio Barisonis; the consolidation of the earthen dam containing the tailing pond of Rosas to avoid the deepening of erosion furrows that may threaten its stability.  相似文献   

A tentative description of a universal erosion profile for sandy beaches and rock beaches     

Pier Vellinga 《Coastal Engineering》1984,8(2):177-188

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Pretunnel technology: applications and design methods     

Fulvio?TononEmail author  Armando?Mammino  Daniele?Vanni  Pier?Giorgio?Borghi  Alessandro?Bertero 《Geotechnical and Geological Engineering》2005,23(5):487-518

The Pretunnel technology allows the final or preliminary lining to be built ahead of a tunnel face. The paper shows how this technology has been used for mechanizing the full-face excavation of large tunnels in difficult ground conditions with minimum settlements. Analytical methods are presented for the analysis of the lining both in deep and shallow applications. Fields of applicability are established using results of parametric studies based on the methods proposed.  相似文献   

Structure and evolution of the Bay of Pozzuoli (Italy) using marine seismic reflection data: implications for collapse of the Campi Flegrei caldera     

Pier Paolo Bruno 《Bulletin of Volcanology》2004,66(4):342-355

Digital marine seismic reflection data acquired in 1973 in the Bay of Pozzuoli, and recently reprocessed, were used to study the volcanological evolution of the marine sector of Campi Flegrei Caldera during the last 37 ka. In order to gain more information, interpretation also involved estimation of the "pseudo-velocity" and the "pseudo-density" from the resistivity logs of two onshore deep exploration wells. The main results are: (1) discovery of ancient pre-18 ka and post-37 ka submarine and mainly effusive volcanic activity, along coeval emission centers located at the edges of Campi Flegrei Caldera; (2) confirmation that the caldera collapse in the marine sector of Campi Flegrei seems strongly controlled by regional NE–SW and NW–SE structural discontinuities; (3) the finding of at least two episodes of collapse in the bay; and (4) identification of a post-18 ka volcanic deflation phase that has caused about 150–200 m of subsidence in the central sector of the Bay of Pozzuoli in the last 18 ka.Editorial responsibilty: T. Druitt  相似文献   

The Status of the Twaite Shad, Alosa agone, in Italy and the Western Balkans     

Pier Giorgio Bianco 《Marine Ecology》2002,23(S1):51-64

Abstract. The twaite shad, Alosa agone , is still quite common in Italy and the western Balkans, but locally is endangered or extinct. Two eco-phenotypes are recognized: the migratory'Cheppia'or'Laccia'and the landlocked'Agone'. The two forms have never been in contact, at least in Italy. The migratory form is more endangered since barriers and dams prevent it from reaching upstream spawning grounds. A few reproductive communities are documented, e. g. in the Po River in Italy and Neretva River in Croatia. Resident stocks have increased to substantial populations in the large lakes of Italy, especially in the last ten years, probably as a result of improved water quality. The landlocked form from northern Italy was successfully introduced into lakes of central Italy about 75 years ago. In Sardinia a population derived from the migratory form was established about 80 years ago in the artificial Lake Omodeo. In Croatia the'Cheppia'seems to live only in the lower course of the Neretva River. In Montenegro,'Cheppia'and'Agone'live in sympatry in Lake Skadar, but a dam built in 1960 caused a strong decline of both forms. The twaite shad is a very variable species, able to modify its morphology and biology according to its adaptation to freshwater or marine biotopes. In the Mediterranean area, only one taxon should be then recognized, Alosa agone (Scopoli, 1786). This will replace Alosa fallax (Lacépède, 1803), a taxon described from the Atlantic drainage area which seems to be distinct from Mediterranean populations. A survey of the distribution of reproductive communities of the migrating form in the Mediterranean area must be carried out.  相似文献   

Private finance for adaptation: do private realities meet public ambitions?     

W. P. Pauw  R. J. T. Klein  P. Vellinga  F. Biermann 《Climatic change》2016,134(4):489-503

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The Arctic Coastal Dynamics Database: A New Classification Scheme and Statistics on Arctic Permafrost Coastlines     

Hugues Lantuit  Pier Paul Overduin  Nicole Couture  Sebastian Wetterich  Felix Aré  David Atkinson  Jerry Brown  Georgy Cherkashov  Dmitry Drozdov  Donald Lawrence Forbes  Allison Graves-Gaylord  Mikhail Grigoriev  Hans-Wolfgang Hubberten  James Jordan  Torre Jorgenson  Rune Strand ?deg?rd  Stanislav Ogorodov  Wayne H. Pollard  Volker Rachold  Sergey Sedenko  Steve Solomon  Frits Steenhuisen  Irina Streletskaya  Alexander Vasiliev 《Estuaries and Coasts》2012,35(2):383-400

Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be strongly affected by changes in currently poorly observed arctic coastal dynamics. We present a geomorphological classification scheme for the arctic coast, with 101,447?km of coastline in 1,315 segments. The average rate of erosion for the arctic coast is 0.5?m? year^?1 with high local and regional variability. Highest rates are observed in the Laptev, East Siberian, and Beaufort Seas. Strong spatial variability in associated database bluff height, ground carbon and ice content, and coastline movement highlights the need to estimate the relative importance of shifting coastal fluxes to the Arctic Ocean at multiple spatial scales.  相似文献   

Heat budget of the upper Arctic Ocean under a warming climate     

Tim Graham  Michael Vellinga 《Climate Dynamics》2013,40(1-2):143-153

The heat budget of the upper Arctic Ocean is examined in an ensemble of coupled climate models under idealised increasing CO₂ scenarios. All of the experiments show a strong amplification of surface air temperatures but a smaller increase in sea surface temperature than the rest of the world as heat is lost to the atmosphere as the sea-ice cover is reduced. We carry out a heat budget analysis of the Arctic Ocean in an ensemble of model runs to understand the changes that occur as the Arctic becomes ice free in summer. We find that as sea-ice retreats heat is lost from the ocean surface to the atmosphere contributing to the amplification of Arctic surface temperatures. Furthermore, heat is mixed upwards into the mixed layer as a result of increased upper ocean mixing and there is increased advection of heat into the Arctic as the ice edge retreats. Heat lost from the upper Arctic Ocean to the atmosphere is therefore replenished by mixing of warmer water from below and by increased advection of warm water from lower latitudes. The ocean is therefore able to contribute more to Arctic amplification.  相似文献