Seismic performance assessment and base-isolated floor protection of statues exhibited in museum halls     

Stefano?SoraceEmail author  Gloria?Terenzi 《Bulletin of Earthquake Engineering》2015,13(6):1873-1892

A study concerning the evaluation of seismic response of statues exhibited in art museums, and a base-isolated floor strategy for their enhanced protection, are presented in this paper. Attention is particularly focused on statues made of small tensile strength materials, whose behaviour is simulated by a smeared-crack finite element approach. Seismic performance is assessed by referring to four levels specially postulated herein, and namely: (1) Rest conditions; (2) No rocking; (3) Damage control; and (4) Collapse prevention. The response is investigated via incremental dynamic analysis, by progressively increasing the amplitude of the ground motion histories adopted as inputs, and by relating output data to the limit conditions fixed for the above-mentioned performance levels. The assessment procedure is applied to a demonstrative case study, represented by a marble statue to be exhibited in the museum wing situated at the ground level of a medieval castle in Italy, according to an architectural hypothesis of partial rebuilding and reuse of the stronghold. The design solution for the base-isolated floor consists in a system of double-friction pendulum isolators. The finite element model constitutive laws and parameters, the dynamic analyses carried out in fixed-base and base-isolated floor conditions, and the practical implementation of the assumed performance assessment criteria are reported for the statue examined, along with a selection of technical details of the floor design.  相似文献   

A cyclic UH model for sand     

Wan Zheng 《地震工程与工程振动(英文版)》2015,14(2):229-238

A simple cyclic elastoplastic constitutive model for sand is proposed based on the UH model for overconsolidated clay. The proposed model has the following features. First, in order to describe the stress-induced anisotropy in sand, a rotational hardening rule is introduced for the evolution of the yield surface axis with development of plastic deviatoric strain in the principal stress space. Second, the relationship between the rotational axis and stress-induced anisotropy is modeled by introducing the slope of rotational axis into the yield function. The fl atness of the yield surface can be determined by the slope of rotational axis. Finally, a revised unifi ed hardening parameter is proposed to incorporate the stress-induced anisotropy. The model capability in describing the cyclic response of sand is verifi ed by comparing the simulations with available test results.  相似文献   

The structural characteristics,age of origin,and tectonic attribute of the Erguna Fault,NE China   总被引：1，自引：0，他引：1  

Han?Zheng  XiaoMeng?SunEmail author  DeFeng?Zhu  JingXiong?Tian  Song?He  YingDe?Wang  XuQing?Zhang 《中国科学:地球科学(英文版)》2015,58(9):1553-1565

The Erguna Fault runs along the east bank of the Erguna River in NE China and is a large-scale ductile shear zone comprising granitic mylonites. This paper reports on the geometry, kinematic indicators, and 40Ar/39 Ar biotite ages of the granitic mylonites, to constrain the structural characteristics, forming age, and tectonic attribute of the Erguna ductile shear zone. The zone strikes NE and records a top-to-the-NW sense of shear. A mylonitic foliation and stretching lineation are well developed in the mylonites, which are classified as S-L tectonites. Logarithmic flinn parameters(1.18–2.35) indicate elongate strain which approximates to plane strain. Kinematic vorticity numbers are 0.42–0.92 and 0.48–0.94, based on the polar Mohr diagram and the oblique foliation in quartz ribbons, respectively, suggesting that the ductile shear zone formed under general shear, or a combination of simple and pure shear. According to finite strain and kinematic vorticity analyses, the Erguna Fault is a lengthening-thinning ductile shear zone that formed by extension. The deformation behavior of minerals in the mylonites indicates that the fault was the site of three stages of deformation: an initial stage of middle- to deep-level, high-temperature shear, a post-stress recovery phase of high-temperature static recrystallization, and a final phase of low-temperature uplift and cooling. The 40Ar/39 Ar plateau ages of biotite from the granitic mylonites are 106.16 ± 0.79 and 111.55 ± 0.67 Ma, which constrain the timing of low-temperature uplift and cooling but are younger than the ages of metamorphic core complexes(MCCs) in the Transbaikalia-northeast Mongolia region. Using measured geological sections, microtectonics, estimates of finite strain and kinematic vorticity, and regional correlations and geochronology, we conclude that the Erguna Fault is an Early Cretaceous, NNE-trending, large-scale, sub-horizontal, and extensional ductile shear zone. It shares a similar tectonic background with the MCCs, volcanic fault basins, and large and super-large volcanic-hydrothermal deposits in Transbaikalia-northeast Mongolia and the western Great Khingan Mountains, all of which are the result of overthickened crust that gravitationally collapsed and extended in the Early Cretaceous after plate collision along the present-day Sino-Russia-Mongolia border tract.  相似文献   

Chemometric Interpretation on the Occurrence of Endocrine Disruptors in Source Water from Malaysia          下载免费PDF全文

Veerasingan Armugam Santhi  Hafizan Juahir  Ananthy Retnam  Ali Mohd Mustafa 《洁净——土壤、空气、水》2015,43(6):804-810

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Comparative Performance of Water Hyacinth (Eichhornia crassipes) and Water Lettuce (Pista stratiotes) in Preventing Nutrients Build‐up in Municipal Wastewater          下载免费PDF全文

Zubaidah Ismail  Siti Zulaikha Othman  Kim Hing Law  Abdul Halim Sulaiman  Roslan Hashim 《洁净——土壤、空气、水》2015,43(4):521-531

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Salinity Tolerance in Wheat Cultivars Is Related to Enhanced Activities of Enzymatic Antioxidants and Reduced Lipid Peroxidation          下载免费PDF全文

Abdul Khaliq  Muhammad Zia‐ul‐Haq  Faizan Ali  Farhena Aslam  Amar Matloob  Abubakr Navab  Saddam Hussain 《洁净——土壤、空气、水》2015,43(8):1248-1258

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Biodegradation of 2,4‐Dichlorophenoxyacetic Acid Contaminated Soil in a Roller Slurry Bioreactor          下载免费PDF全文

Yasmen A. Mustafa  Hayder M. Abdul‐Hameed  Zainab Abdul Razak 《洁净——土壤、空气、水》2015,43(8):1241-1247

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Geospatial and geostatistical approach for groundwater potential zone delineation   总被引：1，自引：0，他引：1       下载免费PDF全文

Javed Mallick  Chander Kumar Singh  Hussein Al‐Wadi  Mohd Ahmed  Atiqur Rahman  Satyanarayan Shashtri  Saumitra Mukherjee 《水文研究》2015,29(3):395-418

Over the past few decades, groundwater has become an essential commodity owing to increased demand as a result of growing population, industrialization, urbanization and so on. The water supply situation is expected to become more severe in the future because of continued unsustainable water use and projected change in hydrometeorological parameters due to climate change. This study is based on the integrated approach of remote sensing, geographical information system and multicriteria decision‐making techniques to determine the most important contributing factors that affect the groundwater resources and to delineate the groundwater potential zones. Ten thematic layers, namely, geomorphology, geology, soil, topographic elevation (digital elevation model), land use/land cover, drainage density, lineament density, proximity of surface water bodies, surface temperature and post‐monsoon groundwater depth, were considered for the present study. These thematic layers were selected for groundwater prospecting based on the literature; discussion with the experts of the Central Ground Water Board, Government of India; field observations; geophysical investigation; and multivariate techniques. The thematic layers and their features were assigned suitable weights on Saaty's scale according to their relative significance for groundwater occurrence. The assigned weights of the layers and their features were normalized by using the analytic hierarchy process and eigenvector method. Finally, the selected thematic maps were integrated using a weighted linear combination method to create the final groundwater potential zone map. The final output map shows different zones of groundwater potential, namely, very good (16%), good (35%), moderate (28%) low (17%) and very low (2.1%). The groundwater potential zone map was finally validated using the discharge and groundwater depth data from 28 and 98 pumping wells, respectively, which showed good correlation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Coupled ‘storm‐flood’ depositional model: Application to the Miocene–Modern Baram Delta Province,north‐west Borneo          下载免费PDF全文

Daniel S. Collins  Howard D. Johnson  Peter A. Allison  Pierre Guilpain  Abdul Razak Damit 《Sedimentology》2017,64(5):1203-1235

The Miocene to Modern Baram Delta Province is a highly efficient source to sink system that has accumulated 9 to 12 km of coastal–deltaic to shelf sediments over the past 15 Myr. Facies analysis based on ca 1 km of total vertical outcrop stratigraphy, combined with subsurface geology and sedimentary processes in the present‐day Baram Delta Province, suggests a ‘storm‐flood’ depositional model comprising two distinct periods: (i) fair‐weather periods are dominated by alongshore sediment reworking and coastal sand accumulation; and (ii) monsoon‐driven storm periods are characterized by increased wave‐energy and offshore‐directed downwelling storm flow that occur simultaneously with peak fluvial discharge caused by storm precipitation (‘storm‐floods’). The modern equivalent environment has the following characteristics: (i) humid‐tropical monsoonal climate; (ii) narrow (ca <100 km) and steep (ca 1°), densely vegetated, coastal plain; (iii) deep tropical weathering of a mudstone‐dominated hinterland; (iv) multiple independent, small to moderate‐sized (10² to 10⁵ km²) drainage basins; (v) predominance of river‐mouth bypassing; and (vi) supply‐dominated shelf. The ancient, proximal part of this system (the onshore Belait Formation) is dominated by strongly cyclical sandier‐upward successions (metre to decametre‐scale) comprising (from bottom to top): (i) finely laminated mudstone with millimetre‐scale silty laminae; (ii) heterolithic sandstone–mudstone alternations (centimetre to metre‐scale); and (iii) sharp‐based, swaley cross‐stratified sandstone beds and bedsets (metre to decimetre‐scale). Gutter casts (decimetre to metre‐scale) are widespread, they are filled with swaley cross‐stratified sandstone and their long axes are oriented perpendicular to the palaeo‐shoreline. The gutter casts and other associated waning‐flow event beds suggest that erosion and deposition was controlled by high‐energy, offshore‐directed, oscillatory‐dominated, sediment‐laden combined flows within a shoreface to delta front setting. The presence of multiple river mouths and exceptionally high rates of accommodation creation (characteristic of the Neogene to Recent Baram Delta Province; up to 3000 m Ma⁻¹), in a ‘storm‐flood’‐dominated environment, resulted in a highly efficient and effective offshore‐directed sediment transport system.  相似文献   

Iron isotope fractionation in subduction-related high-pressure metabasites (Ile de Groix,France)   总被引：1，自引：0，他引：1  

Afifé?El KorhEmail author  Béatrice?Luais  Etienne?Deloule  Damien?Cividini 《Contributions to Mineralogy and Petrology》2017,172(6):41

Characterisation of mass transfer during subduction is fundamental to understand the origin of compositional heterogeneities in the upper mantle. Fe isotopes were measured in high-pressure/low-temperature metabasites (blueschists, eclogites and retrograde greenschists) from the Ile de Groix (France), a Variscan high-pressure terrane, to determine if the subducted oceanic crust contributes to mantle Fe isotope heterogeneities. The metabasites have δ⁵⁶Fe values of +0.16 to +0.33‰, which are heavier than typical values of MORB and OIB, indicating that their basaltic protolith derives from a heavy-Fe mantle source. The δ⁵⁶Fe correlates well with Y/Nb and (La/Sm)_PM ratios, which commonly fractionate during magmatic processes, highlighting variations in the magmatic protolith composition. In addition, the shift of δ⁵⁶Fe by +0.06 to 0.10‰ compared to basalts may reflect hydrothermal alteration prior to subduction. The δ⁵⁶Fe decrease from blueschists (+0.19 ± 0.03 to +0.33 ± 0.01‰) to eclogites (+0.16 ± 0.02 to +0.18 ± 0.03‰) reflects small variations in the protolith composition, rather than Fe fractionation during metamorphism: newly-formed Fe-rich minerals allowed preserving bulk rock Fe compositions during metamorphic reactions and hampered any Fe isotope fractionation. Greenschists have δ⁵⁶Fe values (+0.17 ± 0.01 to +0.27 ± 0.02‰) similar to high-pressure rocks. Hence, metasomatism related to fluids derived from the subducted hydrothermally altered metabasites might only have a limited effect on mantle Fe isotope composition under subsolidus conditions, owing to the large stability of Fe-rich minerals and low mobility of Fe. Subsequent melting of the heavy-Fe metabasites at deeper levels is expected to generate mantle Fe isotope heterogeneities.  相似文献