SEISMIC REHABILITATION OF SHORT RECTANGULAR RC COLUMNS

Non-ductile response of structural elements, particularly columns, has been the cause of numerous documented failures during earthquakes. The objective of this experimental study was to evaluate the non-linear behaviour of non-ductile reinforced concrete short columns under lateral cyclic deformations and to evaluate rehabilitation schemes. Three reinforced concrete short columns were tested under cyclic lateral loads and constant axial load. The behaviour and effectiveness of different rehabilitation systems using carbon fibre reinforced polymers (CFRP) were investigated. Two different techniques to improve concrete confinement were used in the two rehabilitated specimens. It was found that it is possible to eliminate the non-ductile modes of failure of short column using anchored CFRP wraps. In addition, an analytical model to predict the confining effect and the total shear resistance of rectangular reinforced concrete columns with anchored fibre wraps was introduced. The confinement model is an extension to an available model for concrete confined by steel reinforcement. The model was used to predict the shear capacity of the tested specimens and has shown good results.     

A FIBRE FINITE BEAM ELEMENT WITH SECTION SHEAR MODELLING FOR SEISMIC ANALYSIS OF RC STRUCTURES

The paper describes the formulation of a non-linear, two-dimensional beam finite element with bending, shear and axial force interaction for the static and dynamic analysis of reinforced concrete structures. The hysteretic behaviour of “squat” reinforced concrete members, in which the interaction between shear and flexural deformation and capacity is relevant for the overall structural performance, is emphasised. The element is of the distributed inelasticity type; section axial-flexural and shear behaviours are integrated numerically along the element length using a new equilibrium-based approach. At section level a “hybrid” formulation is proposed: the axial-flexural behaviour is obtained using the classic fibre discretisation and the plane sections remaining plane hypothesis, the shear response instead is identified with a non-linear truss model and described with a hysteretic stress-strain relationship. The latter contains a damage parameter, dependent on flexural ductility, that provides interaction between the two deformation mechanisms. The element has been implemented into a general-purpose finite element code, and is particularly suitable for seismic time history analyses of frame structures. Analytical results obtained with the model are compared with recent experimental data.     

On the Supposedly Young age of Angara Alluvial Sediments Based on the Findings of Salvage Excavations in the Flooding Area of the Boguchany Hydroelectric Plant

Based on the stratigraphy of Paleolithic sites on the northern Angara, the Upper Pleistocene and Holocene history of the region is reconstructed. Findings of recent salvage excavations in the Boguchany flooding zone as well as the evidence of Quaternary geology, geomorphology, neotectonics, and archaeology jointly disprove the “young Angara” model proposed by G.I. Medvedev and other “geoarchaeologists.” The principal event postulated by that model – the alleged disastrous outburst of the Angara along the Baikal channel 12–7 ka BP is supported neither by the relief nor by the Upper Pleistocene and Holocene sedimentation record nor by the stratigraphy of the Paleolithic sites on the northern Angara.     

The composition of the soda-rich and mixed alkali plant ashes used in the production of glass

Soda-rich plant ashes have been used in the Near East and Egypt in the production of glass and faience from the 4th millennium BC onwards, and mixed alkali plant ashes have been similarly used in western Europe during the 2nd and first half of the 1st millennia BC. In the production of these ashes, the plants of interest are salt resistant, halophytic plants of the Chenopodiaceae family, growing in coastal, salt marsh and desert regions. A primary criterion in selecting ashes for glass and faience production is that the alkalis are predominantly in the form of carbonates, bicarbonates and hydroxides rather than either chlorides or sulphates. In the current paper, previously published data for such ashes are brought together and re-assessed, and new analytical data are presented for ashes produced from plants collected in Egypt, Greece and the UK. For the ashes produced from Salsola kali plants collected from Greece and the UK, the soda to potash ratios (0.3–1.8) do not show any systematic differences between the regions in which the plant was growing, but instead reflect the fact that this species favours the accumulation of K⁺ over Na⁺ ions. Further, the results suggest that S. kali could have been the source of the mixed alkali ashes used in western Europe, if the ashes had first been treated in some way in order to reduce their lime-plus-magnesia contents.     

Sweet potato (Ipomoea batatas) and banana (Musa sp.) microfossils in deposits from the Kona Field System,Island of Hawaii

Analysis of plant microfossils (pollen, phytoliths, starch grains and xylem cells) was carried out on 12 soil samples from a variety of pre-contact archaeological features in South Kona within a portion of what has been termed the Kona Field System, on the Island of Hawaii. The oldest radiocarbon ages of the sampled deposits are 1300–1625 AD and 1310–1470 AD. The pollen and phytolith evidence suggests a change from more to less trees and shrubs in the area as a result of human activity. We found phytoliths of banana (Musa sp.) leaves in most and starch grains and xylem cells of tuberous roots of c.f. sweet potato (Ipomoea batatas) in all of the samples, suggesting that the sampled features were associated with these crops and that both crops were cultivated intensively within the study area. Higher concentrations (volumetric) of starch and xylem in samples from older deposits suggest that cultivation was more intensive then. The apparent absence of starch and xylem remains of other tuberous crops archaeologically identified elsewhere in Polynesia suggests that tuberous cropping within the study area was mono-specific.     

The Huldremose Iron Age textiles,Denmark: an attempt to define their provenance applying the strontium isotope system

Archaeological textiles recovered on two occasions from the Huldremose bog, Denmark, represent some of the best preserved and complete garments from the Danish Iron Age (500 BC–AD 800). In order to address the question regarding the provenance of the textile's raw material, we applied a recently developed method based on strontium isotopes to wool and plant fibres from these ancient garments. Textile plant fibres from Huldremose I find are of non-local provenance, whereas the wool from which the garment was made stemmed from sheep grazing on glaciomoraine soils developed on Cretaceous–Tertiary carbonate platform sediments widely found in Denmark. The Huldremose II find consists of an unusually large and well preserved garment, which is composed of wool from at least three different provenances. One source is again local, whereas the other two sources, characterized by elevated ⁸⁷Sr/⁸⁶Sr ratios, are compatible with geologically older (Precambrian) terrains which are typical for Northern Scandinavia, e.g. Norway or Sweden. Our study suggests that wool and plant fibres were either traded or brought as raw materials for textiles more commonly and over longer distances than previously assumed.     

光纤在博物馆文物陈列照明中的应用方式

光纤照明是一种安全照明,可避免紫外光和红外光对文物的伤害。本文阐述了光纤点照明方式、线照明方式和面照明方式的应用特征,并列举了光纤照明在南京博物院、丹麦国家博物馆、上海博物馆和井冈山革命博物馆等多个应用实例,论述了光纤照明是照明科学性和艺术性的统一。     

中国钢铁工业的诞生考释

中国钢铁工业诞生的问题学术界至今没有统一的认识。按照当今中国钢铁工业协会所定标准,福州船政局所属锤铁厂和拉铁厂应为中国最早的钢铁加工企业,它的创建标志着中国钢铁工业的诞生;青溪铁厂是中国第一家钢铁联合企业;汉阳铁厂则是中国第一家大型钢铁联合企业。     

Plant microfossils in prehistoric archaeological deposits from Yuku rock shelter,Western Highlands,Papua New Guinea

Plant microfossil analysis was carried out on anthropogenic deposits from Yuku rock shelter, possibly occupied from before 14,200 cal. BP to recent times, in the Papua New Guinea Highlands. Elaeocarpus pollen has extremely high percentages throughout. Starch residues of lesser yam (Dioscorea esculenta) and one or more, undifferentiated Dioscorea species were identified, suggesting processing of these taxa since first use of the site. The latter include Dioscorea alata, Dioscorea bulbifera, Dioscorea nummularia and Dioscorea pentaphylla. Pollen and phytoliths of banana (Musa) appear 5200 cal. BP. We cannot differentiate between naturally growing and cultivated yams and bananas. Putative truffle (hypogeous Ascomycotina) spores in the deposits suggest foraging of truffles.     

‘The debatable territory where geology and archaeology meet’: reassessing the early archaeobotanical work of Clement Reid and Arthur Lyell at Roman Silchester

The first large-scale archaeobotanical study in Britain, conducted from 1899 to 1909 by Clement Reid and Arthur Lyell at Silchester, provided the first evidence for the introduction of Roman plant foods to Britain, yet the findings have thus far remained unverified. This paper presents a reassessment of these archaeobotanical remains, now stored as part of the Silchester Collection in Reading Museum. The documentary evidence for the Silchester study is summarised, before the results are presented for over a 1000 plant remains including an assessment of preservation, identification and modern contamination. The dataset includes both evidence for the presence of nationally rare plant foods, such as medlar, and several archaeophytes. The methodologies and original interpretations of Reid and Lyell's study are reassessed in light of current archaeobotanical knowledge. Spatial and contextual patterns in the distribution of plant foods and ornamental taxa are also explored. Finally, the legacy of the study for the development of archaeobotany in the 20th century is evaluated.