A High-Performance Quadrilateral Flat Shell Element for Seismic Collapse Simulation of Tall Buildings and Its Implementation in OpenSees

Shear walls are important lateral force-resistant components of tall buildings. Hence, a reliable numerical model that can accurately represent the mechanical characteristics and large deformations of shear walls is critical for realistic collapse simulation of tall buildings. Based on the theory of generalized conforming element, a high-performance quadrilateral flat shell element, NLDKGQ, accounting for the large deformation using the updated Lagrangian formulation, is proposed herein and implemented in OpenSees. The reliability of NLDKGQ is validated using classical benchmark problems and reinforced concrete specimens. In addition, its capability in simulating the collapse of a tall building is also demonstrated.     

DEM Algorithm for Progressive Collapse Simulation of Single-Layer Reticulated Domes under Multi-Support Excitation

In this paper, the Member Discrete Element Method (MDEM) is modified and perfected for three aspects: the algorithm itself, loading and computational efficiency, and to accurately and quantitatively simulate the progressive collapse for large-span spatial steel structures. In addition, the corresponding computational programs are compiled. First, from the perspective of the method, a meshing principle for discrete element models is determined, a treatment for material nonlinearity and strain rate effect is proposed, and a damping model is established. Next, the Displacement Method is introduced to determine the multi-support excitation for the MDEM, and then motion equations of particles under multi-support excitation are derived. On this basis, the specific process of gravitational field loading is presented. Furthermore, parallel implementation strategies for the MDEM based on OpenMP are constructed. Finally, the collapse simulation of a 1/3.5-scaled single-layer reticulated dome shaking table test model under multi-support excitation is carried out. The comparison demonstrates that the ultimate load and failure mode as well as the complete collapse time of the numerical results are consistent with the experimentally measured responses, and the configuration variations from member buckling and local depression until collapse failure are fully captured. Moreover, the displacement time-history curves obtained using MDEM are almost identical to the experimental measurements, and there is a nuance only in the amplitude. It is verified that MDEM is capable of precisely addressing the collapse failure for large-span spatial steel structures. Additionally, the failure mechanism for structures of this type is naturally revealed.     

First record of a fossil selenariid bryozoan in South America

López-Gappa, J., Pérez, L.M. & Griffin, M. February 2017. First record of a fossil selenariid bryozoan in South America. Alcheringa XX, xxx-xxx. ISSN 0311-5518.

Selenariidae Busk 1854 (Bryozoa) is considered endemic to Australia and New Zealand. Here we describe a new species of Selenaria Busk 1854 from the lower Miocene Monte León Formation (Patagonia, Argentina). Selenaria lyrulata sp. nov. is characterized by autozooids with a lyrula-like, anvil-shaped cryptocystal denticle, opesiular indentations and lateral condyles, as well as avicularia with a shield of fused costae. This is the first record of a selenariid bryozoan in South America.

Juan López-Gappa [lgappa@macn.gov.ar] CONICET—Museo Argentino de Ciencias Naturales. Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina; Leandro Martín Pérez [pilosaperez@gmail.com] and Miguel Griffin [patagonianoyster@gmail.com], CONICET—División Paleozoología Invertebrados, Museo de La Plata. Paseo del Bosque s/n, B1900FWA, La Plata, Argentina.     

Modelling of hydrology and potential population levels at Bronze Age Jawa,Northern Jordan: a Monte Carlo approach to cope with uncertainty

An annual water balance model for Wadi Rajil, in Northern Jordan, is used to simulate the ancient water supply system for the Early Bronze Age site of Jawa. The model includes: water delivery from the catchment; local pond storage; and water demand for people, animals and irrigation. A Monte Carlo approach is used to incorporate the uncertainty associated with a range of factors including rainfall, evaporation, water losses and use. The stochastic simulation provides estimates of potential population levels sustainable by the water supply system. Historical precipitation estimates from a Global Circulation Model, with uncertainty bounds, are used to reconstruct the climate at Jawa in the Early Bronze Age (EBA). Model results indicate that the population levels in the predicted wetter conditions during parts of the EBA could have risen to ∼6000 and may have been higher in wet years. However, palaeoclimatic proxies also suggest prolonged droughts in the EBA; and during these periods the water management system was unable to provide adequate supply for a population of 6000. The utility of Monte Carlo based hydrological modelling as a tool within archaeological science is discussed.     

Aretusa: continuity,rupture and space for intervention (1944–46)

This article focuses on the cultural activity of Aretusa (1944–46), a journal that was deeply connected to the inner circle of philosopher and politician Benedetto Croce (1866–1952). The article analyses the role played by periodical editors Francesco Flora (1891–1962) and Carlo Muscetta (1912–2004) in shaping the mission and direction of this journal. By drawing on Pierre Bourdieu’s theory of habitus, and the notion of hysteresis in particular, this study details the factors influencing the aesthetic dispositions, political positioning and the wider impact of historical circumstances on the cultural practice of each editor while at the helm of the review.     

计算机辅助设计（CAD）在文物修复中的运用

通过计算机辅助设计(CAD)在文物修复这门传统工艺中的运用,进一步提高了在文物修复过程中预想修复效果和制定最佳修复方案的精确性。并借助计算机辅助设计在二维平面、三维立体效果方面的特长,模拟文物破损处复原、去除和保留不同颜色物质、创建和复制器物残缺部分及预览器物安装情况等效果。这样不仅为文物修复提供有利帮助,还使这门传统工艺与当今先进计算机技术得到有机结合。修复实践表明,对那些变形较大,又不想进行破坏性修复的文物来说,三维模拟修复就是唯一的修复方法。     

西安鼓楼油饰彩画主要病害分析

为了对油饰彩画进行科学保护,对具有代表性的西安鼓楼油饰彩画病害进行了调查分析．发现存在的主要病害有失光、褪变色、粉化、龟裂、起甲、脱落、烟熏、降尘等。结合实验室模拟实验对病害成因进行了初步探讨,认为导致病变的内因是木基层含水率及地仗制作工艺;外界环境因素为紫外线、温湿度、大气降尘、油烟熏及降雨等。分析结果可为彩画保护提供科学依据。     

Stochastic Quantification of Soil-Shallow Foundation-Structure Interaction

This article highlights soil-structure interaction (SSI) effects on the seismic structural response accounting for uncertainties in the model parameters and input ground motions. A probabilistic Monte Carlo methodology was used to conduct approximately six million dynamic time-history simulations using an established rheological soil-shallow foundation-structure model. Considering the results yields outcomes that contradict prevailing views of the always beneficial role of SSI. In other words, the likelihood of having amplification in structural response due to SSI is large enough that it cannot be readily ignored. This research provides a significant first step towards reliability-based seismic design procedures incorporating foundation flexibility.     

Der erste Europäische Straßenatlas

ABSTRACT

Imitations of famous Dutch wall maps originally produced in Amsterdam by F. de Wit and W. J. Blaeu have recently been rediscovered in Italy. In Bologna, in the archive of Opera Pia dei Poveri Vergognosi, is a set of Blaeu's four wall maps of the continents, engraved on new plates by Pietro Todeschi and published by Giuseppe Longhi. The value of the discovery lies in the completeness of the exemplars, which also bear the publisher's imprint and date of publication, hitherto unknown: Europe 1677; Africa 1678; Asia 1679; America 1679/1680(?). An undated version of de Wit's world wall map, also published by Longhi, has come to light in the same archive. A copy of the same map, this time published by Giovanni Giacomo de' Rossi in Rome in 1675, was then found in Modena in the Seminario Metropolitano. Comparison of the two copies has provided a date for Longhi's undated issue; Longhi's map came after de' Rossi's, that is after 1675.     

The Italian Left in search of ideas: the rediscovery of the political ideas of the Action Party

In the wake of the collapse of 'really-existing' socialism and against a background of the growing influence of neo-liberal political thought, European socialist parties - and especially the former communist parties - have found it crucially important to reassert their liberal credentials. This explains the interest displayed by the Italian Left in liberal socialism, Dahrendorf 's New Liberalism and American liberalism, and especially in what is now called the 'Third Way'. In Italy, these developments have resulted in a genuine example of 'history's revenge'. The political ideas associated with the Action Party (PdA), which long played a Cinderella role in Italian politics and culture, have moved back to centre stage. This article examines how Italian leftist parties like the Democrats of the Left (DS) have been realigned to take into account the ideas of liberal socialism proposed by thinkers like Carlo Rosselli. It also explores how,since 1989, parties of the Italian Left have tried to appropriate the Actionist past and its mission, and why,after a long period of deliberate neglect, the Actionist agenda has again become the subject of lively debate.