Shear Vulnerability of Historical Reinforced-Concrete Structures

Modern buildings have been characterized by the rapid spread of reinforced concrete as a novel and versatile building material. Within the assessment of existing buildings, the most sensitive structures are those designed in the first half of the 20th century, when the theory of reinforced concrete and the detailing rules were not yet well established. This study considers the issues related to the gradual understanding of the vulnerability at a territorial scale of structural typologies designed only for vertical loads. In particular, the shear behavior of the buildings in the period between 1920 and 1960 is investigated. The shear strength control of the structural elements of an open-air stadium in Southern Italy is carried on according to Eurocode 2, the American Concrete Institute Code, ACI 318R–2008, and a method based on Arslan’s equation. The results are compared with those included in the original calculus report according to the 1930 Royal Decree-Law (RDL 18/7/1930).     

Experimental Evaluation of Seismically and Non-Seismically Detailed External RC Beam-Column Joints

An experimental investigation was undertaken to study the seismic performance of external reinforced concrete (RC) beam-column joints having representative details for mid-rise RC frame buildings in developing countries such as Iran that were designed and constructed prior to the 1970s. Three half-scale external RC beam-column joints were tested by applying lateral cyclic loading of increasing amplitudes. Tested specimens were comprised of one unit having seismic reinforcement detailing in accordance with the seismic requirements of ACI 318-11, and two units having non-seismic reinforcement detailing in accordance with the 1970s construction practice in many developing countries, such as Iran. Two typical defects were considered for the non-seismic units, being the absence of transverse steel hoops and insufficient bond capacity of beam bottom reinforcing bars in the joint region. Test results indicated that the non-seismically detailed specimens had a high rate of strength and stiffness degradation when compared to the seismically detailed specimen, which was attributed primarily to the joint shear failure or bond failure of the beam bottom bars. The non-seismically detailed specimens also showed a 30% reduction in both average strength and ductility and a 60% loss of energy dissipation capacity in comparison to the seismically detailed specimen.     

SEISMIC RELIABILITY ASSESSMENT OF EXISTING REINFORCED CONCRETE BUILDINGS

Structures designed according to earlier codes with inadequate seismic provisions have not performed satisfactorily during recent earthquakes. The seismic performance of an existing three-storey reinforced concrete building designed according to the 1963 ACI 313-63 is evaluated and compared to the performance of a similar frame designed according to current code provisions. Non-linear static and dynamic analyses of the reinforced concrete frames are conducted. In this study, a probabilistic approach is adopted where a large number of artificially generated ground motion records is used as input motion to the structure. The results of the analysis indicated the probability of various degrees of damage to be expected when the existing frame is subjected to different ground motion levels. This information is useful in the design of the required rehabilitation scheme to provide an identified level of protection.     

Experimental Evaluation of Seismic Performance of Squat RC Structural Walls with Limited Ductility Reinforcing Details

This article describes an experimental study carried out on of reinforced concrete (RC) walls of less confining reinforcement than that recommended by ACI 318. A total of eight RC walls with boundary elements comprising of five walls with aspect ratio of 1.125 and three walls with aspect ratio of 1.625 were tested by subjecting them to low levels of axial compression loading and simulated seismic loading, to examine the structural performance of the walls with limited transverse reinforcement. Conclusions are reached concerning the failure mode, drift capacity, strength capacity, components of top deformation, and energy dissipation characteristics of walls on the seismic behavior with limited transverse reinforcement. The influences of axial loading, transverse reinforcement in the wall boundary elements, and the presence of construction joints at the wall base on the seismic behavior of walls are also studied in this paper. Lastly, reasonable strut-and-tie models are developed to help in understanding the force transfer mechanism in the walls tested.     

Seismic Design Issue of Corner Slab-Column Connection

Design criteria of slab-column connections in the ACI Building Code [2011] were mostly developed from experimental results of interior connections. When dealing with corner slab-column connections, supplementary documents published by ACI Committee 352 and Committee 421 provide better explanations than the ACI Building Code [2011] and become useful references for practical engineers. However, different design values can be obtained using approaches recommended by different documents. In this article, a summary of this issue is presented. Among several design parameters discussed in this article, bi-axial moment, gravity shear ratio and column rectangularity have more significant effect to enlarge the discrepancy.     

Comparing closed system, flow-through and fluid infiltration geochemical modelling: examples from K-alteration in the Ernest Henry Fe-oxide–Cu–Au system

Potassic alteration of rocks adjacent to, and within the Ernest Henry Fe‐oxide–Cu–Au deposit is used here as a test case to investigate fluid–rock interactions using various equilibrium dynamic geochemical modelling approaches available in the HCh code. Reaction of a simple K–Fe–(Na,Ca) brine (constrained by published fluid inclusion analysis) with an albite‐bearing felsic volcanic rock, resulted in predicted assemblages defined by (i) K‐feldspar–muscovite–magnetite, (ii) biotite–K‐feldspar–magnetite, (iii) biotite–quartz–albite and (iv) albite–biotite–actinolite–pyroxene with increasing rock buffering (decreasing log w/r). Models for isothermal–isobaric conditions (450°C and 2500 bars) were compared with models run over a T–P gradient (450 to 200°C and 2500 to 500 bars). Three principal equilibrium dynamic simulation methods have been used: (i) static closed system, where individual steps are independent of all others, (ii) flow‐through and flush, where a part of the result is passed as input further along the flow line, and (iii) fluid infiltration models that simulate fluid moving through a rock column. Each type is best suited to a specific geological fluid–rock scenario, with increasing complexity, computation requirements and approximation to different parts of the natural system. Static closed system models can be used to quickly ascertain the broad alteration assemblages related to changes in the water/rock ratio, while flow‐through models are better suited to simulating outflow of reacted fluid into fresh rock. The fluid infiltration model can be used to simulate spatially controlled fluid metasomatism of rock, and we show that, given assumptions of porosity relationships and spatial dimensions, this model is a first‐order approximation to full reactive transport, without requiring significant computational time. This work presents an overview of the current state of equilibrium dynamic modelling technology using the HCh code with a view to applying these techniques to predictive modelling in exploration for mineral deposits. Application to the Ernest Henry Fe‐oxide–Cu–Au deposit demonstrates that isothermal fluid–rock reaction can account for some of the alteration zonation around the deposit.     

Norfolk Island: history,people, environment,language. By Peter Mühlhäusler and Joshua Nash

The Apotheosis of Captain Cook. European Mythmaking in the Pacific. By Gananath Obeyesekere. Princeton, Princeton University Press, 1992. xvi, 251 pp. ISBN 0–691–05680–3 How ‘Natives’ Think. About Captain Cook For Example. By Marshall Sahlins. Chicago, The University of Chicago Press, 1995. 318 pp. ISBN 0–226–73368–8     

LIFE HISTORY AS METHOD: AN ITALIAN-CANADIAN FAMILY IN AN INDUSTRIAL CITY

The paper reviews the nature and uses of life history as method, grounding it in both philosophy and theory- that is, neo-pragmatism and symbolic interactionism, respectively. It goes on to review the practical issues of doing life histories before presenting a case study of an Italian-Canadian family in an industrial city. The paper concludes with two commentaries: the first on how the case informs on ethnic identity and identity retention, the second on what the life history approach means for the practice of research.
Cet article examine la nature et les emplois du vécu humain en tant que système, système dont la source est dans la phitosophie et la théorie - c'est-à-dire, respectivement, dans le néo-pragmatisme et ľon;interactionisme symbolique. II examine ensuite les résultats pratiques obtenus par ľon;analyse de vécus humains, avant de présenter ľon;étude du cas ďon;une famille italo-canadienne dans une ville industrielle. Le document conclut par deux commentaires: le premier, sur la façon dont le cas nous renseigne sur ľon;identité ethnique; le second, sur ľon;apport à la pratique la recherche de cette approche basée sur le vécu humain.     

PSHA for Broad-Band Strong Ground-Motion Hazards in the Saronikos Gulf,Greece, from Potential Earthquake with Synthetic Ground Motions

We perform a probabilistic seismic hazard analysis (PSHA) for broad-band strong ground motion within the Saronikos Gulf region, Greece, from potential earthquakes along the 30 km long Aigina fault in the northern part of the Gulf. We perform the PSHA utilizing empirical Green’s functions (EGFs) merged with synthetic Green’s functions (SGFs) along with models of finite rupture in place of standard “attenuation relations.” Our approach considers all significant magnitudes for PSHA and full broadband ground motion simulations. Calculations are source and site specific, and could reduce uncertainties in estimating standard engineering parameters. We use a range of rupture scenarios for all significant magnitude earthquakes along the fault. The hazard calculation is for frequencies 0.0– 15.0 Hz. Recordings of small earthquakes from an onshore/offshore local seismic array were used as EGFs for frequencies of 1.5–15.0 Hz, the finite difference code E3D was utilized to synthesize SGFs for frequencies 0.0–1.5 Hz, and an algorithm for merging the EGFs with SGFs was developed. The full-waveform calculations are important for non-linear dynamic analysis of structures in the coastal zone and potential hazard to long period structures. Results of proposed PSHA identify 2%, 10%, and 50% hazard at the selected sites of Saronikos Gulf.

Finally, we compare our PSHA results to those obtained by standard practice which involves prediction equations (GMPEs) recently developed in the Next Generation Attenuation (NGA) project and empirical predictive attenuation relations proposed for Greece. We believe that differences with the NGA results are due to site- and source-specific information utilized in this study, and incorporation of this information may significantly reduce the uncertainty in seismic hazard calculations.     

Effect of SMA Braces in a Steel Frame Building

Pull-back and shaking table test results on a simple model of a three-storey structure that includes shape memory alloys (SMA) copper-based dampers are presented and discussed. The model corresponds to a rigid-framed steel structure and the dampers to austenite CuAlBe wires inserted as bracing at each story. The inclusion of the dissipators in the structure increases the percentage of critical damping from 0.59% for the bare case to 5.95% for the braced system. At the same time, the structural stiffness increases making the first fundamental frequency change from 2.5–3.7 Hz (0.4–0.27s). The net effect of these two factors is a 30–60% reduction of peak relative displacements compared to the ones obtained without dissipation devices when the structure is subjected to earthquake records. Depending on records frequency contents, a reduction of the peak accelerations to near 58% also can be obtained. Additionally, a crude nonlinear analytical model has been studied that can predict the earthquake responses reasonably well.     

Seismic Behavior of RC Wide Beam-Column Connections Under Dynamic Loading

In this article, the seismic behavior of RC wide beam-column connections designed primarily for gravity loads is evaluated experimentally. A 2/3 scale model of one exterior and one interior connection is constructed and subjected to seismic simulations on a shaking table until collapse. The results of the tests indicate that: (a) the drift at yield is from 3 to 6 times higher than, for example, the 0.5% admitted by Eurocode 8 to satisfy the “damage limitation requirement;” (b) the beam-column joints do not fail; (c) the torsion in the spandrel beams governs the overall load-displacement relationship of the exterior connections and limits the ultimate strength. Based on the test results, a nonlinear model for predicting the hysteretic behavior and the failure of the connections is suggested. The model can be implemented in a computer code for evaluating the vulnerability of this type of structure through nonlinear dynamic response analyses.     

Predictive Tri-Linear Benchmark Curve for In-Plane Behavior of Adobe Walls

In the present study, numerical simulations are conducted to estimate the in-plane response of adobe walls subjected to pseudo-static cyclic loading based on the finite element code ABAQUS. The simplified micro-modeling approach is adopted and an interface model reported in ABAQUS material library is applied as material model for zero-thickness interface elements. The comparison between obtained results and field test data results in good agreement. Parametric studies are carried out to evaluate the effectiveness of independent parameters changes on response of adobe walls. It is noted that mechanical properties of joints and adobe units play an active role on in-plane behavior of walls. A tri-linear benchmark curve is proposed to predict the response of aforementioned walls. In this regard, a statistical study is performed to derive the predictive tri-linear benchmark curve. The regressive analysis on 59 numerical models resulted in proposing predictive models. Finally, by comparing tri-linear curves obtained from the regressive analysis, numerical analysis, and experimental study, appropriate accuracy of theoretical model can be found.     

THE SIMULATION OF URBAN SYSTEM DYNAMICS IN ATLANTIC CANADA, 1951–1991

A dynamic urban model is used to study the post-war evolution of the Atlantic Canada urban system. The computer-based simulation model is calibrated for the period 1951-86 and then employed to predict the 1991 population of each cma and ca within the system. The simulation results show that, to a large extent, the evolution of the system can be understood in terms of endogenous system dynamics rather than exogenous events. Specifically, competition among the cities of the region is a significant factor in the urban system evolution. The high degree of abstraction of the model means that data requirements for application are minimal, and the calibration procedure is relatively simple. The successful predictions show that the model can yield useful results in spite of its simplicity.
Un modèle dynamique est employé afin ďétudier ľévolution du système urbain de la région atlantique du Canada depuis 1951. Le modèle de simulation est ďabord calibré sur la periode 1951-86, et ensuite utilisé pour générer une prévision de la population en 1991 de chaque rmr et ar dans la région. Les résultats montrent que ľévolution démographique du système peut être expliqué, pour la plupart, par la dynamique inhérente du système. Plus précisement, le processus de concurrence économique et démographique entre les villes de la région est décisif; les événements exogène sont ďune moindre importance. Le modèle est plutot simple et abstrait; par conséquent, son application exige relativement peu de donnés, et le procédé calibration est relativement simple. La qualité des prévisions déographiques indique que ce genre de modèle, malgrésa simplicité peut êre utile.     

Evaluation of Side Boundary Effects on Dynamic Numerical Modeling for Centrifugal Model Tests

Four different boundary conditions consisting of fixed nodes, motion of roller only in the z or the x direction, and equivalent motion of two side boundaries were applied with a finite element code to simulate seismic behavior of two foundation conditions consisting of dry loose and dense sands. Comparing numerical results with physical model tests indicates that data obtained from the finite element code when considering soil nonlinearity with a sand model based on the tij concept have acceptable agreements with those from dynamic centrifuge tests regardless of the boundary conditions. The results from the boundary conditions of roller in the x direction and equivalent motion of two side boundaries agree well with the experimental data in wave peaks. The two side boundary conditions also keep the ground middle undisturbed and provide the results that are similar to those obtained from the wave amplification experimental data. For numerical simulations of centrifuge model tests, the side boundary condition with roller in the x direction is recommended because of low computation time and high simulation quality.     

'This stalwart fellow of five lands and two seas': The Life of Fukushima Yasumasa

Abstract

Although known primarily for his lone horseback ride from Berlin to Vladivostok in 1892–93, Fukushima Yasumasa's career encompassed more than just this one remarkable ride. Born in 1852, Fukushima was caught up in the 1867 civil war, before beginning a military career that took him to almost all corners of the globe. In addition to his service during the 1894–95 Sino-Japanese and 1904–05 Russo-Japanese Wars, Fukushima played an important part in the development of Anglo-Japanese and Japanese-Mongolian relations in the early twentieth century, an aspect of his career that has been largely overlooked. This article re-examines Fukushima's career.     

LOCAL CHANGES IN LINGUISTIC BALANCE IN THE BILINGUAL ZONE: FRANCOPHONES DE L'ONTARIO ET ANGLOPHONES DU QUÉBEC

The issue of minority populations and linguistic change for anglophone and francophone groups in Quebec and Ontario is very important, affecting relationships between the groups and individual perceptions of social power. This paper begins an analysis of linguistic change in the transition or contact zone of bilingualism along the Quebec-Ontario border in the period 1961-86. Written in both languages, it describes changes in absolute numbers and percentage share of the total population of the minority group, anglophones in Quebec and francophones in Ontario. It defines regions of change, and, combining the two measures in a series of graphs, shows levels of change at the local level.
La géographie des populations anglophone et francophone àľintérieur de la zone de transition que constituent ľEst ontarien et le Sud du Québec a sensiblement changé au cours des derniers trente ans. Cet article, rédigé dans les deux langues, décrit ces changements àľéchelle locale sur la base de la comparaison des donnees sur la langue maternelle des recensements del 961 et de 1986. Ľétude identifie les municipalités où les changements dans les nombres au sein des populations minoritaires ont été les plus significatifs ainsi que celles ù ces changements ont le plus affecté le rapport minorité-majorité. Elle met en lumière certains profils de changement et décrit les caractères ethno-linguistiques et géographiques des localités qui en sont représentatives. Elle permet, enfin, de comparer ľévolution des populations franco-ontarienne et anglo-québécoise & ľéchelle locale.     

宁波保国寺大殿风振性能研究

为了更科学地保护我国传统木构建筑,需要研究我国江南地区传统木构建筑的风振性能,为此,以江南地区最古老、保存最完整的佛教木构建筑——保国寺大殿的主殿为例进行风振性能研究。首先基于三维激光扫描获得的真实可靠的保国寺大殿的几何信息,采用SAP2000有限元软件建立主殿的有限元模型,并进行动力特性分析。再利用MATLAB软件编写脉动风速时程,并将风压作用于有限元模型上分析,得到主殿的风振响应。得到结构模态、位移时程曲线、位移谱曲线、加速度响应,并对时程位移风振系数和规范风振系数进行对比。结构的振动响应主要由前三阶振型控制,在强风荷载作用下,最容易出现的变形就是南北向振动、东西向振动和扭转振动;各个典型节点的最大位移均在侧向位移容许值内;迎风面阑额中心位移最大、屋面上半部次之、屋面下半部及檐柱柱头最小;主殿相连的两个部分的加速度相差较多,屋面和屋身的连接节点应成为日后保国寺大殿的保护重点;时程风振系数变化与规范风振系数的变化规律不同是因为结构横向刚度分布不均匀;时程风振系数是规范风振系数的1.2~1.4倍,这是由于按照规范计算风振系数的过程中只考虑了第一阶振型的影响而忽略其他所有振型的结果;规范风振系数的计算只适用于形状、质量沿高度不变的高耸结构,不适用于类似本研究中的低矮木构传统房屋结构。     

IN THE STEPS OF 'GENTEEL LADIES': WOMEN TOURISTS IN THE CANADIAN ROCKIES, 1885-1939

In most accounts of tourism in the Canadian Rockies, women have been neglected. Correspondingly, there have been few attempts to integrate research on tourism history with recent perspectives from social-cultural geography. Travel narratives and related ephemera are used to highlight selected women's roles in early mountain tourism. Considering how touristic experiences were contrasted with nontourist social practices, via dress and notions of 'appropriate' female behaviour, interrelationships between tourism, culture, and society are also proposed. Gender constructs may influence touristic meanings and values. It is thus essential to further scrutinize these frameworks.
Dans la plupart des récits traitant du tourisme dans les montagnes Rocheuses, les femmes ont été quelque peu négligées. Pareillement, rares sont les tentatives ďintégration de la recherche sur ľhistoire du tourisme et des perspectives récentes issues de la géographie socio-culturelle. Les récits de voyage et bagatelles du genre servent à accentuer les rles de quelques héroïnes dans les débuts du tourisme de montagne. Les expériences touristiques étant en contraste avec les pratiques sociales non touristiques - le code relatif à la tenue vestimentaire et au comportement féminin « de bon aloi >> notamment, les relations réciproques entre le tourisme, la culture et la société sont également proposées. Les construits liés au sexe pourraient influer sur les significations et les valeurs touristiques. Il est done essentiel de poursuivre ľanalyse de ces structures.     

The ‘Pacific-First’ Alternative in American World War II Strategy

R.J. OVERY. The Air War, 1939–1945. London, Europa Publications, 1980. Pp. xn, 263. £12.50; H. PENROSE. British Aviation; Widening Horizons, 1930–1934. London, Her Majesty's Stationery Office and the Royal Air Force Museum, 1979. Pp.viii, 340. £7.95; British Aviation; Ominous Skies, 1935–1939. London, Her Majesty's Stationery Office and the Royal Air Force Museum, 1980. Pp. vm, 318. £7.95.     

Volcanic politics: Executive–legislative relations in Britain, 1997–2005

The parliamentary decline thesis overstates the dominance of the executive. The relationship between the executive and legislature is actually far more complex and balanced than is commonly recognised. After exploring recent developments in Australia and New Zealand, this article draws upon an audit of parliamentary modernisation in Britain since the election of New Labour in 1997 and suggests that a reforming parliament occurred during 2001–05 in which an executive with a majority of 166 was forced to acquiesce in the introduction of a raft of reform measures in the House of Commons that were designed to shift the balance of power. At the same time, the ‘transitional’ House of Lords displayed a new-found zeal and activism in a way that further frustrated the executive's control of parliament. This is not to overstate the degree of change: party loyalty remains the primary glue in the executive–legislative relationship and the executive remains dominant. However, it does suggest that in the British context the executive must still work within the limits and constraints of the parliamentary framework.