潮湿土遗址隔水防潮技术对比研究

潮湿土遗址的破坏,很大程度上是受水的影响,目前国内几个潮湿土遗址经常使用的防水隔水措施主要有:挡水墙、隔水廊道、拱券法和抽水法。经过对几种方法进行总结评价,可看出拱券法是最有效的方法。     

清代塞外围场格局与动物资源盛衰

清代的塞外围场,建于山深林茂之区,有丰富的动植物资源,地域相连,功能各异,政治军事地位十分重要。清皇室决定着围场资源的利用方式和占有形式,康乾时期不间断的军事演练式的行围对围场动物资源衰减有重要影响,嘉道停围后,骑射演武的军事功能荡然无存,但动物资源衰减依旧势不可遏。塞外围场分布格局、资源存在结构及分配形式改变,围场体系完结。     

城墙命运变迁与遗产保护思考

近五六十年来,人们对古城墙的态度发生了巨大的变化,与之密切相关的城墙命运也是如此,经历了一个从拆除到日渐重视保存、从趋于保护到热衷于修复和重建的历史过程。本文对这一过程及其重要人事进行了梳理,并分析了相关重要影响因素。同时,基于城墙命运巨大变化的历史考察,对快速城市化过程中的城市文化遗产保护进行了多方面的思考。     

成都市龙泉驿五代前蜀王宗侃夫妇墓

1998年,成都市文物考古研究所等对成都龙泉驿区青龙村的一座砖室墓进行发掘。墓葬为较大型的长方形双室券顶砖墓,墓圹平面呈亚字形,两墓室均由封门墙、墓室、棺床、耳室和肋拱组成。此墓是迄今发掘的除王建永陵之外的最高级别的前蜀重臣和分封亲王墓葬,为前蜀墓葬制度的研究提供了重要的资料。     

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.     

Saxton's Maps of England and Wales: The Accuracy of Anglia and Britannia and Their Relationship to Each Other and to the County Maps

ABSTRACT

From measurements of the graticules on Saxton's two general maps of England and Wales—the atlas map Anglia and the wall map Britannia—together with other evidence, it is argued that neither map was drawn according to any specific projection, but that both were effectively produced as ‘flat-earth’ maps with the graticules superimposed afterwards. Digital versions of Saxton's maps and of a modern map, the 1:1 million Ordnance Survey transport map, are used in a number of comparisons by means of the computer program MapAnalyst. These comparisons allow the scales of the two Saxton maps to be determined. They also show that the maps are of almost the same accuracy in terms of the positioning of settlements, typically within about 4.6 kilometres, in spite of a difference in scale of a factor of about 3.6. This fact and the direct comparison of the two Saxton maps in MapAnalyst show that they are basically the same map, and it is concluded that a version of the wall map was the first to be drawn and that Anglia is a reduced copy prepared for the atlas. The lengths of Saxton's miles as used on the two maps are calculated and compared with other determinations. The relationship between the two general maps and the county maps is briefly considered, and it is provisionally concluded that the relationship is a close one.     

STRUCTURAL CONTROL ALGORITHMS IN EARTHQUAKE RESISTANT DESIGN

The dynamic finite element equations of a two-dimensional structure made of axial-flexural frame elements with tendon-driven actuators have been derived. A critical review of classical optimal control theory is made with respect to its application to the control of structure under seismic excitations. Seven control algorithms, including two newly proposed algorithms, have been described, investigated and discussed. The need of an optimal observer, Kalman filter, is discussed. The validity of separation theorem applicable to the optimal stochastic control of structure for earthquake resistance is shown. How the control system perform under the circumstances of actuator saturation is also shown. Several numerical examples are worked out to demonstrate and compare the efficiency and limitations of those control algorithms.     

NONLINEAR ANALYSIS OF REINFORCED CONCRETE SHEAR WALL UNDER EARTHQUAKE LOADING

A constitutive model for predicting the cyclic response of reinforced concrete structures is proposed. The model adopts the concept of a smeared crack approach with orthogonal fixed cracks and assumes a plane stress condition. Predictions of the model are compared firstly with existing experimental data on shear walls which were tested under monotonic and cyclic loading. The same model is then used in the finite element analysis of a complete shear wall structure which was tested under a large number of cyclic load reversals due to earthquake loading at NUPEC's Tadotsu Engineering Laboratory. Two different finite element approaches were used, namely a two-dimensional and a three-dimensional representation of the test specimen. The ability of the concrete model to -reproduce the most important characteristics of the dynamic behaviour of this type of structural element was evaluated by comparison with available experimental data. The numerical results showed good correlation between the predicted and the actual response, global as well as local response being reasonable close to the experimental one.     

SEISMIC BEHAVIOUR OF A R/C WALL: NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION

This paper describes the numerical simulation of the seismic behaviour of a mock-up of a six-floor building, constituted by two parallel R/C walls and experimentally tested on a shaking table. Within the scope of an international benchmark the mock-up was submitted to three earthquakes with intensities up to 0.71 g, which induced nonlinear behaviour in the concrete and reinforcement. For the numerical simulations concrete is discretised with 2D finite elements, and its behaviour reproduced via a constitutive model with two scalar damage variables. Steel rebars are discretised with 2-noded truss elements, and their constitutive behaviour under cyclic conditions reproduced by the Menegottb-Pinto model. Specific attention is devoted to Rayleigh damping, focusing on two different strategies: (i) disregarding the damping contribution, or (ii) adopting a damping matrix that takes into account the stiffness changes during the nonlinear analyses. Main results and strategies for simulating the benchmark axe presented, with emphasis on the comparison between the numerical and the experimental results, which show good agreement when the damping contribution is neglected.     

A PRACTICAL MODEL FOR SEISMIC ANALYSIS OF REINFORCED CONCRETE SHEAR WALL BUILDINGS

A simple macro-model for reinforced concrete shear walls is proposed, which consists of spring elements representing flexure and shear behaviour. The model for flexural behaviour is based on section analysis, while the model for shear behaviour is based on key parameters of the flexural behaviour. Four wall test specimens are selected to evaluate the reliability of the model. Modelling parameters for the backbone curves and the hysteretic rules are examined by conducting static and time history analyses, with the hysteretic response of a test specimen compared to that calculated using the proposed model. Results show some differences between measured and calculated shear force versus shear distortion relationships, but the model is acceptable because the differences do not significantly affect calculated global response. Parametric studies are also conducted to examine the influence of modelling parameters on seismic demand and capacity, which are the major design parameters for structural performance evaluation. Differences due to variation in modelling parameters are not significant, further indicating that the proposed model is reasonable.