MODELLING OF RC BEAM-COLUMN JOINTS AND STRUCTURAL WALLS

The deformation of beam-column joints may contribute significantly to drift of reinforced concrete (RC) frames. In addition, failure may occur in the joints due to cumulative concrete crushing from applied beam and column moments, bond slip of embedded bars or shear failure as in the case of existing frames with nonductile detailing. When subjected to earthquake loading, failure in RC structural wall is similar to failure of frame joints as it may occur due to cumulative crushing from high flexural stresses, bond slip failure of lap splice, shear failure or a combination of various mechanisms of failure. It is important to include these behavioural characteristics in a simple model that can be used in the analysis of RC frames and RC walls to predict their response under earthquake loading and determine their failure modes.

Global macro models for the beam-column joint and for RC structural walls are developed. The proposed models represent shear and bond slip deformations as well as flexural deformations in the plastic hinge regions. The models are capable of idealising the potential failure mechanism due to crushing of concrete, bond slip or shear with allowance for the simultaneous progress in each mode. The model predictions are compared with available experimental data and good correlation is observed between analytical results and the test measurements.     

ON THE OPTIMAL LOCATION OF SENSORS IN MULTI-STOREYED BUILDINGS

A new approach has been developed for finding optimal location of sensors in 3D multi-storeyed buildings. This approach is based on the compact probabilistic representation of acceleration response in terms of its covariance matrix. For a specified number of sensors, the optimal location has been taken to be the one for which the computed covariance matrix is closest to the exact covariance matrix of the random field constituted by the acceleration response process. It has been found that the determined sensor locations match favourably with those predicted by earlier studies for the special case of shear buildings. Further, the optimality of the determined sensor locations has also been verified by identifying the system parameters from the time series data and comparing them with those of the Finite Element Model.     

GENERATION OF ARTIFICIAL EARTHQUAKE MOTION RECORDS USING WAVELETS AND PRINCIPAL COMPONENT ANALYSIS

In the last century alone two to three million people died in earthquakes; More than 240 000 perish in Tangshan earthquake in China, 20 000 in the Izmit [Ikeya, 2004] 50 000 in India Bhuj earthquake, 100000 in Sumatra and 90000 in Pakistan earthquakes. Earthquake engineering has progressed to the stage where it is now computationally practical and desirable to perform a dynamic analysis of most civil engineering structures. Such an analysis requires the engineer to create an accurate analytical model of the structures as well as prescribe an earthquake input excitation. The design earthquake input excitation for the site under consideration is usually prescribed in the form of response spectra or in the form of an ensemble of artificial earthquake acceleration time histories. There is every need for generating artificial accelerograms since recorded accelerograms are very limited at site. This paper proposes five neural network based models for the generation of artificial earthquake and response spectra using wavelet transforms (WT) and principal component analysis (PCA) where the recorded accelerograms are limited at site of interest. The proposed model is compared with Lee and Han's model. The data for 25 earthquakes are taken for training and 4 for testing. Just like response spectra, this is also a convenient way of obtaining the design solution to a structural dynamics problem and is certainly an important tool.     

INSTANTANEOUS OPTIMAL CONTROL FOR SEISMIC ANALYSIS OF NON-LINEAR STRUCTURES

In this paper, an effective active control algorithm is developed for the vibration control of non-linear structural systems subjected to earthquake excitation. It is an attempt to include the non-linear characteristics of the structural behaviour throughout the entire analysis (design and validation), accounting for the eventual cumulative structural damage and energy dissipation. This is a very important factor since, in current design practice, structures are assumed to behave nonlinearly when subjected to strong ground motion. The proposed algorithm focusses on the instantaneous optimal control approach for the development of the control algorithm where the nonlinearities are brought into the analysis through a non-linear state vector and a non-linear open loop term. A performance index that is quadratic in the control force and in the non-linear states and is subjected to a non-linear constraint equation, is minimised at every time step. The effectiveness of the proposed non-linear instantaneous optimal control (NIOC) strategy is critically evaluated in comparison with currently available active control techniques. Numerical simulation results indicate that the proposed approach provides a significant reduction of the peak response quantities, such as maximum response deformation, maximum response acceleration, ductility of the system, associated with a reduced maximum control force.     

我国出境游客旅行前的信息搜索行为意向研究：基于TAM、TPB与DTPB模型

本文使用TAM、TPB与DTPB模型对我国出境游客旅行前的信息搜索行为意向进行分析发现,态度是影响我国出境游客旅行前信息搜索行为意向的首要因素,其次则是知觉有用性、感知行为控制和主观规范。同时,研究也发现,虽然上述3个模型对行为意向均具有较强的解释力,但从模型解释的变异量、拟合度及简约性来看,TPB模型最为恰适,且修正后的TPB模型解释了行为意向75％的变异。     

New trials in the consolidation of waterlogged archaeological wood with different acetone-carried products

Some acetone-carried consolidants for waterlogged archaeological wood were tested in order to evaluate treatments able to save time and energy. In details, colophony (rosin), two esterified colophonies (Rosin 100^® and Rosin 459^®), a mixture of colophony with PEG 3400 and a vinyl acetate - vinyl versate copolymer (Vinavil 8020S^®) were tested. The treatments were carried out at temperatures of 20 and 35 °C on waterlogged maritime pine, elm, oak and beech. The materials came from the archaeological site of the ancient ships of Pisa (Tuscany, Italy) and were dated back to VII cent. BC – II cent. AD. To evaluate the processes, equilibrium moisture content and dimensional stability of treated wood samples at different relative humidity, and retention of impregnating products were measured; moreover macroscopic and microscopic examination were also run to respectively assess the shape and appearance of treated wood and the way of deposition of consolidants. The results highlighted that natural and modified colophony treatments gave the most satisfactory results both in the maintenance of shape and dimensions of samples and in the stabilization with respect to RH variations. Moreover, the equilibrium moisture contents of samples treated with R100 and R459 were much reduced in comparison to the other consolidants and to untreated archaeological wood. This fact was related to the high retention values of those products that occluded most of the porosity including the microporosity of cell walls. Therefore, in terms of higroscopicity treated wood was more similar to impregnating substances rather than to decayed wood. This fact was considered helpful in contrasting the moisture-related negative effects in cases of eventual faults in the climate control during e.g. exhibition and in protecting treated wood from the risks of new fungal attacks.     

Premature exit from and delayed entrance into the less developed status: An empirical appraisal of the structural funds allocation criterion

This paper investigates the impact of the main criterion employed by the European Commission for the allocation of the largest portion of Structural Funds, based on the threshold of the 75% of European Union (EU) average gross domestic product (GDP) per capita. We focus on the 2014–2020 programming period and on EU-15 regions to analyze if this criterion has penalized some of them, as a consequence of the 2004 EU enlargement, which has represented an exogenous shock in the allocation process, due to the economic backwardness of new member states. Through the application of Synthetic Control Methods and Difference-in-Differences estimators at different geographical scales, we show that regions that did not obtain the less developed status in both the programming period 2007–2013 and 2014–2020, but that would have obtained it in the period 2014–2020 without the 2004 EU enlargement, experienced a significantly lower GDP per capita growth between −10.5% and −5.7%. Conversely, territories that in the period 2014–2020 lost the less developed status, previously obtained in the time frame 2007–2013, were not characterized by a significantly lower economic growth, providing some evidence of the effectiveness of the safety net.     

Technical Strategies for Conservation of Earthen Archaeological Architecture

The preservation of earthen architectural heritage is extremely complex due to the diversity of its constituent materials and potentially rapid physical deterioration. Interventions on historic earthen architecture throughout the world have shown very distinct levels of success, but there is no single procedure or combination of conservation procedures that guarantee success. One of the problems is the lack of knowledge about the behaviour of soil as the material component, and its relationships both with other materials, and associated natural and cultural environments. This article analyses some technical considerations that have influenced the preservation of earthen archaeological remains, through critical analysis of the existing bibliographic references from the proceedings of specialized international conferences that have taken place in the last twenty years.     

THE GROWTH OF LITERACY IN FRANCE DURING THE EIGHTEENTH AND NINETEENTH CENTURIES

ABSTRACT

The Ottoman Empire faced catastrophic events during its period of dissolution which started with the First World War. At the end of this war, the Ottoman lands were shared by the Allied forces. As a reaction to this occupation, the Turkish War of Independence started in 1919 and finished in 1923. The authors aim to examine how these events were reflected in the ?stanbul bourse, using Ottoman government bond prices data between 1918 and 1925. Econometric methodology of Carla Inclan and George Tiao (1994 Inclan, C., and G. Tiao. 1994. Use of the cumulative sums of squares for retrospective detection of changes of variance. Journal of the American Statistical Association 89:913–23.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) identifies several break points, which imply a lower risk for the repayment of the bonds during the end of the First World War and the Turkish War of Independence.     

On the provenience of wood used in the manufacture of snuff trays from San Pedro de Atacama (Northern Chile)

The consumption of hallucinogenic substances is a long-standing tradition in the Americas. San Pedro de Atacama (SPA) in Northern Chile is the archaeological zone with the highest incidence of snuffing implements in the world. Snuff trays from SPA have been studied under a variety of prisms but their provenience, in particular that of the wood used in their manufacture, has not yet been addressed. The delicate nature of trays and their excellent state of preservation call for the use of non-invasive analytical methods. Wood density was used to demarcate a possible range of species and hence as a broad provenience marker, and its value determined for 169 trays from the museum at San Pedro de Atacama. The results showed that although some of the SPA snuff trays studied may have been manufactured with local wood, most of them used exogenous wood as raw material. At this point, it is not possible to ascertain the precise origin of such wood, but Bolivia and NWA appear as likely candidates. Three distinct styles have been defined for SPA trays: Tiwanaku, San Pedro, and Circumpuneño (encompassing the area around the Puna de Atacama and including SPA). The effect of style on density points to different sources of wood in Tiwanaku style trays and trays in San Pedro and Circumpuneño styles. As expected from geographically and temporally dynamic patterns of interaction of SPA with neighboring regions, diachronic differences in wood density distributions were found. Tray manufacturing technique was not dependent on wood density, suggesting that the skill of artisans and the quality of their tools allowed them to use any type of wood for their art work, independent of its complexity.