Mass eccentricity effects on the torsional response of inelastic buildings

This paper investigates the role of accidental mass eccentricities on the inelastic torsional behaviour of multi-storey asymmetric buildings with a mixed type lateral load resisting system subjected to the Erzincan-1992 and Kobe-1995 ground motions. The numerical modelling results show that the effects of spatial variations of mass eccentricities are lower and smoother in the inelastic rather than the elastic state of deformation, but both the elastic and inelastic torsional response is pointing to the same optimum location of the key element for which the torsional response of the structure is minimized

Rock-burst occurrence prediction based on optimized naïve bayes models

Rock-burst is a common failure in hard rock related projects in civil and mining construction and therefore, proper classification and prediction of this phenomenon is of interest. This research presents the development of optimized naïve Bayes models, in predicting rock-burst failures in underground projects. The naïve Bayes models were optimized using four weight optimization techniques including forward, backward, particle swarm optimization, and evolutionary. An evolutionary random forest model was developed to identify the most significant input parameters. The maximum tangential stress, elastic energy index, and uniaxial tensile stress were then selected by the feature selection technique (i.e., evolutionary random forest) to develop the optimized naïve Bayes models. The performance of the models was assessed using various criteria as well as a simple ranking system. The results of this research showed that particle swarm optimization was the most effective technique in improving the accuracy of the naïve Bayes model for rock-burst prediction (cumulative ranking = 21), while the backward technique was the worst weight optimization technique (cumulative ranking = 11). All the optimized naïve Bayes models identified the maximum tangential stress as the most significant parameter in predicting rock-burst failures. The results of this research demonstrate that particle swarm optimization technique may improve the accuracy of naïve Bayes algorithms in predicting rock-burst occurrence. © 2013 IEEE

Dataset for "The use of the hollow cylinder apparatus to study stress paths relevant to railway track foundations"

Dataset supports the paper : A.Mamou, W. Powrie, J. Priest, C.Clayton The use of the hollow cylinder apparatus to study stress paths relevant to railway track foundations 7th International Symposium on Deformation Characteristics of Geomaterials 26th &ndash; 28th June 2019</span

The role of clay content on the response of railway track foundations during free-to-drain cyclic changes in principal stress rotation

This paper investigates the role of clay content on the response of railway track foundation materials during free-to-drain cyclic changes in principal stress rotation. Four sand clay mixes typical of an in situ railway track foundation were investigated, with clay contents varying from 7% to 24%. It was found that increasing the clay content from 7% to 24%, reduced the volumetric contraction of the mixes during cyclic shear stress increases below a cyclic shear threshold. Volumetric strain reduced with both increasing intergranular and global void ratios. Non linear regression analysis showed generally high correlations between volumetric strain and both intergranular and global void ratios, with the relationship between volumetric strain and intergranular void ratio showing less scatter

The use of the hollow cylinder apparatus to study stress paths relevant to railway track foundations

This paper presents and discusses results from a series of hollow cylinder tests, carried out to investigate the effects of principal stress rotation on the resilient response of soils in stress paths relevant to railway track foundations. Four sand-clay mixes, typical of the gradation of an in situ railway track foundation, were investigated. The aim of the research was to investigate the magnitudes of shear stress cycles for which the associated cyclic rotations of the principal stress direction may have a significant effect on the long-term stability of a railway track foundations

Behaviour of saturated railway track foundation materials during undrained cyclic loading

This paper presents the results of a series of hollow cylinder tests carried out to investigate the undrained behaviour of saturated railway track foundation materials during cyclic loading involving principal stress rotation. Four sand-clay mixes representative of real railway track foundation materials were investigated. It was found that moderate additions of clay (up to ~14% by weight) increased the cyclic shear stress threshold at which significant excess pore pressures started to accumulate. After the cyclic shear stress threshold had been exceeded, the rate of pore pressure increase with the logarithm of the axial strain was greatest for the material having a clay content of 11%. Excess pore pressure generation reduced with increasing intergranular and global void ratio, with the global void ratio being perhaps the more useful indicator because of the reduced amount of scatter and higher correlation of the idealized relationship.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Data for &quot;The role of clay content on the response of railway track foundations during free-to-drain cyclic changes in principal stress rotation&quot;

Data used in the paper &quot;The role of clay content on the response of railway track foundations during free-to-drain cyclic changes in principal stress rotation&quot;, TRGEO_2019_64</span

Dataset for The effects of drainage on the behaviour of railway track foundation materials during cyclic loading

The dataset presents the results of a series of hollow cylinder tests carried out to investigate the role of drainage conditions on the response of railway track foundation materials during cyclic loading. Three sand-clay mixes were tested.</span

Suitability of empirical equations for estimating permanent settlement of railway foundation materials subject to cyclic loading with principal stress rotation

This paper uses the results of a series of laboratory tests with cyclic principal stress rotation to assess the suitability of a number of empirical equations for estimating the development of plastic settlements in railway track foundations. The laboratory tests were carried out on three sand-clay mixes representative of railway track foundation materials, in both free-to-drain and undrained conditions. The results of a non-linear regression analysis demonstrate that the drainage conditions are the key factor affecting the estimation accuracy of the models, with the clay content playing a secondary role. The correlation coefficient was generally higher in free-to-drain than in undrained conditions, and reduced slightly with increasing clay content.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

The effects of drainage on the behaviour of railway track foundation materials during cyclic loading

This paper presents the results of a series of hollow cylinder tests carried out to investigate the role of drainage conditions on the response of railway track foundation materials during cyclic loading. Three sand–clay mixes were tested. It was found that, below a certain cyclic shear stress threshold, and depending on the drainage conditions, changes in principal stress direction should not adversely affect the cyclic stability of a railway foundation. However, significant stiffness degradation and failure may occur if this cyclic shear stress threshold is exceeded. The cyclic shear stress threshold increased with moderate additions of clay per unit volume of sand, and reduced significantly when specimen drainagewas prevented. For the materials tested, the cyclic shear stress threshold in free-to-drain conditions was generally similar to the cyclic shear stress in the soil immediately below a 0·3 m deep ballast bed, but comfortably greater than the cyclic stress at a depth of 1 m below the sleeper base. In undrainedconditions, the cyclic shear stress threshold was generally similar to the cyclic shear stress at a depth of 1 m below the sleeper base. This has implications for the suitability of such materials for railway track foundations