Effects of Soil Stiffness on Seismic Response of Buildings Considering Soil-Pile-Structure Interaction

© 2017 19th ICSMGE Secretariat. All rights reserved. In this study, a fifteen-storey moment resisting building sitting on an end-bearing pile foundation in soil socketed in rock is selected in conjunction with four values of shear wave velocity. Effects of corresponding shear strength are studied through numerical modelling using finite difference software FLAC3D. Fully nonlinear dynamic analysis under the influence of Northridge earthquake is performed. The results indicate that soil plasticity should be taken into account while conducting dynamic analysis considering soil-pile-structure interaction. However, the dynamic response of the structure regarding base shear, foundation slab rotation, pile lateral deflection and structure lateral deflection is sensitive to the effect of shear strength with the increase in shear wave velocity and corresponding shear modulus. Also, the results show that the dynamic response of structures sitting on end-bearing pile foundations depends not only on base shear attracted by the superstructure but also on the foundation slab rotation. Therefore, to perform realistic seismic analysis and to conduct reasonable seismic design of mid-rise building resting on end-bearing pile foundations, the consideration of foundation slab rotation is essential

Bridge Pile Response to Lateral Soil Movement Induced by Installation of Controlled Modulus Columns

© 2016 The Authors. Published by Elsevier B.V. Controlled modulus columns (CMC) for ground improvement are installed using a hollow stem displacement auger to induce lateral soil displacement effect, followed by grout injection. While the method reduces spoils, the excessive lateral soil displacement may damage adjacent structures. Although there has been growing interest in quantifying such effects, only a handful of studies have been attempted. This paper presents the results of a numerical investigation on the CMC installation effect on an existing bridge pile using the three-dimensional finite difference software package FLAC3D. It has been found that when the CMC is long and the existing bridge pile is slender, the pile bending moment and pile lateral movement, induced by the CMC installation effect, can be significant

Molecular Study of PER and VEB Genes is Multidrug Resistant Pseudomonas aeroginosa Isolated From Clinical Specimens in Isfahan/Iran and their Antibiotic Resistance Patterns

Abstract: Background & Aims: Duo to clinical use of antibiotics, pseudomonas aeruginosa strains with multiple drugs resistance have significantly increased throughout the world. Betalactamase production is one of the Mechanisms involved in resistance to pseudomonas aeruginosa resulting in many problems in the treatment of infections caused by this bacterium. The aim of this study was molecular analysis of PER and VEB genes in Pseudomonas with multiple resistance isolated from clinical samples in Isfahan/Iran. Methods: In whole, 98 isolates of Pseudomonas aeruginosa from various clinical specimens were identified by biochemical tests and the antibiotic susceptibility of the identified strains were determined using Kirby-Bauer method. PCR was performed on the samples to evaluate the presence or absence of PER and VEB genes. Results: Among 98 strains of Pseudomonas aeruginosa, 73 samples (73%) were multiple drugs resistant and all of them were cefotaxime, cefepime and ceftazidime resistant. Prevalence of PER and VEB genes were respectively 5 (6.84%) and 8 (10.9%). Conclusion: Considering high prevalence of multi-drug resistant Pseudomonas aeroginosa, it is essential to reduce these pathogens in hospitals through controlling PER and VEB genes transfer. Keywords: Beta-lactamase, Pseudomonas aeruginosa, PER, VE

Comparison of Coupled Flow-deformation and Drained Analyses for Road Embankments on CMC Improved Ground

© 2016 The Authors. Published by Elsevier B.V. The use of controlled modulus columns (CMC) is gaining increased popularity in the support of rail and road bridge approach embankments on soft soils. The further columns are driven into the competent firm soils, the further the design will rely on the inclusions to take the bulk of the vertical loads, as they become rigid inclusions. The advantage of this design approach is that it produces increased control over the settlement, but as a result the columns will attract greater loads, including bending moment and shear force in situations where non-uniform loading or ground conditions exist. The load on the composite soil-CMC is uniformly distributed by the upper layer of granular load transfer platform (LTP), which also includes a layer of reinforcement. Finite difference program FLAC3D has been used to numerically simulate an embankment on the improved ground with end-bearing CMC. A geosynthetic reinforcement layer has been simulated using the inbuilt FLAC3D geogrid element. In this paper, a comparison has been made between the drained and coupled flow-deformation analyses. The force in the reinforcement layer, in particular, has been compared for the two analysis approaches. It was found that according to the numerical simulation, the drained analysis provides lower estimates of the settlement, lateral displacement; and therefore, predicts less tension in the geosynthetic layer

Characterization of Iranian grapevine cultivars using microsatellite markers

Sixty-two grapevine (Vitis spp.) accessions from Iran and the USA were characterized at 9 highly polymorphic microsatellite loci using fluorescent primers and a capillary electrophoresis fragment sizing system. The number of alleles observed per locus ranged from 4 to 16 and heterozygosity values ranged from 0.47 to 0.86. Genetic similarity was estimated for each pair of accessions as the proportion of shared alleles. A phenogram constructed from genetic dissimilarity values revealed three clusters, one each for table grapes, wine grapes and rootstocks. The phenogram also revealed three clonal sets (Askari, Bidane and Yaghoti) as well as some synonyms and homonyms among Iranian table grape cultivars.

Installation Effect of Controlled Modulus Columns on Nearby Existing Structures

© 2016 ASCE. Controlled modulus columns (CMC) ground improvement technique is a novel approach to reduce ground settlement. To install CMC, a rotary displacement auger is used to form a vertical cylindrical cavity, by displacing the surrounding soils laterally, followed by grout injection. While the method reduces spoil generation, excessive lateral soil displacement may damage the adjacent structures and freshly-grouted CMCs. Although there has been growing interest in quantifying such effects, only a handful of studies have been attempted. This paper presents results of a numerical investigation on the CMC installation effect on an existing bridge pile using the three-dimensional finite difference software package FLAC3D. The bridge pile response to the lateral soil movement induced by the CMC installation are presented and discussed

Genetic Relationships among Pistacia Species Studied By Morphological Characteristics and RAPD Marker

Abstract: The aim of this research was to study 33 Pistachio accessions and determine their genetic relationships. Thirty-one morphological characters (17 quantitative and 14 qualitative) together with Randomly Amplified Polymorphic DNA (RAPD) marker data were used for this purpose. Factor analysis was used to determine the effective characteristics and the number of main factors which determined seven main factors. Grouping of pistachio accessions by these factors was performed by Ward's method. Among 77 random decamer primers tested, 12 showed good amplification and polymorphism, and a total of 130 markers were produced that 118 were polymorphism. Grouping by morphological characteristics was compared with the results from RAPD analysis which did not produce a significant correlation

Documentary analysis of Persian papers published on rural housing in Iran in the recent decade

A careful study of the dimensions of human life in rural areas and its accurate recognition for the design and construction of suitable houses require a special look at rural housing research in terms of physical, technical, economic, cultural, social and environmental aspects. This research analyzes the records in the literature on rural housing by referring to scientific journals in the field. The findings of the study indicate that most of the research has been conducted in a descending order in the provinces of North Khorasan, Fars, Zanjan, and Sistan and Baluchestan The series of studies carried out can be classified under nine issues including rural house designing and modelling, sustainable housing, structural-functional changes in houses, native architecture of Iranian houses, planning and policy, facilities and credits, housing rehabilitation, analysis of housing indices, and geographic analysis of housing elements. The findings of this research indicate three main approaches adopted in the study of rural housing in Iran. As much as 83.58% of all the research has been conducted with quantitative methodology, 13.43% with qualitative method, and just 2.98% (two cases) with combined methodology. Also, as the results show, of all the rural housing research in the country, 34.22% is retrospective, 11.94% is prospective, and 53.73% has addressed the existing housing situation

Seed germination and seedling establishment of some wild almond species

Wild almond species are important genetic resources for resistance to unsuitable condition, especially drought stress. They have been used traditionally as rootstocks in some areas of Iran. So far, 21 wild almond species and 7 inter species hybrids have been identified in Iran. To study seed germination and seedling establishment of some of these species, three separate experiments were designed. In the first experiment, the application of gibberellic acid (GA3) (0, 250, 500 and 750 ppm) for 24 h was studied on germination characteristics of four wild almond accessions after stratification at 5 ± 0.5°C in Perlite media. Germination percentage, index vigor and root initiation factors were different in almond accessions, but were not affected by hormonal treatments. In the second experiment, seeds of another six wild almond accessions were stratified to compare their germination ability. Germination percentage, index vigor and root initiation were different among accessions significantly. In the last experiment, the establishment and vigor of 14 accessions from eight almond species have been evaluated in plastic bags in outdoor conditions. Two ecotypes of Prunus spp. had the highest stem diameter and length at all growing stages.Keywords: Amygdalus, germination percentage, index vigor, root initiation, stem length, stem diameter