Finite Element Analysis of Two Nearby Interfering Strip Footings Embedded in Saturated Cohesive Soils

The issue of interaction between nearby footings is of paramount practical significance. The interference effect should be taken into account since the footing may really be separated from or bounded by other footings on one or both sides. In this regard, this paper studies the effect of two nearby interfering strip footings embedded in saturated cohesive soils, which will help to provide a better understanding of the impact of footing depth on the interference effect. A numerical study is carried out using the finite element program (Midas GTS-NX), and the behavior of closely placed strip footings embedded in the saturated cohesive soils is investigated under the influence of different factors such as the spacing between footings, the depth of footings, soil undrained shear strength, and the groundwater table. It was concluded that the soil cohesion and the footing depth ratio have a notable influence on the interference of closely spaced footings. For all cohesion values, it has been observed that the spacing needed for interference to vanish decreases with an increase in the depth of the footing and water table. In addition, as the S/B ratio increases, the ultimate bearing capacity (UBC) of interfering footings decreases until it reaches the same value as an isolated footing at greater spacing. The UBC is approximately 10% higher at S/B = 1 compared to the isolated footing. However, at S/B = 1, the UBC of two footings achieves a value equal to that of an isolated footing and does not change when the S/B ratio increases. With increasing footing depth, there is an increase in UBC. Finally, the highest values of x were obtained in all cases when Cu = 40 kPa. This indicates that the interaction between footings is greater when the soil is softer. Doi: 10.28991/CEJ-2023-09-03-017 Full Text: PD

Strength Properties of Polymer Reactive Powder Concrete with Waste Materials

Reactive powder concrete, or RPC, outperforms conventional or even high-performance concrete in terms of ultra-high strength and better durability. Several buildings were destroyed in Iraq, and recycling the garbage from these buildings can significantly help reduce waste and environmental pollution as well as serve as a source of aggregate for use in new construction. Reusing garbage and using sustainable building materials are now crucial environmental challenges, so this study aimed to replace the natural fine aggregate, NFA, used in preparations of polymer reactive powder concreter, "PRPC" with recycled aggregates, or RA, from crushed old concrete, COC, in order to make PRPC production more environmentally and sustainably friendly. In this study, RPC is modified by adding styrene butadiene rubber (SBR), a polymer, to the original mixture at a ratio of 13% by weight of cement. This study sought to determine the effect of using COC as recycled fine aggregate (RFA) on the compressive, splitting, and flexural strengths of PRPC. The main objective of this investigation is to study the effect of oil (water, new oil, and waste engine oil) on the compressive and tensile strengths of PRPC with COC and to compare the behavior with that of a control mix (PRPC with NFA). The mixtures were prepared using six different percentages of RFA, replacing 0, 20, 40, 60, 80, and 100% NfA. After 28 days, the six mixes were divided into three groups. The first was still being cured in water, W; the second in waste engine oil, WEO; and the third in kerosene oil, KO. The results showed that using COC as RFA in PRPC was viable, and according to this investigation, the mix with 40% COC replacement with NFA provides the highest values of compressive strength, tensile strength, and flexural strength before and after exposure to liquids (water, new oil, and waste engine oil). Doi: 10.28991/CEJ-2023-09-08-09 Full Text: PD

Y-chromosomal STR variation in Kurds and Arabs population in Iraqi Kurdistan

Background: The Iraqi Kurdistan local population involves more than eight gatherings of tenants. The Muslim Kurds make up most of the population and after that the Yezidi Kurds. Alternate gatherings incorporate Armenians, Assyrian, Chaldea, Syriacs, and little minority of Arab and Turkmen individuals.Methods: A total of 36 unrelated males from the two population groups in Iraqi Kurdistan: Kurds and Arabs were analyzed for eight Y-chromosome STRs (DYS19, DYS392, DYS437, DYS448, DYS456, DYS458, DYS635 and Y-GATA-H4). Total DNA from blood cells was extracted using DNA extraction Kit.Results: A number of genetic parameters such as mean number of alleles, allele frequency, gene diversity, polymorphic information content (PIC), and genetic distance were calculated using Power Marker V3.25 software. The DYS458 had the highest diversity (GD: 0.883), while loci DYS456 and Y-GATA-H4 had the lowest (GD: 0.574). The Dendrogram separated the populations into two main clades, the Kurd group and the Arab group except in one case only from the whole population.Conclusions: This study confirms the discriminating power of high-resolution Y-STR typing and provides first primary dataset on Iraqi Kurdistan samples. The comparison of Kurdish and Arab datasets reveals an interesting overall picture of isolation of Kurdish group. The primers DYS19, DYS448, DYS458, and DYS635 can be considered the best for their high PIC power

ETUDE DES FORMES D’ONDES D’UN RADAR ULB DANS LE CONTEXTE VEHICULAIRE

Le principal problème rencontré pour l’utilisation de la technologie ULB est le choix de la forme d’onde adéquate en fonction de l’application envisagée. Dans cet article, nous présentons le radar ULB utilisé dans le contexte V2V (Vehicle to Vehicle) et les simulations effectuées sous Matlab dans le but de choisir la forme d’onde la plus adéquate au système étudié. Les résultats de simulation nous ont permis de déduire que l’impulsion monocycle donne les meilleurs performances en termes de précision par rapport au polynômes de Geganbauer et  d’Hermite

Engineering Properties of Clayey Soil Stabilized with Lime

Kaolin soil represents the soft clay soil with a depleted bearing capacity and an elevated compressibility level. Thus, in order to hold up civil structures, the bearing capacity of kaolin soil needs to be raised. Several soil improvement procedures are currently available. These include soil replacement, preloading, corduroy and chemical stabilization. However, as these procedures are harmful to the environment, efforts to achieve soil stabilization ought to make use of materials that are environmentally friendly. The utilization of industrial waste that does not have a negative impact on the environment would represent a significant step forward in this area. Among the most frequently employed procedures to achieve soil stabilization is the utilization of a binder such as lime. This study puts forward an array of laboratory investigations to assess the influence of lime on the compressibility and swelling traits of soil. According to the findings, the liquid limit and plasticity index of soil is reduced with the introduction of lime. Pozzolanic reactions transpire due to the siliceous and aluminous nature of the material which has a negligible cementation value and is made up of large particles. This circumstance culminates in a reduction of the liquid limit. With a 9% application of lime, an elevation in the liquid limit was observed (a decrease in other reaction materials). This is attributed to the excessive presence of lime. The optimal water content rose from 20% to 23% with a 5% application of lime. The stabilizer content (lime) reduces the maximum dry density from 1.63 to 1.585 g/cm3. Lime content enhances the compressibility of soft clay by lowering the coefficient of volume compressibility (mv) reduces with increasing stabilizer content and the optimum percent for lime. This is a result of the reaction between lime and soil

RELIABILITY-BASED DESIGN PROCEDURE OF AXIALLY LOADED PILES

Geotechnical engineering involves many different and complex materials and many different mechanisms of behaviour. The direct use of experience as a guide to the prediction and design is effective provided these are understood. Geotechnical engineering is a relatively new science. Its successful application to prediction requires realistic assumptions to be made, and predictions must be tested against reality. Methods of prediction need then to be refined. An example of the importance of making realistic assumptions is examined in this paper. It includes the effects of soil properties on the ultimate capacity of axially loaded piles. Better analysis offers better prediction and better understanding. Both are only possible when reality is modelled. There are occasions when mechanisms are too complex for predictive analysis. Prediction must then be based directly on experience, applied with an understanding of the mechanisms involved. Moreover, methods of analysis may become too sophisticated for everyday use. However, pseudo-analysis, involving standardized methods based on oversimplified and unrealistic mechanisms of behaviour and material properties, is dangerous. The use of engineering experience as a guide to prediction and design may offer a more effective alternative, provided it is based on a realistic understanding of mechanisms and materials. In this paper, a procedure is recommended to estimate the bearing capacity of axially loaded piles based on reliability calculations. The procedure is an extension of the point estimate method in which the expected values of the standard deviation of the capacity and demand functions are calculated. The probability of failure, the reliability, central factor of safety and reliability index are calculated as appropriate. The procedure is then applied to two cases where the pile in the first case is driven in sand while in the second, it is driven in clay