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Shell foundations are often used to raise the carrying capacity of a structure on weak soils. In cases where large superstructure loads must be transferred to poorer soils, shell foundations are more cost-effective than ordinary shallow foundations. Advances in the study and design of shell-type foundations have shown their superiority over traditional footings in poorer soils. The current study aims to investigate shell shape’s influence on ultimate load capacity. Seven footing types’ models were created along with an appropriate testing box. The soil needed for the study was from the region north of Mosul city, classified as silt with low plasticity (sandy silt) soil. A laboratory model experimentally determined the ultimate load capacities for inverted and upright conical, inverted and upright pyramid, and hemispherical shell foundations on silty soil. The achieved results were associated with those for conventional flat squares and circles. According to the findings, the “upright conical” shell footing has a load capacity of 12.7 kN, higher than the other foundations, and its efficiency was 51%. When comparing foundations, the “upright pyramidal” shell footing has better settling characteristics and a settlement factor of 0.017. As the shell factor decreases, the shell foundation begins to behave more like a flat foundation, which reduces the maximum load capacity of the shell foundation.

In most construction buildings, the footings (especially separate footings) come closer to each other, causing an interfering effect. This interference significantly influences both settlement and bearing capacity. The idea of this research has come after reviewing the available studies in this field and due to the importance of taking into account the construction sequence and the embedded depth for the adjacent footings in different levels. This research has studied the evaluation of settlements for adjacent square footings with different embedded depths numerically. The effect of embedded depth, the spacing between the footings, and the construction sequence have been considered variables. The embedded depth and the spacing values have varied from 0.5 to 1.0 and 1.5 to 2.5 time the footing width, respectively. The studied variables have been numerically simulated with 3-dimensional modeling using the PLAXIS software. The results have illustrated that the settlement and the bearing capacity have increased as the spacing between the adjacent footings have decreased. This behavior is attributed to the interfering effects between footings. According to the efficiency factor, it is better to construct the adjacent footings at different levels. Furthermore, the adjacent footings have not tilted under the effects of arrangement patterns and the footing depth levels. [ABSTRACT FROM AUTHOR]

Abstract We report three cases of symptomatic stenosis of the great vessels or supra-aortic trunks successfully treated surgically with aorto-subclavian and aorto-innominate bypass. Two were performed via manubriotomy and a third case via standard median sternotomy because of concomitant coronary revascularisation. There was complete symptomatic relief on follow-up, and radiological imaging confirmed good flow in the grafts and post-stenotic arteries.

Natural fibers had been used as reinforcing elements since 3000 BC. Recently, reinforcing soil with natural fibers has become of key significance in investigations. Hay fiber has been selected for this study because of its tensile strength and bulk availability. Thus, it is anticipated that the strength of reinforced soil would increase and cracking of the soil would be minimal. To verify that, a series of experimental tests have been performed on natural and hay fiber-reinforced soil specimens. Four different percentages of hay fibers (0.25, 0.5, 1.0 and 1.5% by weight) were used in this study and various experimental test, including unconfined compression test, P-wave velocity test, free swell test, soil-water retention test and microstructural test, were conducted on natural and hay fiber-reinforced soil specimens. Results show that the strength behavior of soil specimens depends considerably on the hay fiber content. It is found that the unconfined compressive strength (UCS) increases as the hay fiber content increases up to 1.0%, then it decreases for higher hay percentage used in the current study. It is noticed that the interaction between hay fiber and soil compounds could control the mechanism of the reinforcement benefit. Consequently, the swelling potential decreases significantly as the hay percent increases. The water-holding capacity of soil specimens increases with hay content. Furthermore, the parameters of soil water retention curve (SWRC): volumetric water content and corresponding air entry value depend directly on the texture of the hay fiber. Microstructural test explains the variations in SWRC parameters. It is observed that these parameters are significantly affected by the change in the pore size distribution of hay fiber-reinforced soil specimens. [ABSTRACT FROM AUTHOR]

This work aims at studying the pore water pressure development within a thin clay core in an earth dam. The study consists of two parts; a parametric study for general thin clay core (with and without chimney drains), followed by a case study of BADUSH dam. Different operation levels and storage times with the possibility for rapid rise in water level are considered for the case study. Finally the effect of an earthquake on pore water pressure in this types of a dam was also studied as a case study. Two dimensional finite element analysis was used to simulate pore water pressure development by GEO-SLOP software taking into consideration saturated /unsaturated conditions. Results showed that the presence of a chimney drain plays an effective role in dissipation of the pore water pressure. In the case of BADUSH dam, a high pore water pressure development was observed, in 8 days as a consequence of a rapid rise of water level, and it must be taken into account when designing dams. Also results show that the pore water pressure in the range of (175-145 kPa) through the typical section and approximately between (25-50 kPa) for the two other sections at the end of construction time, making the height and construction time of the dam are the most effective factors affecting pore water pressure development. [ABSTRACT FROM AUTHOR]