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Foundation analysis and design
01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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Journal Article•
TL;DR: In this article, preliminary soil tests were carried out in order to determine the physical properties and the bearing capacity of the soil in Yenagoa, Bayelsa State, Nigeria, using both raft and pile foundations.
Abstract: This work involved the designs and analyses of the foundation of a 5-storey building in Yenagoa, a water-logged area of Bayelsa State, (Nigeria), using both raft and pile foundations. Preliminary soil tests were carried out in order to determine the physical properties and the bearing capacity of the soil. These tests were Dutch cone penetrometer tests, Borehole characteristics test involving standard penetration test, particle size distribution tests, direct shear test, triaxial tests and consolidation tests. The Dutch cone penetrometer tests recorded resistance to cone penetration of 345-355kg/cm 2 . The Borehole characteristic tests showed that the top soil was dry grayish mottled clay, followed by soft silty/sandy clay up to about 6m depth. Below 6-7m depth was sand. The clay end bearing minimum pressure was 54kN/m 2 and maximum pressure was 68kN/m 2 . Sand end bearing minimum pressure was 416kN/m 2 and maximum was 697kN/m 2 . The clay skin friction ranged from 10kN/m 2 to 13kN/m 2 . The sand minimum skin friction was 77kN/m 2 and the maximum skin friction was 129kN/m 2 .The allowable bearing capacity of the soil ranging from 64kN/m 2 to 71kN/m 2 for a shallow depth of 1m – 2m and 177kN/m 2 to 517 kN/m 2 for a deep depth of 10m to 20m. The pile sizes ranged from 305mm to 500mm. Design of the structural elements (superstructure) as well as the design of the foundations (Raft and Pile) were executed with ultimate column axial load of 4138 kN and serviceability column axial load of 2164 kN. The cost analysis was also performed. From the cost analysis, the cost of the raft foundation was N78,884,505.00 (Seventy Eight Million, eight Hundred and eighty four Thousand, five Hundred and five Naira only) while the cost of the pile foundation was N117,551,700.00 (One Hundred and seventeen Million, five Hundred and Fifty one Thousand, Seven Hundred Naira only). This showed that the cost of the pile foundation was greater than that of the raft foundation by 39%. It is recommended that raft foundation be used on the area in order to minimize cost.
Journal Article•
TL;DR: In this paper, a single expanding pier with three different lengths to diameter ratio was investigated by an axisymmetric numerical model, using a commercially available finite element code (Plaxis V.2010).
Abstract: Construction of the civil engineering structures on the soft soils, especially on the soft clays, is one of the most important challenges for Geotechnical engineers. In the most methods for improvement soft soils, increasing of soil stiffness and consequently increasing in bearing capacity can be considered as a suitable solution to prevent of unexpected settlements. Among the soil improvement methods, using expanding pier, at a low price and rapid method, has been developed in recent years. Cavity expansion theory can be considered to explain the mechanism of the formation of the cylindrical cavity due to radial consolidation in the soft clay’s soils. According to this theory, the surrounding soil of the formed cavity is compacted and consolidated after expansion and consequently a composite system including densified surrounding soil and a pier with more stiffness rather than soft soil can be created. In soft clays, after dissipation of the excess pore water pressure with time lapse, effective stress increases, and consequently settlement can be reduced. This paper investigates a single expanding pier with three different lengths to diameter ratio by an axisymmetric numerical model, using a commercially available finite element code (Plaxis V.2010). Two kinds of soils with different stiffness including the soft and medium stiffness were considered to investigate of influence of length to diameter ratio on the settlement with different expansion ratio. The soil that selected for this study is intended normally consolidated under self-weight (OCR=1). The results indicate that the ratio of final tolerated vertical load for expanded piers Vol. 18 [2013], Bund. S 4218 to piers without expansion, in which the final diameter are constantly in an equal settlement, do not follow up from the special pattern with changing in the length to diameter ratio. However, for equal stiffness and length, the mentioned ratio increases with increasing in the final expansion to initial diameter ratio.
01 Apr 2019
TL;DR: In this paper, the bearing capacity of isolated model footings which are hollow circular and solid circular in shape subjected to axial loading was investigated to analyze the effect of increasing inner diameter while keeping outer diameter constant (Do=15cm).
Abstract: This paper presents the experimental study of bearing capacity of isolated model footings which are hollow circular and solid circular in shape subjected to axial loading. The ring footing shape is characterized by outer diameter Do and the inner diameter Di, defined by ring diameter ratio, n= (Di/Do). In this study, behaviour of one solid circular footing (n=0) and four ring footings with n=0.166 (Di=2.5cm), n=0.333 (Di=5cm), n=0.666 (Di=10cm) and 0.866 (Di=13cm) were investigated to analyze the effect of increasing inner diameter while keeping outer diameter constant (Do=15cm). A relationship between load intensity, footing pressure, ring diameter ratio and settlement is developed for each type of footing to determine the influence of the above-mentioned parameters on the bearing capacity and settlement of the footing. These relationships depict that the bearing capacity varies with the change in ring diameter ratio. An efficiency factor is derived from the stress-settlement relation for different ring diameter ratio. It is found that for the hollow circular footings having n=0.166 and n=0.333, the failure pattern is comparable to the solid circular footing having identical bearing capacity and the load-settlement curve, this may be due to the more confining effect up to certain ring diameter ratio; suggesting the use of hollow circular footings over solid footings thereby making savings in volume of material used and the cost incurred.
Cites methods from "Foundation analysis and design"
...Bowles [10] had also predicted the bearing pressure and settlement of hollow circular footings using finite element method....
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20 Sep 2000
TL;DR: In this article, the problem of the realization of a double hit hammer for inserting piles in the ground as needed in construction has been addressed, and it is mainly shown that in parameter space of the mechanical system, there exists an operating window where the single cycle behavior corresponding to one stroke of the power system can be repeated in a stable periodic behavior with period equal to the one cycle one.
Abstract: The problem of the realization of a double hit hammer for inserting piles in the ground as needed in construction has been addressed. It is mainly shown that in parameter space of the mechanical system, there exists an operating window where the single cycle behavior corresponding to one stroke of the power system can be repeated in a stable periodic behavior with period equal to the single cycle one. As the applied control is a simple one, it would be of interest to consider technical experiments to check the usefulness of the concept.